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The Truth About Propylene Glycol, According to Sister Scientist, Erica Douglas

An ingredient found in many personal-care products like shampoo, hair conditioner, and styling products, propylene glycol is widely used because of its relatively low cost and versatile nature. Its inclusion in a formula can fulfill various purposes, making it a popular choice by cosmetic chemists. However, some manufacturers have recently decided to no longer include propylene glycol in their products.

Do not be alarmed by the term antifreeze or by the chemical, propylene glycol. It is safe at the low concentrations when used in personal care products.

This is possibly due to misinformation and propaganda circulated on the Internet in the interest of marketing “natural” products. I avidly support using natural products and avoiding putting toxins into our bodies whenever possible or practical. It can be frustrating to read inaccurate and incomplete information in an attempt to frighten consumers into using different products. In this article, Sister Scientist Erica Douglas, Cosmetic Chemist, and Beauty Industry Expert, discusses the science behind propylene glycol.

The chemical facts about propylene glycol

  • It is water-soluble.
  • It is synthetic.
  • It is non-toxic.
  • It is easily metabolized. 

Propylene glycol (also known as 1,2 propanediol) is a relatively small molecule with two alcohol (hydroxyl) groups (-OH). It is a colorless, odorless liquid that is completely water-soluble. PG is a synthetic product obtained from the hydration of propylene oxide derived from petroleum products. I do not consider a petroleum-sourced product a bad thing, as I consider the final structure and its properties to be more relevant than the source (unless contamination is a concern).

What is propylene glycol?

Propylene Glycol is a colorless, odorless, and tasteless synthetic organic compound liquid that belongs to the class of diols, which are compounds containing two hydroxyl (OH) groups. It’s chemical formula C3H8O2 or CH3CHOHCH2OH

The FDA has categorized propylene glycol as “Generally Recognized as Safe.”

Even with prolonged direct exposure, there is little to no skin irritation or sensitization. It subsides quickly once the area is flushed. The MSDS recommends avoiding direct handling due to potential irritation, which is a smart recommendation for any chemical–this does not indicate the toxicity level. Remember: in the chemical industry, when a worker is exposed to continuous and large quantities of a chemical in its concentrated form, it is imperative to use the strongest safety precautions possible. This is not relevant to consumers using a product by the teaspoonful if that.

Propylene glycol is non-toxic when ingested, even in reasonably large amounts.

Unlike its dangerous and frequently lethal cousin, ethylene glycol, PG is easily metabolized by the liver into normal products of the citric acid metabolic cycle, which are completely nontoxic to the body. Approximately 45 percent of any ingested PG is excreted directly from the body and never even comes into contact with the liver. The elimination half-life for propylene glycol is approximately four hours, and there is no bioaccumulation (buildup in the body over time). A few rare incidents have occurred where a person ingested a large quantity of propylene glycol and suffered some liver and neurological effects as a result, but these were short-lived and subsided once the material was metabolized and excreted.


The metabolic cycle for propylene glycol

  • Propylene glycol → lactic acid → pyruvic acid → CO2 + water

Both experimental and anecdotal evidence to date indicate PG to be completely non-carcinogenic, despite its “petroleum-based” origin. In an interesting study, some rats were fed propylene glycol at amounts equal to 5% of all their daily food intake for two years, which is a huge volume over a large portion of their lifetime. There were no observable effects on their health or behavior.

What are misconceptions or misinformation about propylene glycol?

Misconceptions or misinformation about the use of propylene glycol in cosmetic products has commonly made its rounds around the internet, predominantly due to lack of understanding, incomplete information and/or the amplification of isolated incidents. 

Contrary to some unfounded claims, we know that propylene glycol is generally safe to use at regulated concentrations. Also there is no concrete scientific evidence linking propylene glycol to cancer when used in cosmetics. 

While there are reports of rare sensitivities in individuals, propylene glycol is generally well-tolerated. True allergic reactions are infrequent, and most users experience no adverse effects.

Also, there are claims that it causes a drying effect.  However, technically Propylene Glycol is classified as a humectant, which means it has the ability to pull moisture in from the surrounding environment.

What “antifreeze” really means for consumers

The word is frequently used to alarm consumers, and is simply a scientific term used to describe the lowering or depression of the freezing point of a liquid. An example is the application of salt to roads and walkways in a snowstorm. This process helps melt snow and ice and prevent development of dangerous icy conditions. The salt accomplishes this by lowering the freezing point of water. This is an example of a “safe” chemical being used as antifreeze. Do not be alarmed by the term antifreeze or by the chemical propylene glycol. While few chemicals are entirely without risk, propylene glycol is considered to be safe at low concentrations and is used in personal care products and even food products.

Propylene glycol in personal care products

  • It is an effective humectant.
  • It is a solvent for fragrances and preservatives.
  • It can be used as an emulsifier or co-surfactant.
  • It is used as a solvent for pigments in cosmetics.
  • It can be used as a preservative due to its antifungal and antimicrobial properties.
  • It is frequently used in deodorants and antiperspirants.
  • It is found in hand cleansers and disinfecting gels.
  • It is a common additive in shaving creams and gels.

I think for those of us with curly hair, propylene glycol’s main benefit is the fact that it is a humectant, and a pretty effective one at that.

How propylene glycol affects hair

  • It applies like a humectant (attracts water to the hair).
  • It won’t cause build-up. 
  • It will not evaporate easily (which may cause dry hair).

How is it used in haircare products?

It is a common ingredient used across a variety of industries, including cosmetics, and has a multitude of usages. In cosmetics, one of its most common usages is as a humectant to help maintain skin/hair moisture.  It also acts as a solvent, aiding in the solubizing of other ingredients. Additionally, propylene glycol contributes to product texture, ensuring smooth application and absorption. Its versatility makes it a common ingredient in various cosmetic formulations, including lotions, creams, shampoos, and other personal care products.

The application of propylene glycol that is most relevant to those of us with curly hair is as a humectant. All the usual cautions apply with regard to its capabilities to attract water to the hair from the environment or to draw water from the hair to itself. Unless you have the perfect atmospheric conditions, you may experience problems with this ingredient.

Propylene glycol is a completely water-soluble material that will not build up on the hair. It is also important to note that it is a diol with low volatility, meaning it will not evaporate easily and cause dry hair in the manner of low molecular weight alcohols such as SD alcohol and isopropyl alcohol.

Does it cause any adverse side effects for the scalp or hair follicles?

There are is no significant scientific data linking Propylene Glycol to adverse reactions on the scalp or hair follicles.  It’s important to note that adverse reactions to propylene glycol are relatively uncommon, and the vast majority of individuals can use products containing this ingredient without any issues. Hair product formulations are carefully designed to ensure the safety and efficacy of ingredients, including propylene glycol. However, as with any skincare or haircare ingredient, patch testing is recommended, especially for individuals with known sensitivities or allergies. 

Are there everyday haircare products that typically use this ingredient?

Propylene glycol is commonly found in a variety haircare products from shampoos, conditioners, and styling products, to hair dyes and scalp treatments. Propylene glycol is approved for use at regulated concentrations in all types of cosmetic and personal goods products. 

As a curly, it would be wise to be aware if you are using products that contain this ingredient, just in case you observe increased frizz or dryness. Use plenty of moisturizing products to help lock moisture into your hair shaft, which can help prevent any problems caused by a humectant.

Editor’s Note: Since the original publication of this article discusses the use of propylene glycol in personal hair products and food, the popularity of e-cigarettes has brought increased attention to this ingredient. Propylene glycol is used as one of the three main ingredients in e-cigarettes, along with nicotine and flavoring. Propylene glycol has been designated by the FDA as “generally recognized as safe,” or GRAS, for consumption; however, according to the Federal Agency for Toxic Substances and Disease Registry, “We have little information about what happens to propylene glycol in the air.” The concern arises when propylene glycol is heated up and inhaled. In April 2018, the New York Times reported on the presence of formaldehyde in e-cigarettes, “E-cigs often use propylene glycol or glycerol to help transport nicotine and flavors and to create the big vapor cloud. We’ve known for a long time that when we heat these so-called carrier fluids, they can transform into formaldehyde.” Currently, there is little research on the long-term effects of inhalation of propylene glycol through e-cigarettes.


  • “Case Studies in Environmental Medicine (CSEM”>, Ethylene Glycol and Propylene Glycol Toxicity” 
  • What is Propylene Glycol?
  • Gaunt, IF, Carpanini, FMB, Grasso, P and Lansdown, ABG, “Long-term toxicity of propylene glycol in rats, Food and Cosmetics Toxicology,” April 1972, 10(2″>, pages 151-162.
  • Dow
  • McKay, T. “Humidity, Humectants and Hair”, online publication, Aug. 2007
The Benefits of Antioxidants for Your Hair, According to a Curl Chemist

Most of us have heard we should eat our vegetables, drink green juice, take vitamins, and slather on expensive skin creams loaded with these nebulous molecules. We’ve been told these antioxidants will help us appear young, beautiful, active and healthy. Right? But what are the benefits of antioxidants when it comes to your hair?

When you learn to care for your curly hair, you learn about the potential damage that can be caused by using certain ingredients, cleansing too often, chemical processes, and over-manipulating the hair.

Why does curly hair get damaged more easily?

Our hair is constantly bombarded by reactive species of molecules that slowly tear apart the complicated structure of each strand. Without adequate protection, damage grows continually worse until it becomes evident:

  1. Color fades quickly.
  2. The surface becomes rough and porous.
  3. Tangles, breakage, and frizz become the norm.

Curly hair is even more susceptible to this type of degradation. Fortunately, it has been found that some botanical oils, vitamin E, vitamin C, and beta carotene do indeed provide some protection against these environmental sources of free radicals. They also provide emollient properties and other benefits to the hair, and thus seem to be good additions to products for curly hair. They are not substitutes for wearing a hat and treating your hair kindly though, so protect those tresses!

With claims like these, it seems inevitable that hair care products showcasing these ingredients would make their debut on the shelves of hair salons, health food stores, and drug stores, and of course, in the natural hair market sector.

Do we really need antioxidants in our hair products?

Are antioxidants beneficial when used in topically applied hair care products, or are they another clever marketing strategy? A consumer armed with knowledge of what oxidative damage is, how it occurs, and what can be used to protect against it has the advantage when evaluating product claims and making purchases.

What is oxidative damage?

Oxidation is the process whereby a molecule loses an electron and is cleaved into its substituent atoms or groups. Some of these species are left having an unpaired electron in their outer shell, leaving them in a highly unstable and reactive state, as they are driven to complete their outer shells via pairing all electrons. These are called free radicals or reactive oxygen species (ROS).

What does oxidative damage do to hair?

Hair is not comprised of living cells, but its keratin-based structures are still susceptible to oxidative damage from a wide variety of sources. This damage leads to the following:

  • split ends
  • broken hairs
  • rough cuticles
  • frizz
  • tangling
  • lack of luster
  • diminished curl retention
  • loss of color, natural or artificial

Identification of free radical exposure can help a curly to reduce their overall risk of structural degradation.

In order to complete its outer shell of electrons, the free radical will attack adjacent molecules and abstract an electron from them, generating a new radical which is also unstable and seeks to “steal” an electron from its neighbors. This initiates a chain reaction, which is the basis of many polymerization reactions. It can also be destructive to living cells and systems.

Free radicals can attack cell lipid layers, DNA, proteins, and many other essential structures. This disrupts key biological processes and can result in aging, decreased function, and cancer.

How does ultraviolet (UV) exposure damage hair?

The sun’s rays penetrate the hair shaft and deplete of the natural melanin resident in the cortex, which will also alter the protein structures of both the cuticle and cortex.

The Benefits of Antioxidants for Your Hair, According to a Curl Chemist

Do chemical processes cause oxidative damage?

Chemical processing like bleaching and permanent dyeing are culprits in substantial oxidative damage. They attack both the lipids and the proteins in the cuticle structures. Exposure to ozone, pollutants, tobacco smoke, substances in our water–as well as radiation–all add to the continual exposure to free radicals and their damaging processes. Damage is pervasive and cumulative, and damaged hair becomes more porous and even more vulnerable to oxidative damage. For this reason, prevention and minimization are critical to preserve the health and beauty of hair.

Additionally, these processes contribute to formation of free radicals:

How do antioxidants prevent hair damage?

Antioxidants mitigate and prevent damage to cells and structures from free radical and reactive oxygen species by putting the brakes on the chain reaction that destroys everything around it. The mechanism by which they achieve this varies, depending upon the antioxidant, but generally it is accomplished via an electron or hydrogen donor process. These molecules are called free radical scavengers.

One common antioxidant is Vitamin E (α-Tocopherol), which donates an electron to an unstable free radical, rendering it stable, but becoming oxidized itself. However, rather than becoming a participant in the free radical chain reaction, the oxidized version of α-tocopherol is then either excreted or regenerated via reduction (hydrogen donation) by Vitamin C (ascorbic acid).

What are the benefits antioxidants for hair?

While it is well-established that antioxidants are highly efficacious both when taken internally and applied to the skin via cosmetic preparations, it is natural to speculate whether or not they have equal value when applied topically to the hair, which is not a living cellular structure.  Fortunately, the evidence indicates that there is plenty of benefit to be derived from the inclusion of antioxidants as components in formulations for rinse-off products, leave-in conditioners, and styling agents.

Check out: Curly products with antioxidants

Vitamin E, Vitamin C, and beta carotene have been found to have protective effects against environmental free radical assaults on hair.

In a manner similar to sunscreens, these materials form a sort of interactive molecular shield against the elements, at least temporarily. By preventing the destruction of melanin and synthetic dye molecules in residence in the cortex of the hair strand, free radical scavengers can be quite useful in improving color retention and maintaining the health and integrity of hair.  Experiments have also generated data that demonstrates the efficacy of topically applied antioxidants in mitigation of damage from both coloring and heat processes.

