Dear Tonya: Why is it that some products formulated with “gentle” surfactants and marketed as natural or sulfate-free actually seem to be more drying and damaging to my hair? I thought these products were supposed to be more gentle and kind to my fragile curls.

A: This question pops up frequently, and I have asked it myself when trying out new products without having really scrutinized the ingredients list. (Yes, even the CurlChemist sometimes buys things without much regard for the ingredients list, simply because the products look nice, smell nice, or have good promises on the package”>. Several factors are at play here.

Gentle Shampoo

Concentration of Cleansing Agent

It is possible that some of these sulfate-free shampoos contain very high percentages of surfactant, resulting in a product that is more effective at removing fatty acids and dirt from the scalp and hair. This can be disastrous for hair that is already fragile and that struggles with being too dry already. Unfortunately, it is not possible to determine this information by reading the ingredients list, as the labeling requirement is simply that the ingredients are listed in order of concentration—typically highest to lowest. Thus, the first surfactant on the list could be in the formula at 10%, 20%, or even 30% (or anything in between”>, and it would not be evident to the consumer.

Lack of gentle co-surfactants

Many products formulated with some of the stronger surfactants contain additional detergents called co-surfactants. These are typically materials such as cocamidopropyl betaine, fatty alcohols, and mild cationic surfactants. The mixture of these various surfactants act to diminish both the potential irritancy of the product and the oil stripping capability. The micelles formed in such mixed surfactant systems exhibit different physical and kinetic behaviors than those comprised of a single surfactant. The result is typically a milder formulation. Some of the products advertised as more pure or more gentle actually leave this important step out of their formulation.

Lack of fats/oils/conditioning agents

Good-quality cleansing products include moisturizing agents in their formulation that help to redeposit some oils onto the surface of the hair to prevent excessive drying from the washing process. Again, some of the simpler products that claim to be gentle may be missing this important component of the formulation.

Tonya McKay


Tonya McKay Becker is a curly-haired polymer scientist and cosmetic chemist whose academic and industrial research experience have provided her with expertise in the fundamentals and applications of polymer science and colloid chemistry. She has long had a fascination with the structure-property relationships of the complex solutions used in hair and skin care products, and how they interact with and impact these remarkable biological substrates. Ever curious, Tonya has dedicated herself for more than a decade to honing her expertise on the science of curly hair, how it differs from straight hair, and how product ingredients used on curly hair affect its health and beauty. Her passion for sharing this knowledge with others has led to her current career of educating people from all backgrounds who share an interest in this exciting field.

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