What oxidizing agent is commonly used in hair bleach?

Hydrogen peroxide is the oxidizing agent commonly used in hair bleach. It lightens hair by oxidizing melanin, the natural pigment responsible for much of hair’s color.

Commercial bleaching products commonly combine hydrogen peroxide with persulfate salts. An alkaline ingredient such as ammonia or monoethanolamine helps swell the hair’s cuticle and allows the bleaching mixture to penetrate more effectively. The peroxide then breaks down pigment molecules inside the hair shaft.

The result is gradual color change rather than an instant jump to white. Very dark hair may pass through brown, red, orange, orange-yellow, and yellow stages before becoming pale yellow. Hydrogen peroxide strength varies: home products often contain about 6% peroxide, while salon products can reach roughly 9%.

A common mix-up is sodium hypochlorite, the active ingredient in household bleach. It is not used for normal hair bleaching and can seriously damage hair and skin. Ammonia is also important in many formulas, but it is an alkalizing agent, not the primary oxidizer.