Oil soluble vitamins such as α-tocopherols and beta-carotene and vitamin A and lipophilic plant extracts are the more common antioxidants found in hair care preparations.  The reason for this is that due to exposure to air many reactive oxygen species are generated in the aqueous phase in the bottle of product, where water soluble vitamins such as ascorbic acid (Vitamin C) would be present.  The ascorbic acid is then rapidly depleted via oxidation reactions with the free radicals, and is thus comparatively short-lived in its availability to perform its preferred function on the hair.

One method chemists have used to circumvent this problem has been esterification of the ascorbic acid, which converts it to a lipophilic substance and increases its duration of efficacy.  However, this additive is more expensive and diminishes its potential to scavenge radicals in the aqueous phase when hair is wet, which is when it is needed.

Furthermore, it is the assertion of research chemists at Mibelle Biochemistry in Switzerland that the inclusion of both water soluble and oil soluble antioxidants provides the best range of protection. For this reason, they have been developing methods to include more stable water soluble antioxidants and blends (such as grape seed extracts + α-tocopherols) that provide highly effective protection of the cuticle and cortex, even in rinse-off products.  Another research team has taken the approach of encapsulating ascorbic acid in micelles comprised of a nonionic surfactant (Polysorbate 80) and mixed tocopherols.  This nanoemulsion is supplied as a gel-like aqueous solution that is easily mixed into a formula. The Vitamin C remains protected and active for a greater duration due to being in the interior of the micelle.

[1] F. Zülli, E. Belser, M. Neuenschwander & R. Muggli, Antioxidants from Grape Seeds Protect Hair Against Reactive Oxygen Species, Mibelle AG, Switzerland

[1] Behnam, Dariush (Rossdorf, DE), Aqueous solution of ascorbic acid and method for producing same, United States Patent 6774247, 2004, AquaNova German Solubilisate Technology (AGT) GmbH (Darmstadt, DE)

This article has been updated for clarity.

The Most Common Hair Product Allergies You Need to Know About

Recently I received a rather heated e-mail in which a reader objected strongly to one of my previous writings. I had concluded that a specific ingredient is generally safe for use in hair care products, but the reader’s personal experience had been one of severe allergic reaction. It was a dreadful experience for this person, and it brings to light the unfortunate and unavoidable fact that many of the ingredients used in hair and skin care are potential allergens or irritants. It is not at all uncommon for users to report reactions to seemingly innocuous ingredients that are generally recognized as safe and effective for most people.

What are allergies?

Allergies are a highly complex issue of the immune system, and reports seem to be on the rise, although it is difficult to determine whether that is due to increased incidence or increased awareness. One particularly confounding factor in these situations is that an immune system may mount an allergic response after years of repeated exposures to the material, which can be quite baffling and can sometimes lead to an ingredient being overlooked as the source of the problem.

MORE: 4 Common Allegens in Hair Products

jars full of ingredients

What is sensitization?

Sensitization is the word used to describe an allergic reaction that develops after repeat exposure to an allergen. Often, the first time a body is exposed to a substance it does not seem to know what to do with it and basically just observes it.  However, in subsequent exposures, it apparently recognizes the substance, and if it deems the material a dangerous intruder, it mounts an attack (immune response”> against it.

Occasionally, sensitization occurs after one small exposure, but more often it occurs after a single high dose or large surface area exposure, or after prolonged, repeat exposures over either small or large surface areas. This is why products such as hair dyes and relaxers recommend that you patch test a small area of skin every single time you plan to use the product.

Symptoms of sensitization to ingredients in hair care products can include development of a painful, pimply rash, scaly, itchy atopic dermatitis, contact dermatitis, eczema, inflammation and itchy, flaky scalp.  Systemic and/or anaphylactic reactions are unlikely given the typical quantity of any ingredient in a hair product and the relatively small area of exposure, but they are not entirely unheard of.

MORE: Hair Product Ingredients that Cause Acne

The Most Common Allergens


Preservatives are probably the most common ingredient category responsible for allergic reactions in hair care products.  Among these are the formaldehyde donor antimicrobials, which include diazolidinyl urea, imidazolidinyl urea, DMDM hydantoin, and quaternium-15, to name a few.  These ingredients are notorious with dermatologists for causing skin irritation. Another preservative family notorious for being sensitizers is the isothiazolinones.


Fragrances are also a notorious allergen for many people.  The manufacturers of these products do not usually disclose what is in their proprietary formulas, and they often contain many common allergens in addition to whatever compound(s”> are responsible for their characteristic scents.  For this reason, many consumers attempt to avoid fragrances, but most products contain at least a masking scent to cover up unpleasant odors from some of the other ingredients. This can present a genuine challenge to the sensitive person.

Ingredients derived from food allergens

People with extremely strong food allergies may also find themselves predisposed to having allergic reactions when exposed to ingredients derived from their food allergens.  This seems to be especially true for those with corn, nut, and wheat or gluten intolerances. Nut oils, wheat germ oil, wheat proteins, hydrolyzed wheat proteins and wheat amino acids should be avoided by those with the relevant allergies.  However, there are other ingredients derived from wheat and corn that are not labeled as such, and can truly be problematic for some people.  Vitamins E and A can be wheat-derived, while Vitamin C may be corn derived.  Propylene glycol and the ethylene glycol used to ethoxylate (PEG-modify”> materials can be corn-derived. While the science does not necessarily explain why these derivative products should elicit an allergic response, there are no few accounts of them doing so.  Therefore, it bears consideration.  One problem is that product labels are not required to denote the source of any given ingredient.

Botanical and animal-derived oils

Botanical and animal-derived oils such as coconut oil, argan oil, castor oil, avocado oil, canola oil, and lanolin have also all been found to produce allergic responses in a small percentage of people.  Others find their skin intolerant of mineral oil or petrolatum, which are petroleum-derived products.

The ingredient about which we were contacted was propylene glycol, which is generally recognized as safe, but is definitely also recognized as an occasional allergen. It is possible that allergy to this is more widespread than previously realized as well, or it may be becoming more common due to greater exposure to materials sharing the chemical features of the glycols. These include compounds modified by ethylene glycol to increase water solubility, such as sodium laureth sulfate, PEG-modified silicones, and other surfactants, and they are very prevalent in foods, medicines and cosmetics.

Typically allergies to these types of materials are accompanied by existing cofactors that seem to predispose a person to a reaction. These co-factors include pre-existing eczema, exposure to large areas of propylene glycol-based products such as cortisone, food allergies, as well as yeast and hormonal issues.  Also, some populations seem to be missing the necessary enzyme for the metabolism of these glycols.

MORE: Learn to Decipher Your Product Labels

Hair product ingredients

Potential Allergens in Cosmetic Products

  • Emollients: nut oils, argan oil, coconut oil, lanolin
  • Proteins: Wheat proteins, hydrolyzed proteins, amino acids
  • UV-absorbers: PABA, octocrylene, octylmethoxy cinnamate
  • Surfactants: sodium lauryl sulfate, sodium laureth sulfate
  • Humectants: propylene glycol, glycerol (glycerin”>, panthenol
  • Preservatives: isothiazolinones, phenoxyethanol
  • Formaldehyde donors: DMDM hydantoin, diazolidinyl urea, imidazolidinyl urea,
  • Fragrances: both synthetic and botanical
  • Vitamins: Vitamin E and A can be wheat derived.  Vitamin C is often derived from corn.
  • Glycols and triols: (glycerin and propylene glycol”>, polyols, ethoxylated polymers, ethoxylated surfactants

MORE: Surfactants, Sulfates and You

studying hair product ingredients

How do you know what to avoid?

Of the countless different ingredients used in hair and skin care formulas, most are generally safe and effective for the majority of the population.  However, many of these ingredients also carry the potential to be sensitizers for some people, producing reactions ranging from mildly unpleasant to truly severe. It is wise to know if you have any specific allergies and to carefully read labels and ask questions of manufacturers to determine whether or not  a product is safe for you.

One thing is safe to say, and that is that we are daily exposed to a far greater number of complex substances than our ancestors ever were: medicines both topically applied and ingested, foods treated with many chemicals, processed foods containing many additives, lawn care chemicals, pesticides, cosmetics with long ingredient lists, and chemically-treated clothing and furniture and carpet, just to name a few.  The potential for cumulative and synergistic effects is simply staggering when one considers it.

For these reasons, it is nearly impossible to predict when and if a specific ingredient or combination of ingredients in a hair care product may produce a deleterious response.

How to reduce the potential for an allergic reaction

One way to reduce the potential for a sensitization reaction is to reduce your exposure to all of these materials overall. Another thing you can do is to rotate your products, so that exposure is limited and your immune system can “rest.” Restricting the number of ingredients to which you are exposed by choosing products with shorter ingredient lists may be helpful as well. Unfortunately, in the case of allergies, natural is not always better, as many plant and animal-derived products are responsible for allergic reactions. There are companies who strive to create products that are truly hypoallergenic, such as Arbonne, but even still, there may be some who react to one of their ingredients.

MORE: Natural Hair Products That Cause Dry Scalp & Skin

This article has been updated for grammar and clarity. 

Alcohols and Your Hair, What You Should Know

We have all been told at one point in our curly journey that we should avoid the use of products containing alcohol, as it can be drying to the hair. As with most things in life, it’s not quite as simple as labeling *all* alcohols as “bad” or drying, which is why you may even have noticed this ingredient popping up in your conditioners. There are some alcohols that can cause dry, frizzy hair, but there are others that can work to condition the hair. There are some curlies who find that their hair struggles to retain moisture when using certain ingredients, and others who like the way their hair feels when using those same ingredients. We know having curly hair isn’t always straightforward, so we created this guide to help you master your ingredient labels and figure out which ingredients your hair likes – and which to avoid.

Some alcohols cause frizz, while others help prevent it. This apparent contradiction in performance is due to the structure of the alcohol. Alcohols are a class of materials defined by certain characteristics. They have a nonpolar carbon chain and a polar hydroxyl group (an oxygen atom bonded to a hydrogen atom”> bonded to one of the carbons in the chain (most often at the end of the chain”>. We’ll look at the various types of alcohols.

Short-chain alcohols

Figure 1: Schematic of an alcohol molecule

This group includes ethanol, SD alcohol, SD alcohol 40, Alcohol denat, Propanol, Propyl alcohol and Isopropyl alcohol.

Due to similarities with water molecules, the very small alcohols (ones with fewer than 3 carbons in the tail”> are slightly miscible (capable of mixing”> in water, while they can also dissolve oil and other ingredients that are not miscible with water. Thus, one function they can serve is to dissolve polymers or other additives prior to their addition to the aqueous portion of the formula.

These types of alcohols evaporate quickly due to their low molecular weight, and for this reason are often used as an additive to help decrease the time it takes for hair to dry. However, this can create dry, frizzy hair as it may cause the cuticle to be roughened and/or oil and water to be removed from the hair along with the alcohol (remember, these are often use as astringents for our skin for just this reason”>. Another function of these lower molecular-weight alcohols, particularly ethanol (SD alcohol, SD alcohol 40, Alcohol Denat”> is to ensure the proper, even spreading of styling products onto the hair.

Often used as an additive to help decrease the time it takes for hair to dry, this can actually create dry, frizzy hair, as it may cause the cuticle to be roughened.

Fatty alcohols

This group includes Lauryl alcohol, Cetyl alcohol, Myristyl alcohol, Stearyl alcohol, Cetearyl alcohol and Behenyl alcohol.

These larger alcohols are typically derived from natural sources, and have 12 or more carbons per molecule (typically 12, 14, 16, 18, and 20″>. This higher amount of carbon content makes these molecules oilier (also referred to as ‘fatty’”>. For this reason, they are often used as an emollient in skin and haircare products. They give a smooth, soft feeling to the hair shaft by helping the cuticle to lie flat on the surface of the hair. However, if used in excess, fatty alcohols can combine with the natural sebum found on the scalp and form a sticky substance that makes the hair look greasy.

Figure 2: Examples of different types of alcohols

Another function these fatty alcohols typically perform in shampoos and conditioners is as thickeners and as nonionic surfactants and emulsion stabilizers. In fact, a fatty alcohol content of 4-5% is very common for this purpose, especially in products where there is a need to keep the price lower than that of a formula containing an expensive polymer that could achieve similar results.

They give a smooth, soft feeling to the hair shaft… However, if used in excess, fatty alcohols can combine with the natural sebum found on the scalp and form a sticky substance that makes the hair look greasy.

Miscellaneous alcohols

Benzyl alcohol is a non-volatile alcohol used as a preservative in products. It should not impact the texture or feel of your hair. Propylene glycol is most often used as a humectant, because it has a hydroxyl group at each end of the molecule. This makes it much more hydrophilic (water-loving”>, so that it can attract and hold water to the hair.

What to watch out for

Some alcohols may cause our delicate curly hair to be dried and frizzy, and we do well to avoid those in most cases. However, other alcohols, such as cetyl alcohol, can help to condition our hair and make it soft and manageable. In general, curlies might want to be cautious of short-chain alcohols, and not so worried about fatty alcohols, benzyl alcohol or proplyene glycol. As with all ingredients, it is always best to use trial and error as a method to find what gives you the best results.

Take a glance at this article about what else you should look out for in your curly hair products, check out these alcohol-free products (if you’d rather go without”>, and share your thoughts with us in the comments below!

This article was originally published in October 2004 and has been updated with additional graphics.

The Science of Aloe Vera Gel

Aloe vera is a perennial succulent plant that has been treasured throughout the history of humankind for its many beneficial properties. Evidence of its use are found in ancient Egyptian and Greek histories. Once introduced to southern Europe in the early 17th century it quickly became an accepted medicinal plant. It can be grown easily in most climates, and is well-suited for patio and indoor habitats, making it a species found in many homes.

Several of the properties attributed to aloe vera gel include facilitation of wound healing (especially burns and abrasions”>, mitigation of damage from ultraviolet radiation, antimicrobial activity (antibacterial and antifungal”>, anti-inflammatory action, skin moisturization, digestion aid, as well as potential applications as an anti-cancer agent and a targeted, controlled release drug delivery agent. Investigation is being done to increase our understanding of the composition of aloe vera and of the mechanisms by which it achieves it extraordinary accomplishments.

