Articles By Tonya McKay

CurlChemist

Woman straightening her hair with a flat iron

Low Heat Styling: Gentle or Damaging?

Heat styling has long been an accessible method to achieve a new hair style, whether it's a carefully curled look or a glossy straight one.

Unfortunately, subjecting hair to the high temperatures of blow drying, curling, or flat ironing can have disastrous effects on its health and beauty. This is especially true for delicate, curly hair with its tendency to be particularly vulnerable to structural damage and breakage.

For this reason, many naturally curly haired people avoid using heat on their hair at all and rely upon air drying, scrunching or pineappling, and strategic placement of clips to impart body and shape to their tresses. However, the occasional yearning for a temporarily smooth, flat hairdo is felt by many, and the allure of the flat iron is ever present.

Low Heat Styling Tools

Many styling tools offer options to operate the equipment at lower temperatures. Recently, one company (CoolWay™, The Low heat Revolution) has been marketing a low heat flat iron styling system as a way to safely achieve straight tresses without all the damage.  Among other things, their appealing claims boast that their system reduces drying time, increases hair strength by 300%, reduces breakage by 75%, and reduces frizz by 50%.

But are lower temperatures truly safer for your hair, and if so, what is the temperature threshold for safe usage?  Answers to that question can be found in a deeper understanding of how thermal damage occurs, the role water plays, and finally the mechanism and efficacy of thermal protection serums in its prevention.

What does heat do to hair?

Breaks hydrogen bonds

Application of heat to the hair breaks hydrogen bonds, and the use of tension or pressure allows hair to be re-shaped so that the new hydrogen bonds form to support the new shape (straight or curled).  These bonds generally remain in place until the hair is washed again or until they slowly revert to their preferred conformation, which means hair straightened via flat ironing can be silky and straight for a few days at a time.

Unfortunately, the temperatures required to achieve this effect can cause permanent structural damage to hair, especially when coupled with the relatively high mechanical forces used to change the shape of the hair. Flat irons are the ultimate players in the heat styling field, with temperatures easily reaching 350°F and even approaching (or surpassing) 400°F.

Structural defects

Hair exposed to the extreme conditions of flat irons has been observed via optical microscopy and scanning electron microscopy and both radial (outward from the shaft) and axial (along the length of the strand) cracking have been observed on hair strands, as well as fusion of cuticle scales.  These structural defects become weaknesses that can result in frizz, tangling, and ultimately breakage.  Loss of curl pattern is also a common effect of repeat exposure to this method of straightening.

Bubble hair

Perhaps even more disconcerting has been the presentation of what has been labeled “bubble hair” in the industry, where hair exposed to the high temperatures of flat iron straightening develops voids and bubbles along its length. Hair is naturally filled with miniscule voids that hold air, which can also absorb and retain water.

When the local temperature of this water exceeds its boiling point, which can happen very easily with exposure to high temperatures in heat styling and blow drying, it can vaporize quickly and boil out of the hair, expanding the voids to form large, vacant bubbles in the structure of the hair. These bubbles give the hair strand an irregular, knobby shape, which is not only unattractive, but also creates stress concentration sites and multiple sources subsequent of breakage.

For this reason, it is extremely important to never flat iron hair that is not absolutely dry. Any residual dampness from washing puts the hair at greater danger for extreme, irreversible damage from rapid boiling of the water molecules. Since hair is never 100% free of water (which would be an undesirable state anyway), this risk is never completely eliminated.

Woman holding heat damaged hair

Minimizing Damage

Lower temperatures

Multiple variables determine the type and extent of damage done by high temperature exposure, including the condition of the hair, the temperature being applied, and the duration of the exposure.  Hair in excellent condition will be more resilient and less likely to incur damage.

Outcomes are also greatly improved when lower temperatures are used and exposure times are minimized. However, evidence has been found that temperatures as low as 125°C (254°F) on a flat iron can induce formation of bubbles in the hair shaft.

The makers of Cool Way claim that the flat iron has a special sensor technology that enables it to automatically detect the moisture levels in the hair and to adjust the temperature for styling accordingly, with the additional promise that the temperature will never exceed 299°F.

This definitely is an advantage for this system over others that rely upon higher temperatures, but it is unclear whether it is sufficient to actually prevent damage to the hair. One of their claims, though, is that hair melts at 320°F, which is definitely untrue and should make the user cautiously skeptical regarding other claims made as well.

Thermal Protection Serums and Sprays

One popular method for reducing thermal damage incurred to hair when using heated styling tools is to apply specially formulated topical treatments designed to act as barriers against high temperatures.  Data has shown that these products can significantly reduce the damage done to hair by flat irons and curling iron and that they also improve water retention in the cortex of the hair.

