Washington Barber License Practice Exam

Sodium hydroxide is the primary ingredient in most hair relaxers because it effectively alters the structure of the hair. It is a strong alkaline agent that breaks down the disulfide bonds in the hair's protein structure. This process allows the hair to be reshaped and straightened. Sodium hydroxide is particularly favored for its efficiency in relaxing coarse and curly hair types, making it a widely used choice in professional salons.

Other ingredients like calcium hydroxide, potassium hydroxide, and magnesium hydroxide are indeed used in some formulations but are less common compared to sodium hydroxide. While they can also serve similar functions in relaxing hair, sodium hydroxide remains the most recognized and prevalent active ingredient in many traditional hair relaxer products.