Thioglycolic acid is the organic compound

Organic compound

An organic compound is any member of a large class of gaseous, liquid, or solid chemical compounds whose molecules contain carbon. For historical reasons discussed below, a few types of carbon-containing compounds such as carbides, carbonates, simple oxides of carbon, and cyanides, as well as the...

 HSCH₂CO₂H. It contains both a thiol

Thiol

In organic chemistry, a thiol is an organosulfur compound that contains a carbon-bonded sulfhydryl group...

 (mercaptan) and a carboxylic acid

Carboxylic acid

Carboxylic acids are organic acids characterized by the presence of at least one carboxyl group. The general formula of a carboxylic acid is R-COOH, where R is some monovalent functional group...

. It is a clear liquid with a strong unpleasant odor. It is readily oxidized by air to the corresponding disulfide

Disulfide

In chemistry, a disulfide usually refers to the structural unit composed of a linked pair of sulfur atoms. Disulfide usually refer to a chemical compound that contains a disulfide bond, such as diphenyl disulfide, C6H5S-SC6H5....

 [SCH₂CO₂H]₂.

TGA was developed in the 1940s for use as a chemical depilatory and is still used as such, especially in salt forms, including calcium thioglycolate and sodium thioglycolate.