Final answer:
Chemical depilatories use a thioglycolic acid derivative, specifically calcium thioglycolate, to break down the disulfide bonds in keratin, resulting in hair that can be easily wiped away. The process requires about 10 minutes, after which hair regrowth is possible as the treatment does not affect the dermal papilla.
Step-by-step explanation:
The main ingredient in chemical depilatories that helps to soften and degrade the protein structure of hair is indeed a thioglycolic acid derivative. These depilatory products contain active ingredients like salts of thioglycolic acid and thiolactic acids which break disulfide bonds in keratin, weakening the hair so it can be easily removed. The main chemical reaction involves thioglycolic acid reacting with cystine in the hair to form dithiodiglycolic acid and cysteine.
Chemical depilatories often contain 5-6% calcium thioglycolate in a cream base, which prevents the product from running off the skin. They also contain alkaline substances like calcium or strontium hydroxide to maintain a high pH level (around 12), aiding in the efficient breakdown of hair. It usually takes about 10 minutes for the hair to be destroyed, after which the skin is rinsed and treated with conditioners to restore natural pH levels.
It's important to note that while depilatories effectively remove hair, they do not destroy the dermal papilla, which means hair will grow back. These products come in various forms, such as gels, creams, lotions, aerosols, roll-ons, and powders, being marketed under brand names like Nair, Magic Shave, and Veet.