Amended Final Report on the Safety Assessment of Hydroxystearic Acid¹

Abstract

Hydroxystearic Acid is a fatty acid used as a surfactant–cleansing agent in cosmetic products. Initial review of available safety test data resulted in a finding that there were insufficient data to support the safety of Hydroxystearic Acid for use in cosmetic products. Data needed included concentration of use, chemical characterization, dermal reproductive and developmental toxicity, genotoxicity (and carcinogenicity data if the genotoxicity data were positive), and shin irritation data. Subsequent to that conclusion, new data were received. Use concentrations were reported as high as 10%. Small amounts of other fatty acids are commonly found in preparations of Hydroxystearic Acid. Genotoxicity was not found in bacterial or mammalian systems and only subcutaneous sarcomas at the site of injection were found in carcinogenicity studies. Dermal reproductive and developmental toxicity studies were negative. Skin irritation was produced by antiperspirant prototype formulations containing Hydroxystearic Acid under occluded or semioccluded patch test conditions. It was considered that such formulations under those exaggerated conditions can be irritating, but are generally not irritating in actual use. Because Hydroxystearic Acid and Stearic Acid are structurally similar, data from a previous safety assessment of Oleic Acid, Lauric Acid, Palmitic Acid, Myristic Acid, and Stearic Acid were summarized. On the basis of the animal and clinical data, it was concluded that Hydroxystearic Acid is safe as a cosmetic ingredient in the present practices of use.