Aloe Vera in Hair Products

Given its ready accessibility and apparently gentle and healing nature, it is unsurprising that aloe vera gel is also popular in cosmetics and hair care, particularly as a kitchen-chemist or home-herbalist ingredient. The claims made for what it can do for hair are fairly broad, and some should probably be viewed with a healthy degree of skepticism.

Aloe vera gel benefits to hair include improved detangling, moisture, scalp healing, remediation of dandruff, restoration of pH levels, decreased frizz, enhanced cellular regeneration, anti-inflammatory action for the scalp and generation of hair growth.

Many people report excellent results when aloe vera gel is applied on the hair after washing and conditioning, and before a styling gel is applied. Some curlies enjoy using aloe vera gel as a stand-alone styling agent, while for others, this does not supply sufficient hold or curl retention.

There have also been testimonies of aloe vera gel being drying to hair, that it contains protein which makes low-porosity hair stiff and dry, and many questions of whether or not it behaves as a humectant. Finally, inconsistent results have been obtained when using aloe vera gel from different sources. A quick peek at the complex chemistry of this wonderful plant should provide some insight into these observations and questions.

Emollient properties

Aloe vera gel smoothes the cuticle surface and also attracts and seals in moisture. Despite having a low amount of active ingredients on a molecular or weight basis (less than 1.0%”>, the specific combination and type of ingredients enable it to pack a significant punch.

It imparts detangling and conditioning by forming a polymer film on the surface of the hair, thereby smoothing the cuticle. This film also provides mild hold, but significant curl retention based on application of aloe alone is unlikely.

Humectant powers

The pectin and sugar molecules can deliver moisture to the hair, and the amino acids and trace amounts of protein present can strengthen the cortex of damaged hair. It can act as a humectant as well, which can be beneficial in certain climates for specific hair types, but can also be a detriment in others.

Finally, aloe vera gel contains minerals such as iron, calcium, potassium, magnesium, and other micronutrients that may be beneficial to the hair and scalp. Aloe vera makes an excellent leave-in conditioner to be used underneath styling products to provide extra protection for delicate tresses. It is completely water soluble, so can be used regardless of the preferred cleansing regimen.


The aloe vera plant stores water in its leaves, which allows it to thrive during arid periods in climates where rainfall is sporadic. “Gel” is the terminology used to describe the mucilaginous material obtained from the parenchyma tissue of the plant. This slimy substance is approximately 99.0 – 99.5% water. The remaining 0.5-1.0% is comprised of a highly complex mixture of many components consistently mainly of a number of polymeric carbohydrate molecules called polysaccharides that contain building blocks of different small molecule sugars (monosaccharides”>. While a number of polysaccharides are present, the primary ones are acetylated mannan and pectin substance.

These polymers provide the structure to this aqueous system which gives it its mucilage. Mannans are also responsible for binding cellulose and for acting as signaling molecules for plant growth. Pectin substance includes several closely-related polysaccharides such as pectin, pectic acid, and arabinogalactan.

Polysaccharides have many hydroxyl groups pendant to the chain, available for hydrogen bonding, and for this reason are very hydrophilic and water soluble. This hydrophilicity also means that polysaccharides attract water from the atmosphere and bind it to the polymer surface, which is classic humectant behavior. This can have important ramifications for curly hair, especially.

It provides protein lectin and amino acids

These can be absorbed into the cortex of hair, to greater extents by hair with greater porosity, where they can add structural integrity to the hair.  However, some hair types become overly stiff and brittle or dry when protein accumulates on or in it, so it is wise to be aware of the presence of these materials in anything applied to the hair.

The balance of the components in aloe vera gel include several vitamins, organic fatty acids and triglycerides, minerals, enzymes, amino acids, proteins, simple sugars, and other compounds.

Key ingredients

  • Polysaccharides (carbohydrates”>: mannan, acetylated mannan (also: acemannan”>, pectic substance, cellulose, galactan, arabinogalactan, xylan.
  • Fatty acids: γ-linolenic acid, arachidonic acid, salicylic acid, uric acid.
  • Vitamins: α-tocopherol (vitamin A”>, B vitamins including folic acid, ascorbic acid (vitamin C”>, β-carotene, choline.
  • Protein: lectin, lectin-like substance.
  • Inorganic elements and minerals: chromium, calcium, magnesium, manganese, sodium, copper, iron, phosphorous, potassium, zinc.
  • Various organic molecules: monosaccharides (sugars”>, enzymes, amino acids, anthroquinones, chromones, miscellaneous.


Investigators have observed that there is significant variation in the polysaccharide content and composition of aloe vera gel.  This has been found to be dependent upon many factors. Extraction and processing methods have a huge impact on the polysaccharide content of the gel. Polysaccharides are highly susceptible to degradation from temperature and shear forces. Season of growth and location create variations also. There have even been differences observed from leaf to leaf of the same plant. This is a potential explanation for variability in performance noted by different users. As with many things in nature, some degree of flexibility may have to be acceptable.

Most “100% pure Aloe vera gel” available for purchase is a mixture containing some aloe, polymers for viscosity modification, preservatives and other additives. These additions will necessarily change the impact of the aloe vera on your hair as well.

For example, one of the most popular aloe vera gels among the curly community is Fruit of the Earth Aloe Vera Gel. Its ingredients are: aloe vera (aloe barbadensis”> gel, triethanolamine, tocopheryl acetate (vitamin E”>, carbomer 940, tetrasodium EDTA, DMDM hydantoin, diazolidinyl Urea.

This article has been updated.
What is Quaternium-80 in Curly Hair Products?
What is Quaternium-80 in Curly Hair Products

What is Quaternium-80?

Quaternium-80 is a conditioning ingredient found in moisturizing shampoos and conditioners. It is reported to be a great emollient and detangler, but its name causes quite a bit of confusion as to its role and mechanism by which it performs in products.

Is it a polyquat?

Curlies often want to know, is Quaternium-80 a polyquat or silicone, and is it prone to buildup? Is it water soluble? These are important questions to curlies who want to maintain their high standards of care for their hair. Fortunately, a quick look at the chemical structure of this ingredient and a comparison to other common categories of conditioning agents will provide us with lots of good insight about it. 

What does quaternium mean?

The International Nomenclature for Cosmetic Ingredients (INCI”> system of naming is not always descriptive and specific like the International Union of Pure and Applied Chemistry (IUPAC”> system, so sometimes the names are a bit mystifying. The term quaternium is a hybrid word used as chemical shorthand to describe quaternized ammonium cation compounds.

Quats are molecules or parts of molecules that contain a central nitrogen atom bonded to four different species, which imparts a positive charge to the central nitrogen atom. In cosmetic applications, quaternium refers to certain cationic surfactants that have a fatty acid-derived hydrophobic tail with a hydrophilic quaternized ammonium head.

A few examples of common quaternium compounds used in hair care products are stearalkonium chloride, cetrimonium chloride, cetrimonium bromide, and behentrimonium methosulfate. These molecules are water soluble, very versatile, and are used in oil-in-water systems as conditioning agents as well as emulsifiers for water insoluble ingredients such as silicones.

What do quaternium compounds do?

The cuticle surface of hair possesses a mild overall negative charge, which becomes more pronounced in color-treated, chemically-processed, or otherwise damaged hair. Positively-charged head groups of quaternized ammonium surfactants adsorb onto the surface of the hair as a result of electrostatic attraction to these negatively-charged sites. The molecules are held in place at that site, and the hydrophobic tail of the surfactant molecule drapes itself along the axis of the hair strand, forming a film on the surface of the cuticle. This film provides several benefits, including facilitation of wet and dry combing and detangling, elimination of static electricity and fly-away hair, and improved slip and tactile feel, i.e. silky hair.

What are polyquats?

Polyquaternium materials are polymers that have been modified to have multiple cationically-charged quaternized ammonium sites along their backbones or hanging pendant from the backbone. These substances adhere extremely well to hair and form a smoothing, protective film, because the many positive sites bond with many negative sites on the cuticle surface. This makes them fabulous conditioners for many people, and they do provide many benefits such as improved color retention and some thermal protection as well. However, some people experience buildup or unwanted accumulation of these materials on the surface of their hair, due to the tenacious nature of the bond formed between the polymer and the cuticle.

Quaternium-80 is a “Silquat”

Quaternium-80 is a member of a group of specialized quats (sometimes referred to as silquats or silicone quats“> that have a quaternized ammonium head and a silicone tail, rather than a hydrocarbon one. Although quaternium-80 is not a polyquat, it is actually a polymer with a silicone middle, and a positively-charged ammonium ion on each end. The silicone portion does not have multiple cationic sites along its backbone, so it does not pose the same problems as polyquats with regards to removal. Its water soluble nature means that a mild shampoo or conditioner wash should be completely sufficient to remove it from the surface of the hair.

Quaternium-80 is:

  • a cationic surfactant known as a quat
  • a modified silicone
  • water soluble

Quaternium-80 is not:

  • a polyquaternium (polyquat”>

This specialized polymeric surfactant has been found to provide excellent targeted conditioning and anti-static properties in a manner similar to other quats, but with superior detangling and wet combability. Where it really stands out is in the high amount of gloss and shine it provides, as well as the very silky tactile feel reported by users in laboratory trials. The silicone portion of the ingredient is undoubtedly responsible for its unique performance. Since it is water soluble, the enhancing properties of a silicone polymer can be enjoyed without fear of build up.

What is Quaternium-80 in Curly Hair Products

Products with Quaternium-80


In closing, the silicone quat ingredient quaternium-80 is a conditioning agent that provides excellent benefits, especially to regions of greater damage on the cuticle. It is very substantive and forms a smooth, protective film over the hair, and provides anti-static effects, ease of combing and detangling, a silky feel, and high gloss. While it does adsorb onto the surface of and adhere to the hair to provide durable conditioning benefits, its water soluble nature and few (only two”> quaternized sites mean that it is relatively easy to remove from the surface of the hair, unlike polyquaternium conditioners. 

What a Curl Chemist Wants You to Know About the Sun

Photo courtesy of Africa Miranda

As summer approaches, we are drawn to the outdoors, whether for a day at the beach, a few hours on the golf course, an afternoon at the swimming pool, or a tropical vacation for a week in the sun. We all know the dangers of sunlight to our skin, and most of us take plenty of precautions to protect ourselves from those harmful UV rays when engaged in these types of outdoor activities, but what do we do to protect our hair? You may wonder why our hair needs any sun protection at all. After all, it is dead already, is it not? You might also have heard that sunscreen is important for the hair, but may be confused about why it is important or what to look for in a product. Here’s some insight into the importance of protecting our hair from the damaging rays of the sun.

Why does it matter?

Most of us are familiar with the lightening of our hair that occurs when we spend hours in the sun in the summer. To many people this is even a desirable side effect of sunbathing. However, this effect is evidence of the destruction of pigment in the hair as a direct result of UV-induced oxidation of melanin particles in the cortex. This effect is particularly devastating for those of us who rely upon the wonders of hair dye to enhance our natural coloring, because the molecules used in hair dyes to add color to hair are even more susceptible to degradation via ultraviolet radiation. UV radiation also can cause cleavage of molecular bonds in the hair, ultimately leading to fracture of the cuticle and the cortex. This can lead to dry, brittle hair, rough texture from damaged cuticles, split ends, and breakage.

What can we do?

The solution is fairly simple. We can wear a hat or scarf every day, which really may not be an acceptable solution for everyone, or we can use products that contain sunscreen in order to give our hair the same protection we give our skin. These products are highly effective in the prevention of color fading, especially if the products are used daily, and protect hair from incidental sun damage that accumulates when going about our normal routines. In fact, it was the development of products with the goal of color preservation that led to the recent boom of formulas that contain UV absorbers in them. There are many new products available that contain sunscreens, including shampoos, rinse-off conditioners, leave-in conditioners and styling products.

UVA? UVB? – What in the world?

Ultraviolet radiation is a small a portion of the entire spectrum of electromagnetic radiation. We are surrounded by all types of electromagnetic radiation in our daily lives. Other parts of the spectrum are the gamma ray and x-ray regions, visible light range, infrared, microwave, and radio waves. Each region occupies a specific range of wavelengths or energy in the spectrum. Ultraviolet radiation (UV”> occupies the wavelength range (320-400 nanometers”> directly adjacent to visible light (400-700 nanometers”>, with smaller wavelength and higher energy than visible light. The higher the energy of a wave, the greater potential it has to interact with and react with our fragile human bodies. This is why so much caution is exercised when we encounter x-rays in medical testing. Fortunately UV rays are more easily combated than x-rays, which is why we don’t have to wear lead suits when we go to the beach.

The UV range is typically broken into two regions: UVA and UVB. UVB comprises a narrow band with wavelengths from 280-320 nanometers and is typically associated with causing sunburns. UVA is a broader range, from 320-400 nanometers. These lower energy waves are thought to be the source of much of the aging caused by the sun.

What ingredients do the trick?

There are several types of ingredients that can help prevent sun damage to the hair and skin. The two recognized classes for sun protection ingredients are UV-absorbers and UV-blockers. UV blockers work by physically blocking the UV rays from the skin or hair. They are effective across the entire UV spectrum and are non-toxic and non-irritating to the skin. However, the trait that gives them their ability to function in the sunscreen capacity also tends to make them appear rather opaque and white in application. This renders them highly undesirable in hair care applications, as they would make the hair appear dull and lifeless. Work has been done and is being done to overcome this obstacle, but for now UV-absorbers are the ingredient of choice for most hair care products.

UV-absorbers are typically organic compounds that contain conjugated double bonds (usually aromatic rings”> and oxygen-containing carbonyl groups. Most of these molecules function by absorbing the energy from UV radiation ,which puts them into an elevated energetic state. They then undergo what is known as a vibrational relaxation transition which returns them to their normal, ground state. They can then absorb more photo-energy. This allows the sunscreen molecule to remain effective for a long period of time. Some other UV-absorbers actually undergo a reaction which eventually renders them ineffective as sunscreens. However, they provide very high levels of initial protection from the sun’s harmful rays, and are thus useful for short outings. An example of this is avobenzone.

