What is the main ingredient in most hair bleaching products?

The main ingredient in most hair bleaching products is hydrogen peroxide. This compound acts as a strong oxidizing agent that breaks down the melanin, the natural pigment in hair, thereby lightening the hair color. When hydrogen peroxide is applied to hair, it penetrates the hair shaft and causes a chemical reaction that decolorizes the hair, making it possible to achieve various shades of blonde or even to lighten dark hair significantly.

While ammonia is often included in hair bleaching products to help open the hair cuticle and allow for better penetration of the bleaching agent, it is not the primary lightening agent itself. Alcohol and glycolic acid do not serve the main purpose in hair bleaching, as alcohol is typically used for its solvent properties and glycolic acid is used primarily as an exfoliant in skin care rather than for altering hair color.