South Carolina Barber Practice Exam

What is the main ingredient in most hair relaxers?

1. Calcium hydroxide

2. Sodium bicarbonate

3. Sodium hydroxide

4. Ammonium thioglycolate

The correct answer is: Sodium hydroxide

The primary ingredient in most hair relaxers is sodium hydroxide. This chemical compound is highly alkaline and functions effectively in altering the structure of the hair. Sodium hydroxide works by breaking down the disulfide bonds in the hair's keratin, allowing the hair to be straightened and reshaped. This ingredient is favored in many relaxers due to its power and speed in breaking down hair proteins, which is essential for achieving the desired straightened look. The use of sodium hydroxide allows for significant changes to the hair texture, especially in naturally curly or frizzy hair. While calcium hydroxide, sodium bicarbonate, and ammonium thioglycolate are also chemicals associated with hair treatments, they are not the main components in traditional relaxers. Calcium hydroxide is often found in some formulations but typically works in conjunction with sodium hydroxide in the no-lye relaxers. Sodium bicarbonate is known more for its role as a mild alkaline agent or pH adjuster rather than as a primary relaxer ingredient. Ammonium thioglycolate is primarily used in perming solutions rather than in relaxers targeting straightening, making sodium hydroxide the most recognizable and widely used active ingredient for that specific purpose.