Cocamidopropyl Betaine vs Sodium Laureth Sulfate: which is worse?

What is Cocamidopropyl Betaine?

Cocamidopropyl betaine is an amphoteric (zwitterionic) surfactant derived from coconut oil and dimethylaminopropylamine. It serves as both a primary and secondary surfactant and is known for being gentler than traditional sulfate surfactants. It also has antistatic and conditioning properties.

What is Sodium Laureth Sulfate?

Sodium laureth sulfate (SLES) is an anionic surfactant derived from ethoxylated lauryl alcohol, widely used as a primary lathering and cleansing agent. It is milder than its close relative SLS because the ethoxylation process reduces skin irritation potential. SLES is one of the most common cosmetic surfactants globally.

Documented risks

Cocamidopropyl Betaine: CAPB itself is well-tolerated by most people. However, it was named Allergen of the Year by the American Contact Dermatitis Society in 2004, indicating it can cause contact allergic reactions in a subset of sensitized individuals. The sensitizer is typically not CAPB itself but trace impurities from manufacturing (amidoamine or 3-dimethylaminopropylamine). High-purity CAPB has a very low sensitization rate. It is not a carcinogen or endocrine disruptor. The CIR concluded CAPB is safe for cosmetic use.

Sodium Laureth Sulfate: SLES is broadly considered safe at cosmetic use levels (typically 1–20%). The Cosmetic Ingredient Review (CIR) Expert Panel concluded it is safe as used in rinse-off products. A known manufacturing byproduct, 1,4-dioxane, can appear at trace levels; reputable manufacturers use vacuum-stripping to minimize it below regulatory limits. SLES does not penetrate intact skin significantly and is not a carcinogen or systemic toxin. Some individuals with very sensitive or eczema-prone skin may experience mild irritation at higher concentrations; this resolves upon rinsing. It is not a hormone disruptor and does not accumulate in the body.