Examination of the ingredient lists of these serums and sprays reveals that the most common active components of these products are silicones. Silicones provide a variety of benefits as thermal protection materials. Cyclopentasiloxane and cyclomethicone are used to aid in faster drying time, as they are volatile, small molecule silicones. They provide protection to the hair by driving off water more quickly and minimizing the likelihood of water boiling out of the hair shaft.

Higher molecular weight silicones such as phenyl trimethicone, dimethicone, and amine-functional silicones have very low thermal conductivity, which allows them to act as excellent insulators for hair against heat. They spread easily onto the surface of the hair and form films that encapsulate the hair and not only protect against heat very effectively, but also act to seal in moisture. By preventing water molecules from exiting the hair shaft, they effectively prevent formation of voids and bubble defects. While silicones are very good in this capacity, many people prefer to avoid them or use them only minimally.

Thermal protection serums do improve the outcome of using a flat iron, curling iron, or blow dryer set on high temperatures. However, they are usually extremely high in silicones or other non-water soluble polymers, and may cause problems with buildup or lead to limp tresses for some. They definitely could not be removed from the hair purely with a conditioner or mild shampoo.  So it is important to make certain that you cleanse your hair to remove these types of products once you are ready for your hair to revert to its natural state.

Straightening hair with flat iron

Summary

Although it is becoming popular to lower heat tools to change the shape of your hair, it is critical to remember that it really requires relatively low temperatures to cause irreversible damage to your hair structure.

The Coolway™ Low Heat styling system's ability to adjust temperatures automatically based upon the condition of your hair is an interesting technology, but in comparison to other very high temperature flat ironing tools the improvement is only marginal.

The temperatures used in devices with adjustable heat settings are substantially lower than the 400° often seen in the most powerful flat irons, but they are still sufficiently high to cause structural damage to the hair.

There is an important relationship between the transmission of thermal energy and the size of the object receiving the energy. Hair strands are very small, as are the proteins, lipids, and water molecules which comprise them, and energy is transmitted very rapidly into those structures.

Remember that water boils at 212°F, and individual molecules can reach that temperature very quickly and easily, even with temperatures of only 200°F on the styling tool. Keratin proteins are denatured at even lower temperatures.

The longer a tool remains in contact with the hair, the more thermal energy it conveys to each hair strand which can lead to really catastrophic damage, such as bubbles, voids, distortions of the geometry of the hair, permanent disruption of the curl pattern, fusing of cuticle scales, and ultimately, breakage.  For this reason, gliding a flat iron quickly across the surface of the hair, in one swift, smooth movement is critical.  Damage is cumulative, so frequent use of high heat styling methods increases the chances of noticeable degradation of the health of the hair.

Thermal protection sprays and serums utilize silicones and other polymers, which have been found to provide some degree of protection when used in heat styling applications.  However, these products are prone to accumulation on the surface of the hair, which can cause dryness, frizz, and limp tresses.

It seems if one wanted to occasionally sport a straight hairdo, then using a lower heat flat iron is indeed a safer choice by which to achieve that end.  However, subjecting one's hair to these conditions on a daily or even weekly basis will inevitably cause structural damage to the hair, which is just not reversible.  We take too much care with the condition of our hair to risk it too often in pursuit of those flat, glossy styles.
Embrace your curls!


MORE: Low Heat Styling Tips for Curly Hair

References

  1. Zhou Y, et al., The effect of various cosmetic pretreatments on protecting hair from thermal damage by hot flat ironing, J Cosmet Sci. 2011 Mar-Apr;62(2):265-82.
  2. Christian PWinsey NWhatmough MCornwell PA, The effects of water on heat-styling damage, J Cosmet Sci. 2011 Jan-Feb;62(1):15-27.

A “sweet” new group of ingredients being used in the green formulating industry is the Sucragel line of products developed by Alfa Chemicals in the UK. Rather than being a single ingredient, these materials are provided as  mixtures of natural oils, glycerin, and esters of the sugar molecule, sucrose.

Sucragels can be easily incorporated into a variety of hair and skin products where they provide thickening to the product, emulsion stabilization, mild cleansing and for leave on products, impart hydration to the skin and hair through the attraction and binding of water molecules to the humectant sugar molecules.

Sucragel enjoys the prestigious European Ecocert label, which means it is internationally accepted as a viable option for natural formulations and can be used in products for companies whose policies regarding the quality and safety of their ingredients are rigorous.

Sucragel is PEG-free, biodegradable, preservative-free, entirely vegetable derived, is available in a 94% organic option, and is amenable to cold process technology, which uses less energy and is considered a more sustainable business practice for manufacture of products. These mixtures add benefit to formulations for both skin and hair, and are found in a variety of products so far, including several Burt's Bees gentle shampoos.


