ABSTRACT

Exposure of consumers to cosmetic products mainly occurs via the dermal route. Once a chemical contacts skin, absorption begins. Diffusion into and through the stratum corneum typically is the rate limiting step in percutaneous absorption. However, the rate-limiting barrier to absorption is dependent upon the specific chemical. For a cosmetic chemical that is applied to skin, the accuracy of the risk assessment can be improved by basing the potential systemic exposure on an estimate of the dermal exposure that has been corrected with skin absorption data (1). Dermal exposure to a cosmetic ingredient is a function of the concentration of chemical contacting skin and the duration of skin contact. Leave-on cosmetic products would represent the category of products resulting in large dermal exposures, while rinse-off product use results in dermal exposures that are brief and discontinuous.