Based on the available data, the CIR Expert Panel concluded that ... Ethyl Thioglycolate is safe for use in hair straighteners, permanent waves, tonics, dressings, and so forth, wave sets, other non-coloring hair products, and hair dyes and colors, as described in this safety assessment, at concentrations up to 15.2% (as Thioglycolic Acid). Hairdressers should avoid skin contact and minimize consumer skin exposure.
Formula
C4H8O2S
Mol. Weight
120.17
CAS #
623-51-8
Form
Liquid
State
Colorless liquid with a stench; [Alfa Aesar MSDS]
Functions
Depilatory
Hair Waving Or Straightening
Reducing
Moisturizing
Strengthens Barrier
Changes hair texture
Removes unwanted hair
Chemical reduction
Traditional Use
Developed as a reducing agent in the 1940s-1950s. Became the standard active ingredient in chemical hair relaxers and permanent wave solutions due to its ability to break disulfide bonds in hair.