Most UV-absorbers function really well in either the UVA or UVB region, but not in both. For this reason many are used in combination with one another in formulations designed to provide the best coverage against damage from the sun.

There have also been some new developments of polymeric UV-absorbers designed especially for hair care products (Solamer, by Nalco”>. The exact nature of these polymers is still proprietary, but one can assume they contain multiple sites for UV-absorption through the mechanism described earlier in this article. The multiple sites for UV-absorption make these polymers highly effective in hair care products. The manufacturer also claims excellent water solubility of the polymer while maintaining that it will be substantive to the hair when applied.

In conclusion, we have learned the importance of protecting our hair from the damaging rays of the sun. Many newer products have UV-absorbing ingredients in them, so choices are becoming more widely available. Check near the bottom of the ingredients list for some of the molecules listed above, try some product on your hair, and go out and enjoy the summer! Keep in mind that many of the sunscreen additives are water-soluble, so it is advisable to reapply protection to your hair periodically if participating in water sports.

UVA absorbers

  • Oxybenzone
  • Avobenzone
  • Dibenzoyl methanes
  • Benzophenones
  • UVB absorbers
  • P-aminobenzoic acid (PABA”> and derivatives
  • Camphor derivatives
  • Cinnamates (octyl methoxy cinnamate, ethylhexyl cinnamate”>
  • Salicylates
  • Phenylbenzimidazole sulfonic acid
Read more: Smoke Points: Why Oil Doesn’t Work as a Heat Protectant

This article was originally published in 2015 and was updated in 2018.

Does Vitamin C Really Make Your Hair Grow?

Vitamin C has long been touted for its beauty benefits from anti-aging properties for younger-looking skin to growing longer, stronger hair and nails.

Are these just marketing claims that the cosmetics industry is using to make you think the products are natural, green, and healthy? Or are there true benefits to applying vitamin C externally to your hair and skin? Perhaps not surprisingly, the answer is sometimes yes, sometimes no.

What are the benefits of vitamin C?

Benefits for skin

Vitamin C is a popular component of many topically applied skin care products, where it has definite observed benefits when used above certain concentrations (5-15%”>.


At the surface, it acts as an anti-oxidant, combating damage caused by free radicals created by environmental pollutants and ultraviolet radiation exposure. This can help prevent formation of new wrinkles that occur when free radicals are present on skin.

Increased collagen

Vitamin C has also been shown to penetrate and transfer to epidermal tissue, where it aids in cellular repair, and promotes collagen production. It is beyond the scope of this article to explore all of the mechanisms and variables by which vitamin C benefits skin, but clearly, it does provide some genuine value.

Whether or not it provides benefits to hair is less dependent upon complicated cellular processes, and more dependent upon some basic chemical properties.

Chemical structure

Vitamin C is the common name for ascorbic acid, a small chiral molecule — in other words, one that can occur in two different forms that are non-superimposable mirror images of one another. The type of ascorbic acid found in plants, synthesized in animals and used in cosmetic and food products is the left-handed molecule (levorotatory enantiomer”> of ascorbic acid (L-ascorbic acid”>. For whatever reason, the right-handed version (dextrorotatory”> does not occur in nature and the lab-synthesized version offers no benefits over its more readily available isomer.

Benefits for hair

Mild cleanser

As with many acids, vitamin C — ascorbic acid — can act as a mild clarifying agent in shampoo and can be effective in helping remove mineral buildup accumulated on the surface of the hair. This improves the ability of the hair to accept moisture, which makes it more soft and supple and more resistant to tangling and breakage.

Shine enhancer

Also, the lower pH of acidic shampoos smoothes and tightens the cuticle surface, rendering the hair more-evenly reflective and shinier.


The presence of multiple hydroxyl groups (oxygen-hydrogen, -OH”> makes ascorbic acid extremely hygroscopic, meaning it attracts and binds water to itself. For this reason, vitamin C can act as a humectant and effective moisturizer in hair products when used in conditioners, leave-in conditioners and styling products.


Also, when included as a component in leave-in conditioners and styling products, vitamin C can act as an antioxidant, much in the same manner as in skin creams. Free radicals can cause structural damage to the proteins in hair, which can lead to split ends and breakage.

Color retention

They also can react with both natural melanin and synthetic dye molecules resident in the cortex of the hair strands and bleach color from hair, while simultaneously causing physical damage to it. For this reason, free radical scavengers such as vitamin C can be quite useful in color retention and maintaining the health and integrity of hair. Ascorbic acid is water soluble, and is thus not a concern for buildup or accumulation on the surface of hair, even when non-mainstream cleansing methods are employed (low-poo, no-poo”>.

Oftentimes, vitamin C is used as a preservative or pH adjuster in hair care products and has no significant impact at all on final properties of the product. If it appears as one of the last few ingredients, below what is known as the one-percent line, you can be assured that this is the case.

Does vitamin C make your hair grow?

The marketing materials for some hair care products claim that their vitamin-C containing formula can promote hair growth and repair an unhealthy scalp. While it is certainly true that ascorbic acid is capable of transfer to tissue and cells in specifically formulated skin care products where it can participate in cellular processes, this isn’t usually the case in shampoos and conditioners.

The reasons for this are that the pH of hair care products is generally too high for the acid to be active, and the concentration of the ascorbic acid is too low for there to be any benefit. For this reason, most of these types of products will have no significant impact to the scalp or hair growth.

However, it is possible that a formula intended for direct skin application might be of some benefit to the scalp tissue. Whether this would promote hair growth is not certain, but a healthy scalp is in the best position to perform this function. This would probably fall into the category of “it couldn’t hurt to try in moderation.”

Possible side effects

Some users have reported that some vitamin C-based products have felt drying to their hands and hair. This is going to be very dependent upon an individual’s hair and skin type. as well as on the other ingredients in the formulation. It is doubtful that the vitamin C itself leads to dryness, but perhaps if coupled with harsh surfactants, a too-low pH, or insufficient emollients and moisturizers, a product could produce that undesirable tactile feel.

Always trust your own reaction to a product and use what works for you!

Have you used vitamin C for hair growth? If so, what was your experience? Share it with us in the comments below!

This article was originally published in 2016 and has been edited.

The Pros & Cons of Shampoo Bars

Pictured: [Obia Shampoo Bar](”>

Shampoo bars made of “all natural” ingredients are all the rage in the hair- and skin-care markets. These handmade soaps and shampoo bars are especially gaining popularity in the curly-hair community because they tend to be free of sulfates and silicones and are made from moisturizing oils and gentle cleansers.

Many people report that they are extremely pleased with the results they are getting, citing benefits such as increased softness, better curl formation and, in some cases, elimination of the need to use conditioner.

However, not all users have had such pleasant experiences, and there is some confusion over what the advantage is of shampoo bars over traditional shampoos or low-sulfate or sulfate-free cleansers. There is also some debate about whether the shampoo bars should be followed up with a vinegar rinse, a conditioner, or both.

As usually do, I will delve into the basic chemistry of shampoo bars to discover what answers lie beneath the surface.

What is a Shampoo Bar?

Soap molecules used in shampoo bars are similar to some of the more familiar hair cleansers such as sodium lauryl sulfate in that they are anionic (negatively charged”> surfactants. The difference is that the polar head group of the molecule is a carboxylate, rather than a sulfate (R-COO-Na+ vs. R-OSO3-Na+”>, which results in a milder surfactant. They are formed by reacting a fat (triglyceride”> with a strong base, either sodium hydroxide (lye”> or potassium hydroxide (potash”>, in a process called saponification. In this reaction, the fatty acids are cleaved from the triglyceride backbone and in a two-step chemical reaction soap molecules are formed, along with water and glycerin. The amount of strong base needed is calculated based upon published saponification values for the fats being used in the process. Although the source of fats is natural, there is still a chemical reaction and modification that must be done to get a useful derivative.

Typically, an excess of oils is added to the mixture prior to the mixing of fats and base. This provides two benefits:

1. The lye is completely consumed in the chemical reaction, which makes certain the final product doesn’t burn or irritate skin or damage hair.

2. The excess oils act as “superfatting” agents in the shampoo bar, which contribute to mildness and an overall luxurious feel to the soap. These oils act as moisturizing and conditioning agents, much as they would in a regular shampoo or conditioner.

naturallycurly.comSchematic of the chemical reaction for soap making (saponification”>.

Most handmade soap makers use a “cold process,” where the main source of heat used is from the exothermic reaction itself (unless the oils or fats need to be pre-melted”>. The lye or potash is added slowly to water, which quickly becomes hot. It is set aside for a few minutes to cool slightly while the oils are mixed separately. The basic solution is then mixed with oils and stirred until it begins to thicken. Essential oils and colorants can be added at this time, and then the soap is poured into molds. After it cools for a few hours, it can be removed carefully from the molds and cut into bars if needed. These individual shampoo bars are then covered and left to “cure” on racks for a few weeks. This ensures that all of the lye is gone and that the soap is hard.

You may note that in this process, glycerin, a byproduct of the saponification reaction, is left to add humectant and lubricative properties to the soap. It is important to be aware of this because it can potentially be problematic for those with colored hair, especially if the hair was colored recently, if temporary dye was used or the if hair color was heavy in red dye. The humectant properties of glycerin can be a boon or curse for curly hair also, depending upon the hair type, condition of the hair, and environment in which the product user lives.

Soaps are classified as gentle cleaners due to being less efficient at removing oil from the hair when compared to some of the synthetic surfactants. This is a beneficial property in a cleanser for those of us with hair already prone to being dry. The excess oils in a superfatted soap act as emollients and moisturizers to replace oils removed from the hair during the cleansing process. Curly hair doesn’t typically have much oil from the scalp distributed down the hair shaft in the first place, so it needs this extra moisture added in a cleansing routine.

The properties of any particular soap may vary greatly, depending upon which oil or combination of oils is used to make it. Coconut oil is admired for its luxurious, foamy texture. Olive oil (castile soap”> is considered to be unparalleled for skin with any types of eczema or psoriasis problems and is very gentle with hair. Evening primrose oil and calendula oil, while expensive, can also add healing and moisturizing properties to the soap. Jojoba oil is very similar in composition to human sebum, so it is great at dissolving old sebum, cleansing the scalp gently and replacing some of the natural oils. Shea butter is prized for being an excellent moisturizer, and soaps with this ingredient included can leave the hair and skin feeling soft.

The Drawbacks of Shampoo Bars

When used in soft water, soap can generate a nice lather and leave hair feeling very soft and clean. In fact, in really soft water and after using an extremely moisturizing soap, the soft and slippery texture of our skin and hair can feel so foreign to us that we may continue rinsing repeatedly in an attempt to remove the perceived residue.

Unfortunately, soap’s effectiveness is significantly reduced when used in hard or acidic water. The reason for this is that the carboxylate group on the soap molecule interacts preferentially with the metallic ions that are so prevalent in hard water (usually calcium, iron, and/or magnesium”>. The result is the formation of a precipitate, which leaves an insoluble film on whatever surface comes into contact with it, including the hair. This film can be very difficult to remove and leaves the hair dull, lifeless, tangled, and dry. The soap lathers less and cleanses less effectively for the same reason: two soap molecules are removed from action by each magnesium or calcium ion when the complex is precipitated from the solution, so there is less soap available for cleansing. That squeaky clean feeling you may get after using a bar soap is actually the feel of organic/mineral deposits on your hair shaft. This deposit left on the hair can also attract dirt, making hair greasy and dirty. This problem was one of several driving forces for the development of synthetic surfactants such as sodium laurel sulfate.

Another potential hazard of the shampoo bars and soaps is that they typically have a pH in the 8 to 9 range, which is substantially more basic than the natural level for hair. This can result in a temporary breakage of disulfide bonds in the keratin protein of the hair, which can disrupt curl formation and cuticle structure. The basic environment softens the hair, swells it, and leaves it with a ruffled cuticle. This rough surface is not only a source of potentially damaging entanglements and breakage, but also is unattractive because it reduces the shine and gloss of hair tremendously. Swelling of the hair also enables larger colorant molecules to escape, which can shorten the lifetime of a coloring application.

Fortunately, there are a few things you can do to counteract these two effects. Some soap makers put various additives in their soaps that help to keep the soap molecules from binding with hard water metals (sodium silicate, sodium carbonate, borax”>. However, in the “all-natural” products this is not likely, so it is important to take some steps after shampooing. Rinsing with a mildly acidic solution will help dissolve the soap scum deposit from your hair, shrink the hair shaft diameter, flatten the cuticle and increase the shine and smoothness of your hair. White vinegar, apple cider vinegar, or dissolved citric acid or vitamin C (ascorbic acid”> all have sufficiently low pH to help return hair to its preferred pH pf approximately 4-5. Using a clarifying shampoo with EDTA in it can also help remove build up, but would also involve use of a more harsh surfactant, so might be best done only occasionally.

You can also try washing your hair in bottled, purified water when you use your soap, which would make this step necessary less often. Another option is getting a showerhead filter, which is generally less expensive than a whole-house water softener. Even if you take these steps, it is wise to do a mild acidic rinse, due to the basic properties of the soap. Also, dirt on your hair can have minerals in it, which can then create soap scum, so you can’t avoid the need for the low pH rinse entirely.

Depending upon the composition of the soap you are using, the condition of your hair, and the type of water you have, you may find you need to use less conditioner than when you use other cleansers. Experimentation will help you figure out what helps your hair look and feel its best.

How can I incorporate shampoo bars into my hair care routine?

