Identify the most commonly used reducing agent in permanent waving and relaxing processes.

• A. Thioglycolate Acid
• B. Sodium Hydroxide
• C. Hydrogen Peroxide
• D. Ceric Ammonium Nitrate

Answer: (A)

The main idea is that the reducing agent in chemical texture services is what breaks the hair’s disulfide bonds so the hair can be reshaped. Thioglycolate salts, such as ammonium thioglycolate, provide thiol groups that donate electrons to the disulfide bonds (S-S), converting them to broken, more flexible cysteine forms. This reduction lets the hair take on a new shape around rods during permanent waving or be straightened in relaxing. After shaping, a neutralizer—typically hydrogen peroxide—oxidizes the thiol groups back into new disulfide bonds, “setting” the new texture.

The other options aren’t the reducing agent used for this purpose. Sodium hydroxide is a strong base used to raise pH in some relaxers and helps break bonds by swelling and saponifying keratin, not by reducing disulfide bonds. Hydrogen peroxide acts as the oxidizer in neutralization, not as the reducing agent. Ceric ammonium nitrate is an oxidizer used in other processes, not the standard reducing agent for waving or relaxing.