Hair loss is generally considered a genetic and hormonal case where we lose our hair because of our genetic makeup or metabolic changes in our body. Testosterone and its metabolites are known for their role in hair loss. Beside this, our lifestyle, nutrition as well as environmental changes greatly influence overall hair health. The food we eat, smoking and exposure to pollution has been reported to have an impact on our hair conditions. In the same way, cosmetics we use for our everyday grooming and beautifying also affect the hair quality.
Today, almost everyone among us shampoo hair and we use hair conditioners to detangle hair and style for an attractive look. Chemical treatments such as bleaching, oxidative dyeing, perms and straightening are also popular and these products also cause hair damage. For example, chemical bleaching is known to cause significant hair damage leaving the hair fragile, brittle and porous. Cases have been reported with the complaints of hair loss for the patients with a history of repeated applications of cosmetics. Today, we analyze one key and well-known ingredient, sodium lauryl sulfate (SLS) for its role in inducing hair loss.
Sodium Lauryl Sulfate - Function in Personal Care Formulations
Sodium lauryl sulfate is an anionic surfactant added into our shampoos, other cleansing products and even some emulsion creams and lotions. One of the most abundantly used chemical ingredient used in the personal care industry. It is a made synthetically while its main backbone raw material is lauryl alcohol obtained from palm oil. Its main function is to clean our hair (or other surfaces) by removing small oily droplets and dust particulates that get deposited on our hair shaft. Besides this, it is a high foaming chemical which generates a good volume of leather during shampooing and other usages.
Looking at the chemical structure of SLS molecule, it has two distinct features in its molecule
- Long carbon chain usually having 12 carbon members
- Sulfate anion attached at the end of this carbon
It a characteristic feature that surfactants have both hydrophobic (long fatty acid chain) and hydrophilic groups (Sulfate) attached in the same molecules. This shapes up their unique property of dissolving oil into the water. SLS, when added into water, arranges itself such a way that it forms special structures (Micelles) responsible for their cleaning action.
Because of its unique structure, high foaming and cost-effectiveness, it is a preferred choice of formulators for shampoos, facial & body cleansers. It is also added into toothpaste and other household detergents.
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How SLS can cause hair loss?
SLS has been in use for years and the dermatological studies have revealed some insights about this famous ingredient and its impact on our skin. SLS is known to be the most irritant surfactant used in personal care formulations. Various derma studies have reported SLS causing significant skin disorders, erythema and even rashes on repeated exposure to SLS containing personal care products. SLS also strips the natural oil from our scalp and hair leaving them dry and rough.
Our Scalp is a sensitive and delicate surface containing numerous minute blood vessels and capillaries. It also has an extensive network of nerves being part of our nervous system. Mother Nature has designed a unique system to protect this part of the body covering it by hairs. Application of chemicals such as SLS causes irritation, skin redness and in severe cases red patches of rashes. Severe cases of contact dermatitis have been reported using SLS containing products. This causes abnormal blood flow to this area causing a series of other problems.
One disorder is a potential mal-functioning of the hair follicle. In that case, the whole biochemical reactions supposed to happen inside hair follicle are disturbed leading to thinning of the existing hair shaft and finally, hair fall off.
The hair follicle is responsible for the growth of hair after the fall of old hairs. However, with blood supply disturbed and all biochemistry under stress, new hair does not originate and grow at all. This whole biochemical disturbance may eventually lead to closure or death of hair follicle where it would not function normally anymore. This causes permanent baldness and requires specialized treatments to restore the population of follicles at the scalp surface.
What is the alternate strategy?
We need to avoid using SLS altogether. Over the last two decades, consumer awareness has been raised against these irritant chemicals used in products of personal hygiene. Scientific studies have made things easy for us to explain to the general public about the potential danger of using these products. This has pushed the cosmetics industry and formulator to search out alternate ingredients which are mild to the skin and still offer the same level of detergency and cleansing. The good news is, work has paid off. Today we have naturally sourced, green, ecofriendly alternates proven to be mild and they perform equally well. As a result of this, we have now, a whole new class of Sulfate-
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Free products in the market.
Some of the examples of SLS alternates are, Alkyl polyglycoside, a whole new family of sugar-based non-ionic surfactants. In this family, we have coco-glucoside, decyl glucoside and lauryl glucoside commonly used now in shampoos and other personal care cleansing formulations.
The key is to look at ingredient listing when you buying your shampoo or cleanser. Let's avoid SLS and other sulfate surfactants (e.g. Sodium Laureth Sulfate, Ammonium lauryl or Laureth sulfate). This preserves the natural biology of your scalp and quality of hair fibre.
Conclusion & Summary
SLS is an anionic surfactant commonly used in shampoos. It is one chemical used in personal care formulation with the highest irritation potential. It dries out our scalp and hair leaving them brittle and without any shine. Biochemical changes at scalp cause irreparable damage to hair follicle leading to hair loss. We need to avoid SLS containing formulations and look for more green and skin-friendly alternates.
Bibliography & Further reading:
- Zviak, C., The Science of Hair Care. Taylor & Francis: 2005.
- Mottram, F. J., Hair shampoos. In Poucher’s Perfumes, Cosmetics and Soaps, Butler, H., Ed. Springer Netherlands: 1993; pp 170-194.
- Trüeb, R. M., Shampoos: Ingredients, efficacy and adverse effects. JDDG: Journal der Deutschen Dermatologischen Gesellschaft 2007, 5 (5), 356-365.
- Marsh, J. M.; Gray, J.; Tosti, A., Healthy Hair. Springer International Publishing: 2015.
- Tur, E., Environmental Factors in Skin Diseases. Karger: 2007