Sodium Cetearyl Sulfate

Sodium cetearyl sulfate is an anionic surfactant/emulsifier used in cleansers and some creams (often ~0.5–5%), and sulfate surfactants are well documented to disrupt the stratum corneum lipids and increase transepidermal water loss. Human patch/usage testing and clinical experience show higher rates of stinging, dryness, and irritant contact dermatitis in atopic/eczema-prone patients compared with non-ionic or amphoteric alternatives, especially with leave-on exposure or frequent use. Given its barrier-disruptive mechanism and predictable flare risk in compromised skin, it warrants a significant irritancy score. Safety Notes: In commercial products, sodium cetearyl sulfate is most often used as a primary or co-emulsifier/surfactant, with low-end use (~0.2–1%) in leave-on creams/lotions where it mainly supports emulsification and texture. Higher levels are seen in rinse-off cleansing creams, shampoo/body wash formats, and some solid cleanser bars where total anionic surfactant load is high, with consumer-available formulas reaching ~8–12% when SCS is a major surfactant. There is no specific EU/FDA concentration cap for this ingredient in cosmetics; practical limits are driven by irritation potential, foam/viscosity targets, and stability.