National Occupational Competency Testing Institute (NOCTI) Cosmetology Practice Exam

Which chemical is most commonly used in hair relaxers along with ammonium sulfite and sodium hydroxide?

1. Hydrogen peroxide

2. Ammonium thioglycolate

3. Glycerin

4. Calcium hydroxide

The correct answer is: Ammonium thioglycolate

Ammonium thioglycolate is the chemical most commonly used in hair relaxers alongside ammonium sulfite and sodium hydroxide due to its effectiveness in breaking down the disulfide bonds in the hair’s keratin structure. This process allows the hair to be reshaped and straightened, making it more manageable for individuals with naturally curly or wavy hair. This method is particularly popular because ammonium thioglycolate is a milder alternative compared to some other chemicals, offering a degree of safety when used as directed. It works effectively in the process of perming as well, demonstrating its versatility in various hair treatments. Other options, such as hydrogen peroxide, glycerin, and calcium hydroxide, do not play the same role in hair relaxing. Hydrogen peroxide is primarily used in hair bleaching and color processing rather than straightening. Glycerin, while beneficial in moisturizing formulations, does not affect hair structure like relaxers do. Calcium hydroxide is used in some forms of relaxers, but it typically serves as a pH adjuster or in conjunction with other chemicals rather than as the main active ingredient. Thus, ammonium thioglycolate remains the leading choice for effective hair relaxing in conjunction with the mentioned compounds.