The science
Rinse-off cleanser performance and tolerance are determined largely by the surfactant system, and this wash uses a mild one. Sodium cocoyl isethionate is an anionic surfactant derived from coconut fatty acids and isethionic acid, with a large body of comparative data showing lower protein denaturation, lower lipid extraction and lower irritation scores than sodium lauryl sulfate, and a creamy lather that made it the basis of the first mild syndet bars. Cocamidopropyl betaine is an amphoteric surfactant that improves foam and reduces the irritation potential of anionics in blends; sodium methyl lauroyl taurate and sodium lauroyl isethionate further down are similar mild anionics. Because the system is buffered near skin pH rather than alkaline, it produces less increase in transepidermal water loss and less barrier disruption than true soap in repeated-use studies, which is the mechanistic basis for the softer after-feel and for its suitability on darker skin, where lipid stripping shows as visible ashiness.
The moisturising claim rests on glycerin at the fifth position, which is deposited on the skin during washing and modestly raises hydration for a short period, and on the superfatting lipids, Fair Trade shea butter and coconut oil at eighth and ninth, which leave a trace of lipid after rinsing; sodium stearoyl lactylate, stearic and palmitic acids assist emulsification and add creaminess, and guar hydroxypropyltrimonium chloride is a cationic polymer that deposits on skin for a smooth after-feel. Aloe leaf juice powder, second in the list, and coconut fruit extract and acacia senegal gum at tenth and eleventh contribute polysaccharides with soothing and film-forming properties in leave-on contexts; in a wash with a residence time of under a minute their effect is minimal. A 24-hour moisturisation claim is not supported by published data for any rinse-off product.
Tolerance considerations are specific. The fragrance at seventh declares benzyl salicylate, coumarin, limonene and linalool, all listed allergens under EU cosmetic regulation; limonene and linalool form hydroperoxides on air exposure that are more potent sensitisers than the parent compounds. Cocamidopropyl betaine is a documented contact sensitiser, typically via amidoamine and dimethylaminopropylamine impurities, and appears regularly in patch-test series for scalp, face and body cleansers. Coconut oil is comedogenic in leave-on form but of limited relevance in a rinse-off. SheaMoisture publishes no product-specific clinical or instrumental testing.