  • Look for one with the plant-derived oils which you prefer, or buy a few bars and try different recipes.
  • Lather the bar in your hand, not on your head. Your hair is as fragile as a cashmere sweater, and needs very careful handling at all times.
  • Use soft water to wash your hair with soap bars whenever possible.
  • Follow up with a mildly acidic rinse to restore the natural pH of your hair and to impart that shiny, glossy surface we all desire.
  • Use detangler or conditioner to your own personal tastes. In other words, if you still feel you need it, go ahead! I personally wouldn’t skip that step unless my hair looked weighed down or limp.
  • Give it a few tries. I have read that it can take some time for your scalp and hair to adjust, just as it often does when you go to a low shampoo or shampoo free routine.
  • Report your results to us!

I plan to head to my local health food store soon for some shampoo bars, or maybe don my chemist gear and make some myself!

Additional reading about pH and hair is available here.

What Humidity, Humectants and Dew Points Mean for Curly Hair

curly candace


As we head into springtime, many curlies apprehensively anticipate the return of humidity — and frizz.

Weather is a constant variable that can toss a kink into the best of hair days. Who among us hasn’t left the house with perfectly coiffed curls, only to step out into a hot, sticky afternoon or a damp, foggy morning and see our hair lose all recognizable shape, inflate to twice its normal size and develop the texture of a piece of steel wool?

Wouldn’t it be spectacular if there was some crystal ball that could tell us each morning what the weather patterns would be and what exact products to use that would enable us to circumvent this seemingly unavoidable hair disaster? Although that might not be realistic, there are some clues available to us in the morning weather report or on NaturallyCurly’s Frizz Forecast. Learning some basic facts about humidity, humectants and the dew point can arm you with the knowledge you need to select the right types of products to keep your curls looking their best, whether the weather is bone dry or warm and muggy.

What is humidity?

I am neither a meteorologist nor an expert in the thermodynamics of gaseous mixtures, but I am going to tackle this topic even though it makes my brain hurt. Water coexists in the atmosphere with the gaseous mixture (primarily oxygen and nitrogen”> that makes up our air. We all are aware of the fluctuating levels of moisture in our air — especially those of us living here in the great southern swamplands of the United States.

A description of the moisture content in the air can be expressed using different terms and based upon various calculations. The two most familiar to us are relative humidity and dew point, which are both typically disclosed in our local daily weather report. Even armed with all this information, it can be confusing for one to understand just exactly how humid it is.

Relative humidity is key

Relative humidity expresses the relationship between the vapor pressure or vapor density (g/m3″> of the water in the air at a specific temperature versus the saturated vapor pressure of water at that temperature.

RH = (actual H2O vapor pressure/saturated H2O vapor pressure”> x 100

The saturated vapor pressure for water changes substantially with temperature. So as the temperature increases or decreases, the value for relative humidity changes, even if the overall water content in the air remains unchanged.

Example: We have an actual vapor density of 6.6 g/m3, and a temperature of 86°F. The saturated vapor density for water at this temperature is approximately 30.4 g/m3. This gives a relative humidity of approximately 21.7 percent. If the temperature increases to 98.6, the saturated vapor density increases to 44 g/m3, and the relative humidity becomes 15 percent. Conversely, if the temperature were to decrease substantially to 55°F, the saturated water density decreases to 11.35, and the RH increases to a value of 50 percent! If the temperature is gradually decreased to approximately 37°F, the relative humidity approaches 100 percent.

(See this site for a great chart and all sorts of additional information”>.

What is the Dew Point?

Oxygen and nitrogen are always gases at the temperatures found in our atmosphere, and the molecules bounce around in the air exhibiting ideal gas behavior (conforming to certain thermodynamic laws”>. Water, with its relatively high boiling point, exists in all of its phases at our atmospheric temperatures. Primarily, in our atmosphere, it is constantly exchanging between its liquid state and its gaseous state. One way of thinking about dew point is that it is the temperature at which the number of gaseous water molecules being formed is equal to the number of liquid water molecules being formed (Evaporation rate = condensation rate”>. When the temperature reaches the dew point, the relative humidity is 100 percent. If the temperature decreases below the dew point, water must condense out of the air, and fog, dew, or clouds are formed.

We can see by a quick review of our previous example that had we chosen a greater value for our actual water density (meaning a higher level of water in the air”>, our relative humidity values would all have been higher, and our dew point would also be shifted to a higher value.

So we can conclude that a higher value for our dew point necessarily means a higher concentration of water vapor in the atmosphere, and a lower dew point means less moisture is in the air.

A common question among curlies is at which dew points are humectants helpful and desirable, and at which dew points are they perhaps harmful and undesirable? Before answering that question, let’s review humectants and touch on “anti-humectants” as well.

What are Humectants?

We have spent significant time in the past discussing the chemical and physical nature of humectants and their relevance to the health and beauty of curly hair. To summarize quickly, humectants are molecules that possess atoms and groups of atoms that attract and bind water to themselves. They can have benefits and drawbacks for curly hair, and their performance is often very dependent upon the amount of moisture in the environment. This variable performance is due to the driving force in nature to reach and maintain a state of equilibrium.

Dry hair, placed in a wet, humid environment, quickly absorbs water from the air. Unprotected hair can quickly lose all of its internal moisture and become very dry in an arid environment. Humectants applied to the hair draw water to themselves from whichever source is greater — the atmosphere or the hair.

For more in-depth information on this topic, read this article.

What is an Anti-humectant?

An ingredient may be called an anti-humectant if it fulfills several requirements. First, it must not be hygroscopic, meaning it must not possess molecular traits that cause it to attract water molecules to itself. Second, it must be water repellent, which necessarily means insoluble in water. This property allows it to lock out or prevent the intrusion of moisture into the hair from a humid environment. Additionally, these ingredients typically coat, flatten, and seal the external cuticle layer of the hair strands. The anti-humectant ingredient will most likely be higher on the list of ingredients, and may be problematic for those on a shampoo free routine.

In many formulations, the ingredients used for this anti-humectant task are silicones. This is because they not only perform the anti-humectant duties in a superior manner, but they also provide excellent lubrication of the hair and add a high degree of gloss (shine”>. Esters (such as isopropyl palmitate”> are another category of ingredient used for their water-resistant properties in products designed to function well in high humidity climates. There are also many natural ingredients that work well for this purpose, such as hydrogenated castor oil, beeswax, and plant triglycerides such as coconut oil, palm oil, olive oil, and shea butter. I have included the ingredient lists for a couple of different hair pomades and anti-humectant products that I found interesting.

Hair Pomade by John Masters Organics

Ingredients: Extra virgin olive oil, organic beeswax, mango butter, babassu oil, jojoba, wheat germ oil, pure essential oils of bay laurel, cedar atlas, fir balsam and massoia, vitamins A, C & E. Certified Organic Ingredients.

Aveda Brilliant Anti-Humectant Pomade

Ingredients: Caprylic/Capric Triglyceride; Isopropyl Palmitate; C18-36 Acid Triglyceride; Bis-Diglyceryl Polyacyladipate-1; Bis-Diglyceryl Polacyladipate-2; Castor (Ricinus Communis”> Oil; Phenyl Trimethicone; Cyclomethicone; Fragrance (Parfum”>; Glyceryl Laurate; Rice (Oryza Sativa”> Bran Oil

How to style curly hair, depending on the dew point

It would be great if there were a magical mathematical formula to tell you exactly which ingredients to use in which temperature and humidity conditions. The best I can do is provide you with some loose recommendations on that topic. As always, you will need to do some experimentation with your own hair to find the combination of conditions and product that give the results you prefer.

Dew points below 35°F

If the dew point is below 35°F or so, the moisture content in the air is sufficiently low that a humectant applied to your hair might be irresistibly drawn to the moisture in your hair and make every attempt to steal it from you (by drawing it out of your hair and binding it to itself”>. This can result in dry, fly-away hair, split ends, and broken strands. This effect can often be compensated for by using plenty of moisturizing products, not over-drying your hair (leave it somewhat moist after washing”>, and layering leave-in conditioners with humectant-containing styling product.

Dew points from 35°F to 60°F

Curly hair seems to really thrive in moderate climactic conditions, and dew point ranges of approximately 35°F to 50°F seem to be optimal. In this type of weather, most curlies find that they can get really pleasant results by using products that contain some humectants. There is just enough moisture in the air that the humectants can grab a little from the environment, which can enhance the curl and create a bouncy feeling to the hair.

Dew points of 60°F or above

When the dew point for your area is at 60°F or above, it might be a good idea to apply some product with anti-humectant properties. These products will seal the hair shaft, flatten the cuticle and prevent atmospheric moisture from absorbing into the interior of your strands. Most of these products will contain ingredients that are water insoluble. However, many of these products contain ingredients which are easily removed with an extremely mild shampoo or perhaps even a thorough conditioner wash.

The key to having the best curls in any weather is to have extremely well-hydrated and moisturized hair. This will protect your hair from losing too much moisture in dry weather, and it will prevent your hair from absorbing excess moisture in humid conditions. Another important factor is the overall condition of your hair. Hair that is damaged will necessarily be more porous, and thus more susceptible to climactic conditions. Smooth strands with a sealed, flat cuticle layer will be naturally more impervious to atmospheric conditions as well.

What Polyquats Do to Curly Hair, According to an Expert

Polyquaternium ingredients are a popular topic in curl-community discussions, where they are a frequent source of concern and confusion. Unfortunately, very little generalization can be accurately applied when it comes to this category of ingredients. While all polyquats share certain specifics in common (they are polymers with multiple sites that carry a positive charge“>, there is a huge degree of variation in the polymer structure, molecular weight/size, and charge density for the many different species.  Each is sufficiently unique that it warrants individual consideration as to its characteristics and performance as a component of a hair care product. One interesting example of this is polyquaternium-69 (AquaStyle™ 300, by ISP”>, which is used as the primary hold agent in a number of styling gels and foaming mousse products such as Jessicurl Extreme Hold Spiralicious Styling Gel and Göt2b Ultra Glued “Invincible” Styling Gel.  It is touted as providing superior performance and super strong hold. So what differentiates this polymer from other polyquats?

What is a polyquat?

Polyquaternium is a word used to describe a category of materials used in cosmetic formulas. They are polymers (large molecules made up of repeating units of the same base block or blocks, called monomers”> that have positively-charged sites repeating along the length of their structure in a variety of configurations. They are often used as conditioning ingredients or as ones that enhance curl or give hold to spiked styles.

You may recall that the positively-charged sites along the length of polyquats are attracted to negatively-charged sites on hair and skin, which allow them to deposit onto the surface and cling to it pretty tenaciously. In hair, the quantity of these negative sites increases with damage from sun, heat, and chemical processing, with the result that polyquat conditioning and styling agents can attach to many sites on the surface of damaged hair. The more damaged the cuticle is, and the higher the charge density of the polymer, the stronger the association will be between the polymer and the hair, resulting in very effective conditioning and curl retention. However, this can also make some polyquats very difficult to remove from the surface of hair, and in some cases can lead to buildup and negative effects.

What makes PQ-69 special?

Limitations in the properties of various iterations of vinyl acetate, acrylates/acrylate copolymers and polyvinylpyrrolidone have long challenged formulators to produce combinations that provide sufficient hold without flaking, that can maintain curl retention in high heat and humidity conditions, and that are easily removable from the hair. For this reason, synthetic polymer chemists strive to produce new polymers with properties that exceed those currently in use. Polyquaternium-69 is one such polymer, and it is exceptional in that it conquers many of the problems inherent in the more traditionally-used polymeric systems used to provide hold in hair gels and mousses. Each of the four components in this tetra-polymer was selected for the specific properties it would impart to the final performance. It provides an ultra-strong, yet more durable and lasting hold, as well as a number of other benefits.

For those interested in the specific chemical structure of polyquaternium-69, it is a tetrapolymer of vinyl caprolactam, vinyl pyrrolidone, dimethylaminopropyl methacrylamide (DMAPMA”> and the quaternized, alkylated DMAPMA, from which it derives its cationic nature. Its structure can be seen here.

Improved removability

Compared to other polyquats, PQ-69 has a relatively low number of cationic (positively-charged”> sites, and like the other polyquats, it is water soluble with fewer ionic sites per molecule. The polymer does not adhere as tightly to the surface of the hair, which means it is suitable for all types of hair and should be easily removable with most methods of cleansing. Water-only or vinegar-only methods may not be sufficient.

curly hair products with polyquaternium

Humidity resistance

Despite its ionic nature and solubility in water, the hydrophobically modified portion of this polymer means that PQ-69 acts as a water-repellant, hydrophobic layer on the hair surface. This enables it to prevent moisture absorption from the air, so it can exhibit amazing curl retention, even when hair is exposed to high humidity for very long periods of time. How many curlies would love to have a product that could make such a promise?

In a laboratory test where samples were subjected to temperatures of 80°F and 90% relative humidity, locks of hair treated with a control gel comprised of standard polymers (PVP & VP/VA”> were compared to locks treated with a PQ-69 gel. The samples treated with the commercially-available product were found to exhibit failure of curl retention after one hour, while the PQ-69 product maintained its hold at 90% after 24 hours. Similar tests were done to evaluate frizz, and again, the PQ-69 sample performed extraordinarily well.

Luxurious shine

PQ-69 forms a film around multiple strands of hair and helps hold them all in the desired alignment. This film also increases the contrast between light and dark areas on the hairs, and increases intensity and coherence of light scattering. The result is that it gives hair increased radiance and gloss.

Super strong, durable hold with no flaking

The vinyl pyrrolidone monomer in PQ-69 allows it to form a very stiff film upon deposition onto the cuticle surface. This stiff film helps set up the curl or style and fixes it into place. Initially, this can feel quite stiff and crunchy to the user, which some people enjoy. However, oftentimes these stiff-hold polymers are also very brittle, and if the hair is touched or manipulated in any way, the polymer film breaks, flakes off most unattractively, and the style is lost. But with the unique structure of PQ-69, the vinyl caprolactam monomer adds flexibility and elasticity to the film.