MORE: Top 10 Ingredients of Natural Hair Products


What are Sucragels?

Sucrose laurate is then mixed with glycerin, water (aqua), and an oil phase consisting of either caprylic/capric triglycerides or sweet almond oil. The final solution is Sucragel, which can be readily mixed with a variety of nonpolar oils, including botanical oils, silicones, mineral oils, and esters, to produce a stable, clear, oily gel. Sucragels are a mixture designed to capitalize upon the nonionic surfactant properties of sugar esters.  These are obtained by an esterification reaction between sucrose and a fatty acid, typically the coconut fatty acid (lauric) to produce sucrose laurate.

Where will I find them?

The resultant gels can be added to aqueous mixtures, where they emulsify spontaneously, which is useful for making lotions, face creams, cleansers, or lightweight conditioners. Additionally, the oily gels can be used to make excellent deep conditioning treatments or as light topical humectants if applied sparingly. The ease with which these materials can be used in formulations makes them suitable materials for home dabbling in cosmetics chemistry.

Sucragels can be used in

  • Shampoos
  • Lightweight leave-in conditioners
  • Skin creams
  • Deep conditioning treatments
  • Light topical humectants

Sucragels also have application as co-surfactants in low-foaming, mild shampoos.  Burt’s Bees makes use of Sucragel in a variety of their natural shampoos for adults and children.  They are also found in A'kin shampoo, Organic Surge shampoo, The Body Shop rainforest shampoo, Madara shampoo, and The Organic Pharmacy, to name a few.  Due to their amphiphilic, nonionic structure, they provide very mild cleansing and are considered moisturizing.  They are used in products targeting safety and health as replacements for PEG-modified surfactants, which are coming under scrutiny for potential health complications.

Sucragel can also be used in lightweight leave-in conditioning products, especially if the primary conditioning agent is a silicone or botanical oil.  In these they impart hydration and moisturization both from the almond oil and the sugar ester.

Sucragel seems to be primarily suited for hydration and emulsification purposes, and is thus appropriate for use in shampoos, leave-in conditioners, and skin creams. It is not readily apparent from the product literature whether it is compatible with some of the typical styling polymers, such as acrylates or pyrrolidones.  It is sensitive to electrolytes in the solution, which indicates that the cationic conditioning and styling polymers would definitely not work well with these materials.  It would be interesting to see if they added anything beneficial to a flax seed gel or something similar.

What to look for on labels

Several different Sucragel mixtures are available for formulators, so they have multiple INCI designations for labels.

  1. Sucragel CF: Glycerin & Caprylic/Capric Triglycerides & Aqua & Sucrose Laurate
  2. Sucragel AOF: Prunus Amygdalus Dulcis (Sweet Almond) Oil & Glycerin & Aqua & Sucrose Laurate
  3. Sucragel AOF BIO (94% Organic): Glycerin & Prunis Amygdalus Dulcis (Sweet Almond) Oil & Sucrose Laurate & Citrus Aurantium Dulcis (Orange) Fruit Water

MORE: Decipher Hair Product Ingredients and Read Your Labels! 


Summary

Sucragels are a mixture of sugar esters and oils that enable formulators to create viscous, oily gels and stable emulsions for a variety of hair and skin care products.  They provide mild cleansing, emulsion stabilization, environmentally friendly manufacturing, and are biodegradable, to name some of their desirable traits.  Some research studies have shown that in certain mixtures, these materials form some very interesting structures (bicontinuous phases) that may provide more sophisticated avenues for application in the future.  An additional perk is that they are also obtainable from a variety of sources so that it is possible to play with them at home to see how they work for you.
While these sugar ester based mixtures may not be tasty (but they are edible), they do seem to be a fantastic resource for the cosmetic market. The sugar esters themselves are water soluble, but the plant oils require a mild cleanser to be removed thoroughly from the hair surface.  Due to their highly hydrophilic structures, the humectant properties from both the sucrose ester and the glycerin may produce a tacky feel to the hair and even lead to frizz, especially in certain environmental conditions, so be aware of this if you choose to use leave-in products containing these.  Overall, the Sucragel mixture is very gentle material with much potential as formulators both at home and in labs strive to develop products that embrace the green philosophy.


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.

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

Woman scratches itchy scalp

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

jars full of ingredients

Common Allergens

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  1. 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.
  2. 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.
  3. 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.
  4. 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

Conclusion

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. 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


 


Mongongo oil

Mongongo oil has been valued for centuries in Africa and is now gaining popularity in the rest of the world as we become educated about its beneficial qualities. Not only is the fruit extremely nutritious, but the oil has many useful properties as an emollient for both hair and skin. What makes mongongo different from other botanical oils and how does this affect its properties?

