Colorado Cosmetology Written Practice Exam

The most common active ingredient in chemical relaxers that is often used to permanently relax curly hair into a straighter configuration is indeed sodium hydroxide. This substance is classified as a lye relaxer and has been widely utilized in the cosmetology industry for its effectiveness in breaking down the protein structure of the hair, which allows for a significant change in curl pattern.

While ammonium thioglycolate is used in some relaxers, it typically serves as a more gentle alternative and is often associated with curl permanents rather than straightening. Calcium hydroxide and potassium hydroxide also serve as active ingredients in specific types of relaxers, but sodium hydroxide remains the most predominant choice among professionals due to its strong efficacy in achieving straight hair.