Cocamidopropyl Betaine

Cocamidopropyl betaine is an amphoteric surfactant commonly used in cleansers and shampoos (often ~1–10% active), and surfactants at these levels can measurably disrupt the stratum corneum and sting compromised skin, especially with frequent use. Clinically, CAPB is also a well-documented cause of allergic contact dermatitis in a subset of patients, often linked to manufacturing impurities (e.g., amidoamine/DMAPA), which elevates real-world risk beyond simple “mild” irritation. Given both barrier disruption potential and non-trivial sensitization risk in eczema-prone populations, it warrants careful use and patch testing. Safety Notes: In commercial personal-care products, cocamidopropyl betaine (an amphoteric surfactant typically supplied at ~30% active) is used at very low levels (~0.3–1%) as a foam booster/mildness modifier in low-foam facial cleansers, micellar/low-surfactant rinse-off washes, and some gentle shampoo/body wash systems. Mainstream rinse-off cleansers and shampoos commonly use it around 3–10% as part of the total surfactant blend, while high-foaming OTC shower gels, bubble baths, and clarifying shampoos can reach ~15–20% in finished formula (higher when the formulator leans heavily on CAPB as a primary/secondary surfactant). It is rarely used in true leave-on products and, when present, is generally kept at low levels due to irritation/eye-sting and residue considerations.