Origin

Mongongo oil is obtained by cold-pressing the nuts that come from the Mongongo or Manketti tree (Schinziophyton rautanenii). The Manketti tree is found from coast to coast in Southern Africa. It thrives in the seasonal dry lands where it weathers a broad range of temperatures from sub-freezing to scorching desert heat. It is found both sporadically scattered and also in large groves throughout northern Namibia, southern Angola, Zambia, Botswana, Zimbabwe, Mozambique and Malawi. The egg-shaped, reddish brown fruit is prized by both the people and the elephants indigenous to the region. The nuts are often gathered from elephant dung, a practice that is less labor intensive than harvesting the fruit and extracting the nut from the center.

Composition of Mongongo Oil

The nut is very high in fat (>57%) and contains a plethora of other valuable nutrients, such as calcium, magnesium, iron, copper, zinc and thiamine. Each seed contains approximately 560 mg of vitamin E (tocopherol). The antioxidant properties of this vitamin lend a high degree of thermal and oxidative stability to the oil, which greatly delays onset of rancidity of the oil, even in the intense South African heat. The oil has been greatly prized, not only for its nutritive benefits, but also as a skin and hair emollient and skin protectant.

The composition of the oil in mongongo fruit is fairly different from many other plant oils used as topical hair treatments or conditioning ingredients. It is comprised of between 40-50% polyunsaturated fatty acids, as compared to shea and coconut oil, which are comprised largely of saturated fatty acids and mango, olive, avocado, jojoba and almond oils, which are comprised mainly of monounsaturated oils.

Fatty Acid Content of Mongongo Oil:

  • 45-55% polyunsaturated fatty acids: linoleic acid, alpha-eleostearic acid
  • 17% saturated fatty acids: palmitic acid, stearic acid
  • 18% monounsaturated fatty acid: oleic acid

Unsaturated molecules have at least one carbon-carbon double bond in their structure. Double bonds are connected at a different angle than single ones and this produces a kink in the molecular geometry. This type of structure inhibits crystallization by impeding packing of adjacent molecules. For this reason, oils with high concentrations of polyunsaturated and monounsaturated fatty acids are typically either liquids at room temperature or melt readily upon contact with skin.

Stearic acid, a saturated hydrocarbon molecule with 18 carbons (relatively long-chain fatty acid) has a melting point of 69.6°C (157.28°F). Oleic acid is a monounsaturated hydrocarbon with a melting point of 10.5°C (50.9°F). Polyunsaturated acids, such as linoleic and linolenic, have multiple kinks in their chains and are liquid at very low temperatures (melt point = -5°C (23°F) for linoleic acid).

MORE: 6 New Hair Oils for Your Curls

Structures and Chemical makeup of mongongo oil

Properties of the different types of fatty acids

The protective outer cuticle layer of hair is not a solid surface, but is porous in order to allow transport of oils and water back and forth through the hair and into the cortex. The lipid-rich cell membrane complex layer just beneath the cuticle scales acts as a diffusion port, enabling fatty acids and moisture to travel into the interior of the hair strand.

Molecular size and shape determine the probability of a fatty acid to travel through the cuticle layer into the cortex of the hair. Saturated fatty acids such as stearic acid, lauric acid and palmitic acid diffuse easily through the pores of the cuticle layer and penetrate the cortex, where they provide flexibility and suppleness to hair strands. Spectroscopic studies demonstrate that despite their kinked structure due to the single double bond, monounsaturated fatty acids are also able to readily penetrate the interior of the hair via this route.

However, the more unwieldy structure of polyunsaturated fatty acids prohibits them from penetrating into the interior of the hair strand and they remain adsorbed onto the surface of the hair. Oils such as mongongo oil that are high in polyunsaturated fatty acids, form a protective and emollient film on the surface of the hair, where they act as a barrier preventing moisture from escaping the interior of the hair. These fatty acids can add gloss to hair and improve comb-ability by smoothing the surface of the hair. Due to the presence of the acid groups in their structure, these ingredients can also have a mild humectant effect.

Oils such as mongongo oil that are high in polyunsaturated fatty acids, form a protective and emollient film on the surface of the hair, where they act as a barrier preventing moisture from escaping the interior of the hair. These fatty acids can add gloss to hair and improve comb-ability by smoothing the surface of the hair.

The linoleic acid in mongongo oil is known for being emollient to the hair, and stearic acid, palmitic acid and oleic acid are good at penetrating to the cortex to supply elasticity and improved mechanical properties. Perhaps the most interesting properties of mongongo oil can be attributed to the presence of α-eleostearic acid, a conjugated trienoic fatty acid. This molecule has three double bonds in the middle of its structure that are conjugated, meaning they alternate (double bond-single bond-double bond-single bond…). These types of structures have unique chemical properties due to this conjugation, as they can delocalize certain of their electrons in response to various stimuli in a process known as resonance stabilization.

