The neutralizer used in Thio (thio) relaxers is an oxidizing agent, usually which chemical?

• A. Hydrogen peroxide
• B. Sodium hypochlorite
• C. Sodium thiosulfate
• D. Ozone

Answer: (A)

The needed step after the reducing action in thio relaxers is to re-form the hair’s disulfide bonds by oxidation, which “locks in” the new shape. Hydrogen peroxide is the typical oxidizing agent used as the neutralizer because it effectively accepts electrons from the reduced sulfur atoms, converting them back into disulfide bonds and stabilizing the straightened structure. This oxidation stops the reducing process and restores the hair’s cross-links in their new arrangement.

Sodium hypochlorite would be far too harsh and would bleach or damage hair. Sodium thiosulfate acts as a reducing agent in many contexts, not as the oxidizing neutralizer needed here. Ozone is not used in standard cosmetic neutralizers due to safety concerns and practicality.