Which chemical is commonly used in the perming process?

Ammonium thioglycolate is widely recognized as the primary chemical used in the perming process. This chemical serves as a reducing agent in the procedure, effectively breaking the disulfide bonds in the hair's keratin structure. By breaking these bonds, the hair can be reshaped to create curls or waves when it is wrapped around rods or other styling tools and then neutralized.

During the perming process, hair is first treated with ammonium thioglycolate, which softens the hair and allows it to be molded into the desired shape. Following this, a neutralizing solution—often containing hydrogen peroxide—is applied to reform the disulfide bonds in their new configuration, thus setting the curls or waves.

Other options, while related to hair treatments, serve different purposes. Hydrogen peroxide is commonly used in coloring processes and as a developer in hair dyes but is not the primary agent for perming. Sodium hydroxide is typically associated with chemical relaxers, which straighten hair rather than curl it. Glyceryl monothioglycolate is a milder alternative used in certain formulations, but ammonium thioglycolate remains the most standard and effective agent for classic perming techniques.