Colorado Cosmetology Written Practice Exam 2025 - Free Cosmetology Practice Questions and Study Guide

Ammonium thioglycolate is a common ingredient in chemical relaxers and is typically formulated within a specific pH range to effectively break the disulfide bonds in the hair that are responsible for its curl. The correct pH range associated with a relaxer containing ammonium thioglycolate is commonly between 9.0 to 9.6. This higher pH level helps to swell the hair and allow the chemical to penetrate effectively, leading to a straightening effect by altering the hair structure.

In contrast, the other ranges mentioned do not align with the characteristics and effectiveness of ammonium thioglycolate. For instance, a pH range of 4.5-7.0 is considered acidic and is more suitable for conditioners or treatments but not for relaxers that need to break down the hair structure. Similarly, pH ranges of 9.6-10.0 and 10.0-12.0 are too high, making the solution potentially damaging to hair and scalp if not used properly. Thus, the pH range of 9.0-9.6 ideally suits the purpose of an ammonium thioglycolate relaxer.