PSI Barbering Practice Exam

In hair lightening processes, what substance oxidizes the melanin pigments in hair, leaving the hair lighter in color?

1. Hydrogen Peroxide

2. Ammonia

3. Water

4. Saline Solution

The correct answer is: Hydrogen Peroxide

In hair lightening processes, hydrogen peroxide acts as the key oxidizing agent. Its primary function is to break down melanin pigments, which are responsible for the natural color of the hair. When applied to the hair, hydrogen peroxide releases oxygen, which interacts with the melanin and alters its chemical structure. As a result, the pigments become less colored, leading to a lighter appearance of the hair. Ammonia is often used in conjunction with hydrogen peroxide to open the hair cuticle and allow for better penetration of the lightening agents, but it does not play a direct role in oxidizing the melanin itself. Water does not serve any active purpose in lightening hair color, as it simply acts as a solvent. Similarly, saline solution does not contribute to the hair lightening process, as its composition lacks the properties necessary for the oxidation of hair pigments. Thus, hydrogen peroxide is the correct answer due to its effective role in altering the color of the hair by oxidizing melanin.