Figure 1. The breakage of the disulfide bridges of keratin allows for the formation of new disulfide bonds.

The key chemical necessary for hair depilation is based on an alkaline reducing agent that disintegrates the disulfide bonds (S-S) formed between cysteine units of keratin molecules in hair; this allows for the easy removal of hair by washing the skin surface. This depilatory action allows for the formation of new disulfide bonds (e.g., thioglycolic acid).