Alaska Barber Certification Practice Exam 2025 – All-in-One Resource to Master Your Certification!

Ammonium thioglycolate is the chemical commonly used in permanent wave solutions because it serves as a reducing agent that breaks disulfide bonds in the hair. This process allows the hair to be reshaped and styled into curls or waves. When the solution is applied to the hair, it penetrates the hair shaft and alters the protein structure, creating a new shape as it is set in curlers or rods.

In contrast, the other substances listed do not serve the same purpose in the permanent waving process. Sodium chloride is typically used as a thickener or stabilizing agent in various products but does not alter the hair's structure in the way required for permanent waving. Hydrogen peroxide is primarily an oxidizing agent, often found in hair bleaching products rather than in permanent waves, as it can damage the hair if used improperly. Glycolic acid is an alpha hydroxy acid generally used in skincare and exfoliating products but does not function in the structural alteration required for permanent waves.