Mechanical testing done on various samples showed that the polymer films can undergo a good bit of loading without breaking, and that they do exhibit some signs or permanent deformation (meaning they don’t bounce back completely, like a rubber band might do”>. As a result, curl retention is maintained, even if you touch or scrunch your hair, and best of all, no unsightly flaking occurs. Styles achieved with this polymer seem to tolerate being scrunched to work out the crunchiness and stiffness, and yield tight, bouncy curls afterward.

Take-home message

In summary, gels and other styling products made with specialty polymer, polyquaternium-69 will provide a very strong hold.  While this may feel too stiff and crunchy initially, it can be scrunched out to achieve soft, very bouncy curls.  The gel does not flake, even when hair is combed or brushed. It is highly resistant to moisture and can hold even the most radical styles and curls for long periods of time in hot, humid conditions. It lends itself very well to second, and dare I say, even third-day hair, because it really helps the hair retain its shape. The shine produced is perhaps not as glossy as that produced by amodimethicone, but it is still very noticeable and nice.  The ease of removability due to its limited ionic nature means it is safe for almost all cleansing regimens.

On a personal note, I tried some of my husband’s gel (Göt2b Ultra Glued Styling Gel”> the other day, because I was out of my own.  While initially annoyed at the tremendously strong and crunchy texture, I have been pleasantly surprised at how nice the curls and shine have been since gently scrunching my hair. The style has actually held up very nicely for three days, even in the ridiculously hot and humid conditions here in Florida! I have not enjoyed the tactile feel of my hair with this product though, but I think that is simply because two of the other ingredients in it don’t usually work well for me. I plan to purchase the Jessicurl product (Spiralicious Styling Gel”> immediately, to continue my experiments with this polymer.

This Is What You Need to Know About Magnesium Sulfate

What is magnesium sulfate?

Magnesium sulfate, also known as Epsom salts,  is an ingredient often touted as a natural curl booster or curl activator for hair.

It is typically used in leave-in conditioners and curl enhancers, both commercially available and homemade, and it is applied via a spray-on delivery method.

When you use products that contain magnesium sulfate you may find that your hair is curlier and bouncier on day one, but with repeated use, later in the week your hair may feel dry and hard to work with.

What curlies say

NaturallyCurly members are extremely astute when it comes to ingredients and their hair. Reader Sophiemol_ asked in our CurlTalk forum:

Why does magnesium sulfate make my hair curl so well?

I just wish it didn’t dry out my hair so darn much…I’ve been playing around with using it over top of [SheaMoisture] and with other massively moisturizing products, but it doesn’t seem to be counteracting the drying…

By understanding the protein structure of curls and how magnesium sulfate interacts with it, we can gain a better understanding of why magnesium sulfate enhances curl pattern and retention, and also why the effects seem short-lived and eventually become unpleasant.

What makes hair curly?

Hair is comprised of keratin protein, a polypeptide particularly differentiated from other proteins for its large proportion of cysteine, a sulfur-containing amino acid.  These polypeptide strands are crosslinked (bound together into a three-dimensional network”> via formation of covalent bonds between adjacent cysteine residues. This linkage is a chemical crosslink referred to as the disulfide bond, and is the source of the strength and physical configuration of the hair. As the degree of disulfide crosslinking in a strand increases, so does the amount of curl in the hair. 

As the degree of disulfide crosslinking in a strand increases, so does the amount of curl in the hair. 

Crosslinking also occur between the polypeptide chains, and they also contribute to the structure of the hair. These two additional types of crosslinking are achieved via hydrogen bonding and formation of salt bonds and are sometimes referred to as secondary bonds. However, both of these types are physical crosslinks, rather than chemical ones (imagine it as two strands taped together or two magnets attracted to one another versus two strands sewn together or melted and re-formed into one object”>, and are susceptible to disruption via mechanical forces (touching or brushing the hair, wind”> or the presence of water (swimming, washing, humidity, rain”>. Perms enhance curls by breaking the disulfide bonds via chemical means, curling the hair tightly to physically restructure it, and then re-forming the disulfide bonds at a higher percentage.

What does magnesium sulfate do?

Several researchers have found that hair is stronger and curl retention is increased when magnesium sulfate is incorporated into the rinsing and neutralizing agent used to re-form the disulfide bonds. They also noted that its use enhanced the curl pattern and imparted a greater stability to high humidity.

Magnesium sulfate is an inorganic compound that exists as a hydrated material, magnesium sulfate septahydrate (MgSO4• 7H2O”>. This salt is extremely hydrophilic and thus easily dissolved into an aqueous solution that can be spritzed onto the hair. It attracts and binds water molecules from its surroundings to itself.  When MgSO4 is applied topically to hair it does not affect the covalent disulfide bonds, but it does impact the physical crosslinks formed by hydrogen bonds. By increasing the number of hydrogen bonds, the Epsom salt tightens the curl pattern of the hair.

How does magnesium “activate” curls?

The mechanism by which magnesium sulfate achieves this curl activation consists of two steps:

  • First, the magnesium neutralizes the excess negative charges on the surface of the keratin and brings it to its ideal pH (also known as its isoelectric point”>.
  • Secondly, a dehydration mechanism via a salt-protein interaction increases the quantity of hydrogen bonds (physical crosslinks”>, which makes the hair curlier.  This second part is what is critical to understand.

Why does magnesium sulfate make your hair feel dry and rough?

Hair keratin protein incorporates water into its structure. This moisture gives it softness and pliability and is why we strive to maintain properly hydrated hair. However, in a highly hydrated environment, the formation of hydrogen bonds between adjacent cysteine amino acids is minimal. But, in the presence of the highly hygroscopic salt, MgSO4, the keratin protein becomes dehydrated. This dehydrated environment is what permits the formation of additional hydrogen bonds and the curl activating properties of magnesium sulfate. Thus, the very quality that permits magnesium sulfate to boost curl formation is also the one that generates the poor results in subsequent uses.

Magnesium sulfate also forms fairly large crystals, and these structures can roughen the surface of hair, yielding an unpleasant texture and tactile experience for some. They may increase tangling as well, if adjacent hair strands get caught on them. For this reason, it is advisable to use a good lubricative leave-in conditioner along with a magnesium sulfate. (Dare I say it? A silicone might work nicely and not interfere with the curl forming effects of the MgSO4″>.

What about magnesium oil?

Some products are beginning to advertise that they use magnesium oil, rather than magnesium sulfate.  These are typically a supersaturated aqueous solution of magnesium chloride (MgCl2″>. The chlorine molecule changes the properties of the salt, rendering it slightly less hydroscopic. For this reason, it may not boost curl as significantly, but also will not dehydrate and potentially damage the hair as much. It seems a reasonable type of product with which to experiment.

How to use magnesium sulfate safely

Magnesium sulfate can indeed be a useful curl activator or curl booster and has a place in the arsenal of every curly girl (or guy”>.  However, the mechanism by which it achieves this effect leaves hair, especially fragile curly hair, very vulnerable to damage due to dehydration.  This effect can be minimized by using magnesium sulfate infrequently as an emergency agent, or using it in conjunction with products that deeply moisturize and protect the hair.  CurlTalk member Jas76 says that “a good LI [leave-in conditioner] under it helps, and then scrunching in some light oil after it’s dry helps, too!! And yes – don’t use it everyday if you find it particularly drying.” We also recommend that you condition very well after every use.

This article was originally published in 2013 and has been updated for grammar and clarity.

Here’s Everything You Need to Know About Porosity
Porosity is the term used in the science of hair care to describe how easily water and other matter can diffuse back and forth through the cuticle layer and into or out of the cortex.
photo courtesty of Pavel Rodlmov – Getty Images

Hair is much like a sponge, capable of absorbing water and other substances from the environment; it is also susceptible to losing precious moisture and lipids to the environment. Maintaining an optimal balance of moisture in your hair preserves its elasticity. This is especially important for those of us with curly hair, as it greatly influences the health and beauty of our curls.

The individual scales of the cuticle overlap one another much like the feathers of a bird or scales on a fish.

This amazing system allows diffusion of oils and moisture into and out of the hair, as needed. Porosity is determined by how tightly the cuticle scales adhere to the surface of the hair shaft and also by how thoroughly adjacent scales overlap one another.

Low Porosity

  • Hair described as having low porosity is characterized by a tightly bound cuticle layer where the individual cuticle scales lie flat and overlap one another.

Low porosity hair is quite shiny, especially if it is a darker color. This porosity is considered to be healthy. If your hair repels water when you attempt to wet it, that is a good indication that it has low porosity. It is difficult to chemically process because of its resistance to penetration. It is prone to an excessive accumulation of protein if deep conditioning products are used, and feels stiff and straw-like. High porosity curls require products that are rich in moisture and emollients; they also benefit most from products that contain humectants that attract and retain moisture to the hair.

If hair with very few or very small openings becomes dry for some reason, it can be difficult to restore the proper moisture balance to it. In this case, a deep conditioning treatment with moderate heat would be a good way to ensure the cuticle is sufficiently opened up to allow moisture to enter into the cortex.

Normal/Medium Porosity

  • Hair possessing to hair with this level of porosity generally requires the least amount of maintenance.
Normal porosity hair allows moisture to pass into the cortex as needed, but resists permitting too much water to penetrate. Repeated works by various research groups have found that healthy hair of average porosity can absorb water up to a maximum of 31.1% by weight. Normal porosity hair has a tendency to hold styles well. Perming or coloring can be done in a predictable manner, following the usual guidelines of the product. However, one must note that these processes will damage the hair and increase its porosity over time. An occasional deep conditioning treatment with a protein-containing product will be of benefit, but proteins should not be included in the daily regimen.

High Porosity

  • Chemical processes, harsh treatment, and environmental exposure are all responsible for causing cumulative, irreversible damage to the cuticle layer.

High porosity is a result of damage to the hair that creates gaps and holes in the surface of the shaft. Hair with this type of uneven, pitted and rough surface is prone to damage resulting in a cascade of effects that culminate in unmanageable and unlovely locks.

Hair with a great deal of porosity has been found to be capable of absorbing significantly higher amounts of water than hair or normal or low porosity (up to 55%, in contrast with 31.1% for healthy hair”>. Excessive absorption of water from the atmosphere causes frizz and tangling on humid days. Total immersion of high porosity hair during bathing, swimming, or shampooing can lead to significant breakage due to loss of elasticity from the sheer weight of the water absorbed. It also takes on color much more quickly and in higher concentrations than normal porosity hair when undergoing a chemical color process.

Curly girls with high porosity hair should use products with lots of moisturizers and emollients and also use anti-humectants in high heat and humidity climates in order to seal their cuticle against excessive absorption of moisture from the air. Protein treatments can also be helpful for patching some of the holes in the hair. However, it is important to follow up with moisturizers in order to avoid a stiff texture. Rinsing with a slightly acidic rinse will help flatten and seal the cuticle.

Genetic or Biological Contributors to Porosity

photo courtesy of Pete Collins – Getty Images
  • Genetics and curl pattern contribute to how tightly the cuticle layer adheres. Some people have a circular hair shaft, which is optimal for cuticle scales to lie flat and overlap one another, resulting in low porosity.

Other types of hair are more elliptical or even flat and ribbon-like. This geometry doesn’t allow for all of the cuticle scales to lie flat and overlap one another along the axis of the hair. This creates areas of discontinuity in the cuticle layer, adding porosity to the hair.

Curly hair has a tendency to be naturally higher in porosity than straight hair. This is because the spirals in the helical configuration of the curls create areas where individual cuticle scales are raised slightly away from the longitudinal axis of the hair. The curlier the hair is, the more breaks you have in the smoothness of the surface, so the porosity is invariably increased.

External Contributors to Porosity

  1. Environment: Exposure to UV rays for prolonged periods can fuse cuticle scales together, which inevitably leads to further damage of the cuticle layer. It is a good idea to cover your hair when in the sun or use products which contain sunscreen agents.
  2. Chemical Processing: Perms, relaxers, and coloring processes all require the cuticle to first be opened via application of an alkaline solution. This allows the chemicals to access the interior of the hair shaft in order to make permanent changes to the structure of the proteins that are the building blocks of the hair. All of these processes are capable of doing permanent damage to the cuticle layer. This damage builds up with repeat use of the chemical process. Bleaching is the most damaging process, followed by perming and relaxing, with most permanent coloring processes being the mildest.
  3. Heat treatments: Heat from a blow dryer, flat iron, curling iron, or hot curlers can all cause irreparable damage both to the cuticle and the cortex of the hair. These tools can heat water inside the hair past the boiling point and cause the hair to rupture from the inside out. It is not difficult to see how this could increase porosity.
  4. Mechanical Damage: Combing, brushing, and friction from scarves, and hats, and scrunchies all cause damage to the cuticle layer. Over time all of these can result in torn and ripped cuticles, thereby increasing the porosity of the hair. Curly hair should only be combed with a wide-tooth comb while it is wet and coated with a conditioner for maximum slip. This minimizes friction and subsequent damage to the scales.
  5. Shampooing with sulfates and soaps: The cuticle layer is comprised not only of keratinous scales, but also a layer of fatty acids on the top surface that protect the hair from moisture, as well as a layer beneath the scales called the cell membrane complex (CMC”>. This acts as a cement the keep the cuticle scales firmly attached to the hair. A large portion of this CMC is made up of a lipid layer of mixed fatty acids, including 18-methyleicosanioc acid (18-MEA”>, stearic acid, and palmitic acid.
How Hair Products Are Made to Look "Pretty"

In the curl community, lots of energy is invested into analyzing the performance of hair care products. And while most consumers probably give little thought to the appearance of their holy grails, they are definitely influenced by this seemingly irrelevant property.

Not surprisingly, product formulators spend a lot of time optimizing products to make them visually appealing to a consumer. The incorporation of pearlizing agents, opacifiers, and artificial colors are all methods used to create products that give the visual impression of luxury.

Why products get a “cosmetic enhancement”

Shampoos and conditioners are mixtures known as oil-in-water emulsions. The major component is water, with various types of surfactants, emulsifiers, and oil-phase components dispersed into the aqueous phase via formation of micelles. Oftentimes, the concentration of non-water soluble ingredients is sufficiently high to render the micelles larger than the wavelength of visible light. This causes light to be scattered, creating a cloudy solution. Hazy solutions are not regarded as appealing by most consumers, as they can give the perception of not being clean or pure.