There are three reasons that this very specific feature of the organic structure of α-eleostearic acid is interesting to us in hair care applications. The first is that the conjugated diene structure enables this fatty acid to act as a mild sun protective agent via UV-absorption and subsequent resonance stabilization. The second reason is that the molecule is capable of undergoing a UV-initiated photopolymerization reaction, whereby the fatty acids molecules link together into a three-dimensional crosslinked network, forming a flexible film on the surface of the hair. This provides physical protection to the hair and also may impart style hold or curl retention. Thirdly, this polymerization mechanism (called curing) substantially reduces drying time for hair. Even once polymerized, the carboxylic acid groups on the molecule should be sufficient enough “hydrophilic handles” to permit removability in water, especially if conditioner and/or mild shampoo are used.

Since it is fun to experiment with our hair, it seems worthwhile to at least sample some of these new products containing this ingredient. Look for products that contain other quality ingredients and that feature mongongo oil sufficiently high up the ingredient list. Beware products that are comprised primarily of other oils and only include this as a trace ingredient as they may prove to not be a sound investment. Let us know your thoughts when you do try some of the new mongongo oil products.

MOREOrchid Oil: A Breakthrough Hair Care Ingredient

References:

  1. Dyer, J.M., et al, http://naldc.nal.usda.gov/download/22993/PDF, Differential Extraction of Eleostearic Acid-Rich Lipid–Protein Complexes in Tung Seeds, JAOCS, Vol. 75, no. 11 (1998)
  2. Yang et al. BMC Plant Biology 2010, 10:250, http://www.biomedcentral.com/1471-2229/10/250

 


Lady laying down with curly red hair spread out over the desert floor

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?

Lady wearing a hat over her curly blonde hair and smiling up at the sun

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.


[i] Crodasorb UV-HPP, Technical Literature

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


Silicones have many unique properties that make them a preferred ingredient for hair care product formulators. They form a film on the surface of hair strands which allows them to effectively act as a lubricant between adjacent hair strands and reduce the forces required for detangling hair. Due to their high refractive index, they also impart a high degree of gloss and shine to hair when used in conditioners and styling products. Silicones also provide protection from the thermal damage often sustained during hair drying and heat styling. Certain silicones, especially amine-functionalized ones, have also been shown to increase color retention of artificially dyed hair.

However, despite their numerous benefits, curlies are frequently admonished to minimize use of silicones or to avoid them entirely.

So what's the problem?

Sadly, there can be too much of a good thing. Years ago, it was fashionable for stylists to douse curly hair in heavy silicone oils in order to get control of frizz and to add a much-coveted shine to curls. Unfortunately, these products had a tendency to backfire over time. With repeated use, the serums accumulated on the surface of the hair, keeping water from entering the cortex and causing it to become dehydrated, weighing down hair, and completely disrupting natural curl pattern. The buildup could be very difficult to remove, requiring repeat applications of harsh shampoos. The result was dry, frizzy hair that resisted attempts to restore its natural beauty.

Similar results can occur when conditioners with high amounts of non-water soluble dimethicone are used. Buildup issues are especially problematic when non-traditional methods of cleansing are employed, such as conditioner cleansing, baking soda scrubs, or vinegar rinses. For this reason, it has become a popular recommendation for curly-haired people to avoid products containing silicones. This has the unfortunate consequence of depriving many curlies of some of the beneficial properties of silicones in hair care products.

Is There a Solution?

Happily, polymer chemists have spent time developing and optimizing water soluble silicone-based polymers for various reasons. These materials impart many of the desirable properties of ordinary silicone polymers, but they are more easily removed from the hair via rinsing, conditioner washing, or cleaning with mild shampoos, and do not require the use of harsh sulfate-based surfactants. They can also enhance moisturizing properties or add humectant qualities. These silicones provide more options to curly ladies and gentlemen.

Read More: Coily Manifesto: Silicone Hair Products Work For Me

What makes a silicone-based polymer water soluble?

Simple silicone polymers, such as dimethicone (polydimethylsiloxane) are comprised of a linear inorganic backbone of silicone and oxygen, with organic (carbon-based) pendant groups. These materials are extremely hydrophobic oils. However, several different types of chemical reactions can be utilized to add hydrophilic character to the polymers. These new polymers are amphiphilic, containing both hydrophobic and hydrophilic portions, and are classified as silicone surfactants.

Perhaps the most straightforward and popular method for rendering a silicone molecule water soluble is by adding multiple units of ethylene glycol (-OCH2CH2O-) to sites along the polymer chain. The oxygen atoms in these segments add polarity to the silicone and are readily available for association with water molecules. This process is called ethoxylation or polyethylene glycol (PEG)-modification.

