Safety to human skin of cocamidopropyl betaine: A mild surfactant for personal‐care products

Cocamidopropyl betaine (CAPB) is a mild surfactant used in shampoos, conditioners, body washes, and other personal‐care products. Several recently published case reports have suggested that CAPB may be a skin sensitizer. A 6‐wk product‐use study was conducted to determine whether subjects with previous positive patch tests to CAPB could use personal‐care products (prototype hair shampoo, liquid handsoap, and body wash) with this surfactant without problems. Post‐study patch testing suggested that amidoamine, a material used in the synthesis of CAPB and a contaminant of CAPB preparations, is a likely sensitizer. However, patch testing did not rule out the possibility that CAPB itself may be an allergen to a small number of presensitized individuals. It is recommended that CAPB with minimal levels of contamination be used for the formulation of personal‐care products.