Another potentially unpleasant phenomenon is that certain useful ingredients can impart a yellow or amber hue to the finished product. This subtle discoloration can make consumers uneasy, as that color is often associated with spoilage or rancidity. A bright white or creamy ivory colored product is generally rated as cleaner and more attractive.


It is the goal of formulating chemists to create a product that appeals to all of the senses of their consumers, so they take definite measures to make their products more visually attractive. Happily, the solutions developed are not only capable of masking cloudiness or yellowing, but can also yield a highly pleasing final product.

The techniques formulators use to improve a product’s appearance

One technique popular in the 1970’s was to cover any yellow or amber hues by using enough blue and/or green dye to create a blue or green product. These were not natural-looking and often fairly runny in consistency.

Earthy tones for natural product

Current approaches seem to favor the use of only enough color to counteract the yellow and create a white or ivory product. Another way is by using a mixture of red, blue, and yellow dyes to create a brownish products that remind the consumer of clay or earth.

Opaque, white, and thick consistency for cleansers and high-end product

An additional method to overcome hazy solutions is to incorporate opacifiers into the formula. These materials create a homogeneous, solidly opaque appearance to the shampoo or conditioner. Dow markets a line of polymers intended for this use, and the marketing materials say they create a “rich, creamy look, with a dense uniform opacity.” The use of polymers also helps to increase the viscosity of the system, which consumers also interpret as thick and luxurious.

Dow has several different polymers available for this purpose, each specially synthesized to be compatible with different common systems. Ethylammonium chloride acrylate/HEMA/styrene copolymer is cationically charged and is compatible with most cationic conditioning products. They also have an anionic opacifier for use in shampoos, soaps, liquid hand soap, and body washes, all of which traditionally rely upon anionic surfactants for cleansing purposes.

A nonionic version is sufficiently flexible to be incorporated into a variety of types of formulations, and is especially useful in silicone-containing formulae. These types of materials make bright white shampoos and conditioners that are creamy and thick.

How products get their “luster”

Perhaps a favorite method for overcoming problems with cloudiness and yellow hue in personal care products is to use pearlizing agents. These materials not only act as opacifiers, but also impart an iridescent luster to a product that is considered to be highly attractive to consumers.

This look can be achieved by using naturally-occurring minerals such as marine aragonite powder (real pearl”> or titanium oxide-coated mica particles, but more often is achieved via use of synthetic fatty acid ether esters. The synthetic esters most often used are ethylene glycol distearate (EGDS”> and ethylene glycol monostearate (EGMS”>. Others are PEG-8 dioleate, myristyl myristate, ethylene glycol dipalmitate, and other esters. These materials crystallize in solution into flat platelets that have a very high refractive index. Optical interference from these platelets creates a pearlescent appearance in products containing these materials.

The drawback of using pearlizing agents

One drawback to using materials such as EGDS is that the somewhat tricky process for adding them during manufacturing. Temperatures must be elevated above the melting point of the EGDS. In order to obtain the highest quality pearlescence, the crystallization process must be carefully controlled, which means that the mixing rate and forces must be carefully monitored, and the rate of cooling must also be very controlled. Crystals of just the right size,  and of the smoothest, most regular shape provide the best, most lustrous appearance.  This can be costly and troublesome.

Considering storage and shelf life

Chemical suppliers are vying for market share for these types of relatively simple-to-make ingredients. One way they seek to differentiate themselves is to provide blends that contain these pearlizing agents already dispersed into surfactant-containing mixtures. These blends have varying features to recommend them, depending upon the package, but typically, the most valuable feature is that they can be processed at cold temperatures and require much less oversight of the manufacturing process to develop the optimal crystalline structures. They are also often times more stable in typical storage conditions. Ease of processing reduces costs for the manufacturer, which translates into these pearlized products being more affordable for the consumer.

These materials can have some slight moisturizing properties for hair or skin. Generally though, they are not going to significantly impact the performance properties of your favorite shampoo or conditioner. Most opacifiers and pearlizers have sufficient polar or amphiphilic character as to be easily removed from hair (if they remain on the hair in the first place”> via a conditioner wash or mild shampoo cleanse.

Next time you shop for hair products, think about this…

So the next time you pick up a product, in addition to considering its performance and fragrance, take a moment to ponder and appreciate its appearance as well. A bunch of scientists somewhere put a lot of time and thought into making it attractive to you. It is an important part of the whole package.

This article was originally written and published in 2012 and has been updated for clarity.

The Secret Science of Hair Gel, Revealed

We see the brightly colored packaging in the aisles and watch the glossy ads of women with larger than life hair say you can have “75% more definition!” – but what is really going into your hair products? What makes a good gel different from a bad gel, and what is that thick, sticky liquid actually doing to your hair? Cosmetic chemist Tonya McKay breaks down the science of hair gels for us, so that what you spend your money on and put on your body is no secret to you.

Before you try one gel and make up your mind about gels as a whole, understand that the properties of hair gel are highly dependent upon its formulation (which ingredients are present and in what composition”>, your hair type, the other products in your hair, and the climate in which you live. 

Why use styling products?

A styling product helps to provide shape and hold to a style by forming a film on the hair that creates physical bonds between adjacent strands, holding them in place. One method of achieving this is spot welding, where droplets of product are applied at critical junctures and hold the hair in place. Hair sprays perform in this manner and are useful in providing hold to hair.

Another method of creating hold is known as seam welding and involves the application of a product down the length of the hair shaft, which facilitates formation of physical bonds between adjacent hair strands. This creates the clumping effect so often desired by people with curly hair. These types of products also impart volume to the hair by increasing stiffness from the root, which lifts it away from the scalp. Gels, hair crèmes, waxes, and mousse provide hold via the seam welding mechanism. This type of hold is very susceptible to disruption due to physical manipulation, such as combing, touching and windy conditions.

So, what is a gel?

A gel is a colloidal dispersion of particles (ranging from nanometers to micrometers in size”> in a liquid medium. The solid particles (oftentimes polymers”> form a network throughout the liquid that swells and forms a jelly-like mass. Gels are comprised mostly of liquid, but can appear like solids when at rest. The application of force allows these gels to flow like liquids, which makes them useful for many applications, such as hair care products. In a hair gel, the product has a thick consistency in the bottle, but should come out of the container easily and spread evenly on the hair. As product is applied, the polymers deposit onto the surface of the hair and cause adjacent strands to be attracted to one another through capillary forces, creating clumps of curls.

As product is applied, the polymers deposit onto the surface of the hair and cause adjacent strands to be attracted to one another through capillary forces, creating clumps of curls.
Water evaporates slowly from the hair, and the polymers dry to form clear films. These solid films help maintain curl and shine until the bonds are either broken via mechanical forces (combing, touching, windy conditions”> or until the product is removed by washing.

The composition of a hair gel:

  • water as the main ingredient
  • polymers for film-forming
  • emulsifiers for non-water soluble components
  • viscosity modifiers (thickeners, such as carbomer”>
  • fragrance
  • preservatives
  • additives used to impart moisture, shine, and UV protection, and to modify the properties of the film that is formed

Modification of the film properties of hair gels is the subject of continuing research and development, both at the academic and corporate level. The reason for this lies in the fact that no current polymer or combination of polymers provides the perfect set of properties. Some polymers provide excellent hold, but are too brittle and can cause flaking or style disruption throughout the day. Others may get around the problem of being brittle, but may be susceptible to moisture and cause frizzy or dull hair in humid environments. Still others may provide all the desired hold and shine properties and be indifferent to climate, but may be difficult to remove with shampoo and can cause unattractive build up problems. It is also desirable that a hair gel maintain its properties over a broad range of temperatures, which can be another difficult obstacle to overcome.

Hold Agents

Some of the more frequently used polymer fixative agents include, but are definitely not limited to, the following:

  • PVP (poly N-vinyl-2-pyrrolidone”> is an excellent film-former that is substantive to hair, forms clear films, and is completely water soluble. However, it absorbs water readily, which in humid weather makes it sticky or tacky to the touch, can cause frizz, and give a dull appearance to the hair. In dry weather, it can become brittle and flaky.
  • PVA (polyvinyl acetate”> resists absorption of water in high humidity (which leads to better hold in damp weather conditions”> and is more flexible in dry weather so it doesn’t flake, but is not as substantive to hair.
  • PVP/VA copolymer provides an excellent compromise between the properties of each of these polymers individually.
  • Polyurethane (good thermal stability”>, acrylic copolymer, polyacrylates, acrylates copolymer, and other copolymers are also all hold agents found in hair gels.
  • Cationic polymers (Polyquaternium”>: These positively-charged polymers are very substantive to the negatively-charged surfaces of human hair. For this reason, some cationic polymers have been found to be useful in hair styling applications. They form clear, glossy films and decrease static-charge buildup and fly-away hair. They typically provide good wet and dry combing results and impart a smooth feel to the hair.
  • Polyquaternium-4: is a superior film-former on the hair, and has been found to exhibit very high curl retention even in humidity. It is very substantive to hair, but exhibits little build-up. It is very stiff due to its molecular structure, and is thus outstanding for use in hair gels.
  • Polyquaternium-11: is copolymer of VP/DMAEMA (vinyl pyrrolidone and dimethylaminoethyl methacrylate”>. As a copolymer of VP and an acrylate, it is less susceptible to humidity than VP homopolymer. However, it may have more potential for failure due to humidity than polyquaternium-4. Polyquaternium-11 is generally recommended for mousses and creams, where it can moisturize as well as aid in styling. This polymer is water miscible, but not water soluble. This could lead to some build-up over time if one were not using a clarifying shampoo occasionally. There are many more polymers, copolymers, combinations of polymers, and new additives for hair gels that are being used in commercially available formulas, and even more being developed in laboratories. Many of these provide better rinsability, more softness, and a tougher film with better hold. We may explore some of these newer ideas and technologies in a future article.

To sum it up

If you live in a humid, hot environment, you should avoid a product containing PVP as an ingredient. If you are in a dry, cold climate, you should seek a product with Polyquaternium-11. Humectant additives–panthenol, propylene glycol, glycerin–may help product performance in a dry climate also, but may be disastrous in a humid one. As always, experimentation will be necessary to find the product that is right for you and your hair.

This article was originally published in January 2008, and has been updated for grammar and clarity.

Polyquaternium-59: Sun Protection for Your Curls

Photo Courtesy of Natasha Lee

Polymer scientists continually collaborate with cosmetic chemists and formulators to develop new molecules designed to overcome limitations that exist with currently available ingredients. One example of such work is Polyquaternium-59 (Crodasorb UV-HPP”>, a cationic polymer which is now being used in a number of commercially-available skin and hair care formulations, including some products by Ouidad. Since the structure, function, and performance of the polymers in this category can vary so widely, as each is specifically tailored to meet a targeted need, it is worthwhile to take the time to examine this particular polymer to gain an understanding of its potential benefits to both the consumer and the chemist in a formulation.

What is it?

Polyquaternium-59 is a polyester molecule that has quaternized ammonium sites (positively-charged”> along both its backbone as well as in pendant groups attached to the chain.

(IUPAC name: Poly(20,25-dioxo-2,5,10,15,18-pentamethyl-10-(2-hydroxy-3-(3-(3-phenyl-2-propenamido”>propyldimethylammonio”>propyl”>-10-azonia-1,4,7,13,16,19-hexaoxapentacosanediyl”> chloride”>

Compared to many cationic polymers, it is of relatively low molecular weight, averaging 5000 grams per mole, and according to the manufacturer, Croda, it is 65% active, which means it has a high level of charge density relative to other polyquaternium materials used in cosmetic applications. This enhances the water solubility of these polymers and also increases substantivity to hair, and thus improves conditioning properties. The high degree of water solubility also means this polymer is suitable for cold mix processes, which is appealing to formulators from both a cost-saving perspective and from an environmentally friendly manufacturing paradigm. [i]

The novel twist to the polymer structure in PQ-59 is the inclusion of groups capable of absorbing UV radiation at the ends of the pendant groups. (For those interested in the specific organic chemistry, these groups are a carbonyl group conjugated diene/ aromatic moieties “>. These portions of the molecule transform the harmful, high energy UV radiation into a lower energy form (infrared”> that is emitted as heat. This sun protection quality is perhaps the most valuable contribution this polymer makes to any personal care product formula.

Sun Protection for Hair

The surface of human hair is highly hydrophobic, which helps to seal moisture into the hair shaft, protect it from the environment and mitigate effects from fluctuations in humidity that can cause structural damage.

Exposure to ultraviolet radiation occurs whenever we go outside. We are all well aware of the importance of limiting skin exposure to these harmful rays, but it is less well known the extent of damage they do to hair as well. UV-B radiation (280-320 nm”> cleaves disulfide bonds (S-S”> in the cuticle, depletes cystine in the structure, and thus damages the protein structure of the protective cover of the hair strand. This increases surface roughness and porosity, which results in frizz, tangling, and ultimately, breakage. Breakage of disulfide bonds can also lead to frizz and unmanageability as it disrupts curl structures. [ii]

UV also depletes the protective lipids found on the surface of the cuticle. This increases combing forces necessary to detangle hair, which generally results in formation of split ends and breakage.

The surface of human hair is highly hydrophobic, which helps to seal moisture into the hair shaft, protect it from the environment and mitigate effects from fluctuations in humidity that can cause structural damage. UV-B breaks down tryptophan found in the protein structure of the hair and creates a more highly negatively charged surface, which becomes more hydrophilic and less capable of moisture retention and more susceptible to ill effects from the environment.

Ultraviolet radiation also penetrates into the cortex of the hair where it breaks down protein structures within the hair strand as well, compromising the mechanical integrity of the hair. This results in a lower tensile strength for the hair, and so it breaks more easily. UV-A radiation in the cortex reacts with both natural melanin pigments and chemical dye molecules, causing photobleaching and yellowing, both definitely undesirable effects.