PEG-modification can be done on sites that dangle from the silicone backbone, which results in a polymer shaped like a comb with hydrophilic tendrils. PEG can also be added to the terminal ends of the silicone polymer, making a straight chain surfactant type copolymer, with a hydrophilic block-hydrophobic block-hydrophilic block structure. Star-like molecules can be created by PEG-substitution occurring both at the ends of the polymer and on the pendant groups. Each type of polymer has slightly different properties.

Happily, polymer chemists have for various reasons spent time developing and optimizing water soluble silicone-based polymers...These silicones provide more options to curly ladies and gentlemen.

On product labels, these polymers were formerly denoted by the name dimethicone copolyol. The preferred nomenclature for the comb-shaped polymers now is PEG-X dimethicone, with X being the number of repeat units of ethylene glycol. The block copolymers are designated Bis-PEG-X dimethicone, and the star-shaped polymers are designated Bis-PEG-X/PEG-X dimethicone. The higher the number “x” is, the greater the water solubility. Below a threshold of approximately PEG-6, the polymer is only sparingly soluble, and when the degree of ethoxylation equals or exceeds 8, the material can be considered to be highly water soluble.

Similar modification of a different silicone results in the novel polymer Bis-PEG-18 methyl ether dimethyl silane, which is completely water soluble and highly moisturizing to skin and hair. Another interesting water soluble silicone polymer is one modified with side chain copolymers of poly glucosides (sugars), PEG-8-PG-coco glucoside dimethicone. This material is completely water soluble, has high substantivity to hair and skin, is very moisturizing, and also has sufficient surfactant qualities that it can be used as a foaming agent and mild cleanser in gentle shampoos. Silicone phosphate esters (INCI name: Dimethicone PEG-X phosphate) are another category of water soluble silicone surfactants that provide excellent moisturizing properties and act as foam boosters.

Read More: What’s the Scoop on Silicones?

What should I look for on labels?

Ultimately, it is most important to be your own scientist and try various products on your own hair in order to determine what gives the results that you like the most. What works for one person may not work for another, for many reasons.

Read More: CurlChemist: What Makes a Cleansing Ingredient More Harsh or More Gentle?

If you are interested in trying some of the benefits of silicone-based products, but find it important to stick to those that are most easily removed via no-shampoo and mild-shampoo techniques, you will need to know what to look for on labels. The following silicones should be compatible with that type of hair care routine, and should provide many of the desirable effects of silicones, such as the addition of shine, moisturizing effects, thermal protection, and color retention, without any accompanying worries about buildup and frizz..

  • PEG-8 (or higher) Dimethicone
  • Bis-PEG-8 (or higher) Dimethicone
  • Bis-PEG-8/PEG-8 Dimethicone
  • Bis-PEG-18 methyl ether dimethyl silane
  • PEG-8-PG-coco glucoside dimethicone
  • Dimethicone PEG-X phosphate
  • Dimethcione copolyol (this is an older and less descriptive designation, but may still be found on some labels)
So curlies, are you willing to let your hair make friends with these water-soluble  silicones? 

young lady with curly hair sips from an orange half with a straw

There is no mistaking the current trend in the cosmetics industry to incorporate vitamins and plant derivatives into formulations in order to advertise products as healthy, natural, green, sustainable or possessing anti-aging properties. One popular claim suggests using vitamin C for hair growth. As an essential nutrient for health, vitamin C takes part in many cellular processes and must be ingested by humans in significant quantities as we do not manufacture it internally as some other species do. Centuries ago, it was common knowledge that deficiency in this nutrient (later identified as vitamin C) among sailors on long voyages and the malnourished poor caused a horrible condition known as scurvy. The condition was determined to be easily preventable with the consumption of relatively small amounts of fruit or vegetables that had abundant levels of vitamin C. It is critically important for optimal function of the immune system and for tissue growth regeneration. Clearly, vitamin C is well-established as a necessary substance for internal consumption. But, does it really have any benefits when used externally in skin and hair?

Vitamin C in Beauty Products

Perhaps not surprisingly, the answer is sometimes yes, sometimes no. 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. 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.

Properties and Benefits

Vitamin C is a small molecule organic acid, with key structural features in common with other mild acids, such as acetic acid (vinegar) and citric acid. For this reason, 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 resistant to tangling and breakage. 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 anti-oxidant, 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. 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 build up 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.

Vitamin C for Hair Growth

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.”

Final Thoughts

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!


