South Dakota Cosmetology Practice Exam

The correct answer is based on the understanding of the primary types of chemical relaxers used in cosmetology. Sodium hydroxide and ammonium thioglycolate are the two main categories that are frequently utilized for hair relaxing treatments.

Sodium hydroxide is known as a lye relaxer, which works by breaking down the disulfide bonds in the hair, allowing it to be reshaped and straightened. This type of relaxer is effective for coarse, curly hair and is often associated with stronger formulations that require careful application to avoid damage.

Ammonium thioglycolate, on the other hand, is classified as a no-lye relaxer. It is considered milder compared to sodium hydroxide and is often used for finer hair textures. This relaxer involves a different chemical process but also breaks down disulfide bonds, albeit in a gentler manner.

The other options include chemicals that do not align with the primary categories of hair relaxers. Calcium hydroxide and ammonium sulfate are not widely recognized as standard relaxers, while glyceryl monothioglycolate and lithium hydroxide combinations serve different purposes in hair treatments. Hydrogen peroxide and ethyl alcohol do not function as relaxers but are used in different cosmetic