Washington Barber License Practice Exam

What chemical is commonly used in hair straightening treatments?

1. Hydrogen peroxide

2. Sodium bicarbonate

3. Sodium hydroxide

4. Ammonium thioglycolate

The correct answer is: Sodium hydroxide

The chemical commonly used in hair straightening treatments is sodium hydroxide. This stronger alkaline compound serves as a powerful relaxer by breaking down the protein structure in the hair, allowing it to be reshaped and straightened. Sodium hydroxide effectively alters the hair’s texture, making it a popular choice for clients seeking permanent straightening solutions. Unlike the other options, sodium hydroxide provides a strong enough chemistry to manage coarse and resistant hair types effectively. Other chemicals like ammonium thioglycolate are more typically associated with relaxing treatments or soft waves, while hydrogen peroxide primarily functions as a bleaching agent. Sodium bicarbonate is often used as a pH adjuster or mild exfoliant but is not a central ingredient in hair straightening processes. Therefore, sodium hydroxide is distinguished as the primary agent for achieving straightened hair in professional treatments.