Zwitterionic Surfractants

In recent months, we have taken an in-depth look at the structure and properties of cationic and nonionic surfactants. Another interesting category of surfactants used in both hair and skin care are the zwitterionic ones, those that naturally have two charges on the molecule, both positive and negative. These are attractive to the formulator due to their tendency to boost effects of other surfactants in the solution, as well as an ability to ameliorate undesirable properties of some surfactants, such as skin irritation and a tendency to strip the hair and skin of too much moisture. One familiar surfactant of this type is cocamidopropyl betaine, which is appreciated by many curly-haired consumers for its gentle, yet effective, cleansing capabilities.

What are they?

Zwitterionic surfactants (also: amphoteric surfactants) are characterized by having two distinct and opposite charges on the molecule at either adjacent or non-adjacent sites. The presence of both a positive and negative charge renders the molecule overall neutrally-charged at neutral pH. Some types of zwitterions are susceptible to pH changes in a solution and may become completely cationic or anionic in acidic or basic environments. The positively-charged site is typically a quaternized ammonium ion, but can also be a phosphonium ion, while the negatively-charged site can be one of a variety of anionic groups, such as sulfate, carboxylate, or sulfonate. There are several common categories of zwitterions used in hair care formulations, such as the betaines and amphoacetates.

In general, amphoteric surfactants have been found to be compatible with other surfactants and polymers, including silicones. The formation of self-assembling complexes between amphoteric surfactants and polymers or anionic surfactants has been observed and found to impart interesting properties to solutions containing these molecules. Amphoteric surfactants reduce static in hair by decreasing its surface charge density. Since the interactions between hair and zwitterionic surfactants are primarily physical rather than ionic, they are easily rinsed and removed from the surface of the hair. They have been found to minimize skin and eye irritation common to other surfactants, especially sulfates. They also can boost the foaming performance of anionic surfactant systems via a variety of mechanisms, by either increasing the speed at which foam is formed (flashing), improving the density and luxurious feel of the foam, or by increasing the foam stability (longevity).

Types of amphoteric surfactants

The betaine family of zwitterions possesses the positive-negative head group structure of trimethyl glycine (betaine), an amino acid derived from sugar beets. The hydrophobic tail group can be a straight chain alkyl group (such as in coco betaine), or can contain an amido group, such as cocamidopropyl betaine. Other betaines include lauramidopropyl betaine, oleamidopropyl betaine, ricinoleamidopropyl betaine, cetyl betaine and dimer dilinoleamidopropyl betaine. Additional variants are sulfobetaines, hydroxysulfobetaines and sultaines. Betaines are more resistant to thickening via addition of salts than their anionic cousins. For this reason, in order to achieve a pleasingly thick product, addition of viscosity-boosting polymeric additives may be necessary, which can increase the cost and complexity of the formula.

Cocamidopropyl betaine is particularly valued for being an excellent cosurfactant for sodium lauryl sulfate, but it is also a gentle cleanser in its own right. Studies have found that it removes silicones from hair very effectively, without drying out the hair. It has also been shown to improve the solubility of sodium cocoyl isethionate, an extremely gentle, creamy and emollient surfactant. The combination of these two has the potential to create an extremely gentle and moisturizing shampoo.

Betaines are more resistant to thickening via addition of salts than their anionic cousins. For this reason, in order to achieve a pleasingly thick product, addition of viscosity-boosting polymeric additives may be necessary, which can increase the cost and complexity of the formula.

The specific betaine selected can have a significant impact upon the viscosity, foaming behavior and detergency of the final product. In order to choose the best betaine for her purpose, the formulator must be familiar with the properties of each of her options and how each interacts with the other ingredients in her formula. She will generally have a goal in mind regarding the physical properties, cleansing strength and cost of her formula and all of those will factor into the decision. Fortunately, for consumers, the primary concern is how the product feels on the hair and how the hair behaves afterward and the differences should not be tremendous between the various betaines. Currently, cocamidopropyl betaine is the one most often seen on labels and in the proper formulation, and is quite gentle to hair and skin.

Other families of zwitterions are also used in formulations. They are becoming more common as their interesting properties are explored and as companies continue working to develop non-sulfate-based cleansing platforms. Some familiar ones might be the imidazoline derivatives alkylamphoacetates such as disodium lauramphoacetate, as well as alkylamphopropionates. These materials share many of the beneficial and gentle properties of the betaine family.

Overall, zwitterions are an interesting class of surfactants with the potential for more growth in application, especially for curly hair, which needs a more gentle approach to cleansing.

Consumer power

In recent years, there has been a growing demand for sulfate-free and gentler shampoos and cleansing products, especially in the curly-haired population, as we have learned the damage that can be done by harsh surfactants. As formulators continue to respond to the push from consumers for alternatives to sulfate-based cleansing systems, we can expect to see a growing number of products relying upon the milder cleansing properties of zwitterionic surfactants. They are less likely to strip curly hair of its much-needed moisture and can impart a silky feel to hair when used with other ingredients. A patent search reveals that scientists are working to develop more polymer-zwitterion systems, which should also eventually benefit the end product user by providing performance-enhancing properties. In this demand-driven market, the power consumers have to drive the research and development of new products is quite remarkable and should not be underestimated.

