Kentucky Cosmetology State Practice Exam 2025 – 400 Free Practice Questions to Pass the Exam

Ammonium thioglycolate is the correct choice for perming hair because it is a reducing agent specifically formulated to break down the disulfide bonds in hair. This chemical compound allows the structure of the hair to be altered, enabling it to hold a permanent wave or curl. When applied during the perming process, ammonium thioglycolate softens the hair, making it pliable enough to reshape into curls or waves with the aid of rollers or rods.

Other chemicals listed, while they each have their uses in hair treatments, do not serve as the primary active ingredient in traditional perming processes. Hydrogen peroxide is primarily used as an oxidizing agent in hair bleaching and coloring rather than perming. Sodium hydroxide is found in some chemical relaxers but is not typically used in perming processes. Glyceryl monothioglycolate is a milder alternative to ammonium thioglycolate and may be used in some perms, but ammonium thioglycolate remains the more commonly recognized chemical for this specific application in achieving permanent waves.