The safety of cocamidopropyl betaine and related amidopropyl betaine ingredients has been assessed on several occasions by the Expert Panel for Cosmetic Ingredient Safety.

In 1991, the Expert Panel concluded that CAPB was safe for use in rinse-off cosmetic products at the levels of use reported in the available literature. Due to the potential for skin irritation at higher use concentrations, however, the Expert Panel recommended that for cosmetic products intended to remain on the skin for long periods of time (i.e., leave-on products), the concentration of CAPB should not exceed 3%.

Based on new information showing a substantial increase in the number of uses of CAPB, including new uses in aerosol products and reports of allergic skin reactions in patients who used rinse-off products, the Expert Panel undertook an additional review of CAPB and related amidopropyl betaines in 2012. The primary inquiry for the 2012 review related to the presence of the 3,3-dimethylaminopropylamine (DMAPA) and fatty acid amidopropyl dimethylamine (amidoamine) in CAPB and other related amidopropyl betaines. DMAPA and amidoamine are present in CAPB and other related amidopropyl betaines as manufacturing by-products. DMAPA and amidoamine can sometimes cause allergic skin reactions (i.e., dermal sensitization).  However, literature reviewed by the Expert Panel has shown that when the levels of DMAPA and amidoamine are reduced, the number of people reacting is also reduced. Based on its review of the published scientific literature, the Expert Panel concluded that cosmetics using CAPB and related amidopropyl betaines were safe as long as they were formulated to be non-sensitizing.  The Expert Panel also advised industry to continue minimizing the concentration of these manufacturing by-products.

CAPB and related amidopropyl betaine ingredients have the potential to form by-products called nitrosamines. Nitrosamines are organic substances formed by the reaction of an amine (such as a protein in foods or an amine side group on a cosmetic ingredient) with what is called a nitrosating agent (such as nitrites that are used in foods as preservatives). This potential of certain ingredients to form nitrosamines in the presence of a nitrosating agent is well known to both industry and regulators. The Expert Panel recommend that CAPB and related amidopropyl betaines not be used in products that also contained nitrosating agents. This is standard practice for manufacturers of cosmetics and personal care products.

Learn more about Nitrosamines.