Final Report on the Safety Assessment of Ammonium and Glyceryl Thioglycolates and Thioglycolic Acid

Abstract

Ammonium and Glyceryl Thioglycolates and Thioglycolic Acid are used predominantly in cosmetic permanent waving lotions at concentrations up to 15.4% (as Thioglycolic Acid). At use concentrations, these cosmetic ingredients are only slightly toxic in acute single oral and dermal exposures. In repeated dermal tests for extended periods of exposure, these ingredients were toxic. Commercial permanent wave products produced transient conjunctival redness to both rinsed and unrinsed eyes. The results of skin testing for irritation and sensitization of these Thioglycolates depends on the type of test system used. Under occlusive patch testing, the data indicate that these ingredients are cumulative irritants and possibly weak sensitizers, but not under semi-occlusive test conditions. In clinical patients, mainly hairdressers, Glyceryl Thioglycolate elicited allergic reactions at concentrations down to 0.25%. It is concluded that these cosmetic ingredients may be safely used at infrequent intervals. However, hairdressers should avoid skin contact.