Communities such as naturallycurly.com have a voice! So what do you think?

 


PanthenolPantothenic acid, Vitamin B5

Panthenol is a popular ingredient for both skin and hair care products. Hair care products that use this ingredient are said to have enhanced moisturization effects and add thickness or body to the hair. Proctor and Gamble has built their entire Pantene Pro-V line of products to capitalize on the properties of this ingredient. There seems to be a bit of confusion, however, about the role of panthenol in a formulation and whether or not it is beneficial or possibly even harmful for curly hair. A closer look at the chemistry of panthenol should provide clarification about this ingredient.

The Basic Chemistry

Panthenol is a derivative of vitamin B5 (pantothenic acid) and is known as a provitamin. Panthenol is what is called a chiral molecule, or one that has a molecular structure that gives it a "handedness," either right-handed (dextrorotatory) or left-handed (levorotatory). These two mirror-image enantiomers are not superimposable on one another, in the same manner in which your two hands are mirror images of one another rather than exact duplicates. Oftentimes, the two versions of a molecule have differing chemical or biological properties. For cosmetic purposes, panthenol is supplied either as a racemic mixture (50/50) of both types of enantiomers or as the purified "D" version. This is most relevant in skin care applications, as the D-version of panthenol is the biologically active version.

The Properties

The multiple hydroxyl (-OH) groups on the panthenol molecule impart most of the physical properties to it, most particularly its high solubility in water and other solvents. Panthenol is a highly effective humectant, a class of ingredients used in skin and hair care products to promote moisture-retention. It has a highly hydrophilic and hygroscopic chemical structure which attracts water from the atmosphere and binds it to various sites along the molecule. Humectants typically possess multiple alcohol (hydroxyl) or similarly hydrophilic sites (such as ethers or ammonium groups), which are available for hydrogen bonding with water molecules. Hydrogen bonding between humectants and water aids in moisture-retention by minimizing water loss due to evaporation.

Panthenol is not only a humectant, but is also a useful moisturizer and emollient. It spreads evenly on the surface of hair strands, forming a smooth film on the surface of the cuticle. This film gives enhanced coherence to the reflection of light from the surface of the hair, which imparts significant gloss and shine. The smooth film also provides excellent slip between adjacent strands of hair and detangling properties. Panthenol is capable of penetrating the cuticle and entering the hair shaft as well, where it aids in moisture retention and provides volume.

It is important to note that sometimes penetration of the shaft by ingredients can create a rough cuticle surface and lead to frizz, due to swelling of the hair shaft. This may not occur for everyone and is dependent upon several factors, including porosity of the hair and the amount of the ingredient used in the product. It is a potential undesirable effect, so keep this in the back of your mind when using a product containing the ingredient.

Although there is a persistent rumor that panthenol creates waxy buildup on hair, there is no evidence to support such an assertion. Panthenol is not at all similar in structure to waxy materials. It is also extremely water soluble, alcohol soluble, mildly soluble in glycerin and is fairly easily capable of being mixed into most oils. Additionally, panthenol has no component to its chemical structure that would cause it to bind tightly to the surface of a hair strand. For these reasons, it should be easily removed from hair by rinsing, washing with mild shampoo and even conditioner cleansing. If one is experiencing problems with build up and unpleasant hair texture when using a product containing panthenol, the issue is more likely due to other ingredients in the formulation.

Panthenol is readily absorbed by skin, and as the precursor of vitamin B5, it directly impacts metabolic processes in epidermal cells. It has been found to have many beneficial properties for epithelial tissue, including increased hydration and improved elasticity and is believed to promote cell regeneration. When used in shampoos and conditioners, panthenol conceivably provides added benefit by improving scalp health and potentially improving hair growth.

Final Thoughts

Panthenol is a naturally-occurring material that adds several beneficial properties to hair care formulations. It is a humectant, emollient, glossifier, detangler and moisturizing agent. It is highly water soluble and is also easily removable with mild plant-derived oils or via conditioner cleansing. When selecting humectant-containing products, one must keep in mind the climate in which they live, how that impacts hair and how they might expect a humectant to contribute to the overall performance of their own hair within the constraints of that climate. Also, depending upon the porosity of your hair and the type of product being used, you may experience a roughened hair texture or some frizz due to penetration of the hair shaft. If this should happen, it might be best to discontinue use or to decrease use of the product. Finally, experimentation is the best way to find out what works well on your own hair.

 



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