Clearly, protecting hair from damage from ultraviolet radiation is a desirable goal, for health, strength, luster, color retention and overall beauty of our tresses. This is especially true for longer hair, as damage is cumulative. Since wearing a hat everywhere does not seem like a fashionable solution, chemists and formulators have been experimenting with different ingredients for a while. Some of the limitations of common sun protective ingredients in current use are that the smaller molecules are not very substantive to hair, and they are often very greasy. For this reason, polyquaternium-59 was developed to overcome some of the deficiencies of other options. Its greater charge density as a cationic polymer enhances its substantivity to the surface of hair, which carries a slight negative charge. Also, as a lighter weight, water-soluble polymer, it has no greasy tactile sensation.

Read More: The Best Vitamin for Hair Growth?

Measuring Performance

PQ-59 has been found to mitigate damage caused by ultraviolet radiation and produces excellent results by preserving hair’s natural hydrophobicity, maintaining fiber tensile strength, and reducing combing forces. The synergistic combination of both substantive conditioning polymeric properties and UV-absorbing properties has the potential to create a uniquely effective molecule.

Many ingredients and products carry bold claims, but it can be difficult to determine true efficacy of the material. Fortunately the manufacturers of this polymer have done a large amount of scientific testing to evaluate the performance of PQ-59. It is important to keep in mind that with a vested economic interest in the success of the polymer, they are not unbiased, and thus the procedures, data and conclusions should be examined closely and with some degree of skepticism.

A variety of quantitative testing techniques were used to determine the ability of PQ-59 to provide protection from harmful UV radiation. Hair was treated with a 2% polymer solution in SLES (sodium lauryl ether sulfate”> and run against untreated hair and hair treated with small molecule uv-absorbers. All hair was tested before and after a dose of exposure to UV radiation equivalent to eighteen days.

The claims were substantiated by the following results. Dynamic contact angle experiments showed a (statistically significant”> higher degree of retained hydrophibicity on the surface of the hair compared to hair treated with a small molecule. Measurement of tryptophan levels at the surface via fluorescence spectroscopy revealed higher levels of retained tryptophan in treated hair versus untreated hair. Mechanical testing showed a five percent increase in tensile strength for irradiated hairs that had been treated with PQ-59 compared to untreated hairs. Scanning electron microscopy imaging of the cuticle showed a smoother, more intact surface for hairs treated with the polymer. Finally, spectrocolorimetric evaluation demonstrated increased color retention in fibers treated with the polymer. Third party visual inspection and comparison of treated versus untreated tresses also concluded that PQ-59 improved color retention after prolonged UV exposure.

The data certainly seem to support that this polymer can effectively mitigate damage caused to hair by exposure to ultraviolet radiation. It also does not appear to be necessary to use large quantities of the polymer, as 2% seems to provide significant benefit, even in a rinse-off product. It would be beneficial to see data run by an objective third party, but oftentimes, finished goods manufacturers do not make their data available to the public.

Notes for Curly Hair or No-Shampooers

Curly hair is especially susceptible to anything that could cause damage to the protein structure of the hair. For this reason, protecting it from environmental damage is essential, which includes limiting ultraviolet radiation exposure. PQ-59 seems to be an ingredient that can be quite useful for this purpose and is currently being incorporated into products with increasing frequency.

Polyquaternium-59 is extremely soluble in water, alcohol and glycerin. It is also very soluble in surfactant-containing mixtures, such as SLES, SLS, ALS and presumably cocamidopropyl betaine (although no specific data were found regarding the betaine”>. It also has a relatively small molecular size relative to other polymers used in hair care applications. So, while the positively charged polymer is substantive to the surface of the hair via electrostatic interactions with the negative charges on the cuticle, it seems probable that removal should be fairly simple via several different mechanisms, depending upon the preference of the user. No specific experiments studying the potential for buildup of these polymers on hair was found though, so as always, try it yourself, and see if you like it.

Want More?

10 Sun Protection Terms You Need to Know

Handling Diluted and Homemade Products

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[i] Crodasorb UV-HPP, Technical Literature

[ii] Cardinali, S. Protecting Hair from UV Damage, Croda, Inc.

This article was originally published in September 2012 and has been updated for grammar and clarity.

The Truth About Avocado and Wheat Germ Oil

I don’t usually talk much about my hair, but lately it has been dry and tangled! Seriously — it is awful. I think a poor choice in a do-it-yourself color process and my being in-between “holy grail” conditioners are both to blame. Since I hate the feel of a haystack on my head, I have been experimenting with different oils and home treatments, while I ponder which commercial products to purchase for a (hopefully”> more long-term solution.

While perusing the forums here at in hopes of discovering a new conditioner, I have read several discussions about avocado and wheat germ oils and whether or not they contain significant amounts of plant protein. Since some of us with curly hair love and seek out conditioning products that contain proteins, while others avoid them like the plague, it is an important question. Thus, I thought it would be relevant and possibly fun to examine these two plant oils more closely.

Avocado oil and wheat germ oil are derived from their respective sources using various methods; typically solvent extraction, cold press or mechanical extraction, and more rarely, supercritical carbon dioxide extraction. What each of these techniques has in common is that they act to separate the relatively low molecular weight oils (fatty acids”> and oil-soluble vitamins and minerals present in the fruit or seed from the other materials that comprise the whole — fiber, protein, sugars and water.

Although I have seen various products advertising that their wheat germ oil contains “many proteins,” the evidence does not support this assertion. I wanted to get the opinion of an expert, so I consulted Professor Dunford of Oklahoma State University’s Department of Biosystems and Agricultural Engineering. He states that some solid granules or particles may get into the oil during the extraction process, which can lead to the inclusion of some small amount of protein in the oil. However, refined oils go through multiple steps of purification, including additional solvent extraction, filtration, and drying. For this reason, most of these oils used in cosmetics and personal care products should contain no more than trace amounts of protein, if any at all.

Relative concentration of the oil and trace amounts of protein should also be considered. If an oil comprises 1% by weight of a product (or even 5%”> and contains a very small amount of protein, the protein concentration is negligible upon dilution of the oil into the product formula and even more so when diluted by water in application. It is my educated guess that the concentration of protein in a product or even in a direct application of the oil will be substantially less than in a protein-containing conditioner.

So what is in these oils that makes them special?

Wheat germ oil

Wheat germ oil (“triticum vulgare” on most personal-care-product labels”> is a very nutrient-rich plant-derived oil that contains a variety healthful substances. Among these are several different longer-chain fatty acids, long-chain saturated fatty alcohols such as octacosanol, and plentiful amounts of several vitamins and minerals. It is especially valued for its high content of tocopherols (Vitamin E”>, known to provide many health benefits.

Wheat germ does not differ from other triglyceride-derived oils, in that it contains a variety of fatty acids, the exact ratio of which will vary. The major components, in descending order of concentration, are:

  • linoleic acid, an omega-6 essential fatty acid
  • oleic acid
  • palmitic acid
  • linolenic acid, an omega-3 EFA

Several other fatty acids are present in very small quantities. The average molecular length of the major fatty acids in wheat germ oil is larger than that of coconut oil, which may give enhanced emollient benefits to wheat germ oil. The presence of the long-chain fatty alcohols also provides an additional boost to the conditioning and moisturizing properties of wheat germ oil. Based on its chemical profile, it seems like a great product to include in your home hair care routine.

Avocado oil

Avocado oil is comprised mainly of oleic acid, palmitic acid, and linoleic acid. It also has several other fatty acids present. Its main fatty acid components are almost identical to those found in wheat germ oil, but the distribution differs. Avocado oil also contains significant amounts of Vitamins A, E, and D, again with Vitamin E being present in significant amounts. This oil is valued for its light feel and excellent emollient properties.

The magic ingredient in both oils?

Both wheat germ oil and avocado oil contain significant amounts of tocopherol, or Vitamin E. Vitamin E has been found to be especially beneficial as a moisturizing agent for both hair and skin due to its ability to penetration beneath the surface.. Studies have shown that tocopherol acetate (Vitamin E acetate”> is absorbed directly into the hair cortex, where it can moisturize and plump the hair shaft. Deposition/penetration profiles have shown that significant amounts are absorbed, and that the effects are cumulative. Deposition is found to be increased on the surface of damaged hair, which is of significance for curly hair, which is more likely to have a damaged cuticle layer.

Another fascinating attribute of Vitamin E is that it has been found to possess properties that enable it to aid in the prevention and reversal of some forms of hair loss. As a powerful anti-oxidant, vitamin E can also protect the hair from damage caused by free radicals encountered due to exposure to UV radiation (sunlight”>, chemicals and pollutants.

The incorporation of natural, plant-based oils into a home hair care routine is a timeless tradition. It is so much fun to play with them, as there are so many with which to experiment and most of them smell really good! The two oils discussed in this article seem to be exceptional candidates due to the fatty alcohols present in wheat germ oil and the Vitamin E found in both of them. Unless one has a severe allergy to wheat protein in particular, I would also not be concerned about the presence of any trace amounts of protein molecules in the oil. So, once again, it is time to hit the health food store and stock up on some cooking and beauty products!



Skolnik, P. Eaglstein, W.H., Ziboh, V.A. “Human Essential Fatty Acid Deficiency.” Arch Dermatol, 1977; 113 (7″>: 939-941 (ref. 6751″>. — fatty acids and hair loss

Email your questions to Tonya.

This article was originally published May 2009.

The Ingredient with All the Slip, Zero Buildup

hair products with Quaternium-80


Quaternium-80 is a conditioning ingredient found in moisturizing shampoos and conditioners. It is reported to be a great emollient and detangler, but its name causes quite a bit of confusion as to its role and mechanism by which it performs in products. Is it a polyquat or silicone, and is it prone to buildup? Is it water soluble? These are important questions to curlies who want to maintain their high standards of care for their hair. Fortunately, a quick look at the chemical structure of this ingredient and a comparison to other common categories of conditioning agents will provide us with lots of good insight about it. 

What does quaternium mean?

The International Nomenclature for Cosmetic Ingredients (INCI”> system of naming is not always descriptive and specific like the International Union of Pure and Applied Chemistry (IUPAC”> system, so sometimes the names are a bit mystifying. The term quaternium is a hybrid word used as chemical shorthand to describe quaternized ammonium cation compounds.

Quats are molecules or parts of molecules that contain a central nitrogen atom bonded to four different species, which imparts a positive charge to the central nitrogen atom. In cosmetic applications, quaternium refers to certain cationic surfactants that have a fatty acid-derived hydrophobic tail with a hydrophilic quaternized ammonium head.

A few examples of common quaternium compounds used in hair care products are stearalkonium chloride, cetrimonium chloride, cetrimonium bromide, and behentrimonium methosulfate. These molecules are water soluble, very versatile, and are used in oil-in-water systems as conditioning agents as well as emulsifiers for water insoluble ingredients such as silicones.

What do they do?

The cuticle surface of hair possesses a mild overall negative charge, which becomes more pronounced in color-treated, chemically-processed, or otherwise damaged hair. Positively-charged head groups of quaternized ammonium surfactants adsorb onto the surface of the hair as a result of electrostatic attraction to these negatively-charged sites. The molecules are held in place at that site, and the hydrophobic tail of the surfactant molecule drapes itself along the axis of the hair strand, forming a film on the surface of the cuticle. This film provides several benefits, including facilitation of wet and dry combing and detangling, elimination of static electricity and fly-away hair, and improved slip and tactile feel, i.e. silky hair.

Polyquaternium materials are polymers that have been modified to have multiple cationically-charged quaternized ammonium sites along their backbones or hanging pendant from the backbone. These substances adhere extremely well to hair and form a smoothing, protective film, because the many positive sites bond with many negative sites on the cuticle surface. This makes them fabulous conditioners for many people, and they do provide many benefits such as improved color retention and some thermal protection as well. However, some people experience buildup or unwanted accumulation of these materials on the surface of their hair, due to the tenacious nature of the bond formed between the polymer and the cuticle.

Quaternium-80 is a member of a group of specialized quats (sometimes referred to as silquats or silicone quats“> that have a quaternized ammonium head and a silicone tail, rather than a hydrocarbon one. Although quaternium-80 is not a polyquat, it is actually a polymer with a silicone middle, and a positively-charged ammonium ion on each end. The silicone portion does not have multiple cationic sites along its backbone, so it does not pose the same problems as polyquats with regards to removal. Its water soluble nature means that a mild shampoo or conditioner wash should be completely sufficient to remove it from the surface of the hair.

Quaternium-80 is:
  • a cationic surfactant known as a quat
  • a modified silicone
  • water soluble
Quaternium-80 is not:
  • a polyquaternium (polyquat”>

This specialized polymeric surfactant has been found to provide excellent targeted conditioning and anti-static properties in a manner similar to other quats, but with superior detangling and wet combability. Where it really stands out is in the high amount of gloss and shine it provides, as well as the very silky tactile feel reported by users in laboratory trials. The silicone portion of the ingredient is undoubtedly responsible for its unique performance. Since it is water soluble, the enhancing properties of a silicone polymer can be enjoyed without fear of build up.

Products with Quaternium-80

Ouidad Color Preserving Shampoo, Aphogee Curlific Moisture Rich Leave-In, Creme of Nature 7-in-1 Leave-in Treatment, Curls Unleashed Moisturizing Conditioner, DevaCurl No-Comb Detangling Spray, Ouidad Curl Quencher Curl Cream



In closing, the silicone quat ingredient quaternium-80 is a conditioning agent that provides excellent benefits, especially to regions of greater damage on the cuticle. It is very substantive and forms a smooth, protective film over the hair, and provides anti-static effects, ease of combing and detangling, a silky feel, and high gloss. While it does adsorb onto the surface of and adhere to the hair to provide durable conditioning benefits, its water soluble nature and few (only two”> quaternized sites mean that it is relatively easy to remove from the surface of the hair, unlike polyquaternium conditioners.