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.
Shampooing with sulfates and soaps: In previous articles, we have discussed that 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). The CMC acts as cushion and 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.
At normal formulation levels (15-20%), harsh surfactants in shampoos, such as SLS, SLES, ALS, and ALES, are capable of dissolving the lipid layer in the CMC and removing the 18-MEA from the surface of the cuticle. This creates irreparable gaps in the cuticle layer, increasing porosity of the hair. Also, by dissolving the protective fatty acid layer from the surface of the cuticle, the hair is rendered more hydrophilic (water-loving), which is a very dangerous state for hair as it becomes more susceptible to frizz, tangling, and damage to the cuticle scales. This information merely confirms what we have been told about the hazards of using these types of surfactants on our hair.
Another very important ingredient to avoid for long, curly hair especially is soaps. In the past, I have written an article cautioning users of soap to be careful, but basically concluding that it was probably okay to use soaps with an acidic rinse and lots of moisturizing agents. Based on the following information obtained from the research of Dr. Ali Syed (a hair care researcher who specializes in African and curly hair), I cannot in good conscience advocate use of any soap products on curly hair.
Soap molecules are salts of fatty acids found in plants and animal fats. They are somewhat alkaline and cause the hair to swell and the cuticle to raise up away from the surface of the hair shaft. These molecules are then able to penetrate through the cuticle and into the CMC where they neutralize the fatty acids in the lipid layer, rendering them water soluble. The fatty acids are then rinsed away in the shower and are gone forever. Use of soap to cleanse one's hair, especially long curly hair, seems to be a really effective way of permanently destroying the cuticle layer and making the hair very highly porous. This is an example of why natural may not always be superior. It is no surprise that researchers have invested years and many millions (billions) of dollars to develop more gentle cleansers for our hair.