* Oxidizing agent: Hydrogen peroxide (H₂O₂) is the most common oxidizing agent. It works by penetrating the hair shaft and breaking down the natural melanin pigment that gives hair its color. Other oxidizing agents sometimes used include sodium percarbonate.
* Alkaline agent: This ingredient, often ammonium hydroxide (NH₄OH) or ethanolamine, opens the hair cuticle (the outer layer of the hair shaft) to allow the oxidizing agent to enter and react with the melanin. The alkaline agent also helps to activate and stabilize the oxidizing agent.
In addition to these two main components, hair bleach formulas may also contain:
* Stabilizers: These help to maintain the stability and effectiveness of the hydrogen peroxide.
* Conditioners and oils: These are added to help protect the hair from damage during the bleaching process. Common ingredients include mineral oil, silicones, or plant-based oils.
* Thickeners: These help to create a creamier consistency for easier application.
* Chelating agents: These help to remove metal ions from the hair, which can interfere with the bleaching process and cause damage.
* Fragrance: To mask the chemical smell of the other ingredients.
* Toners or dyes: Some bleach kits include toners or dyes to help neutralize unwanted tones (like yellow or orange) after the bleaching process.
* Persulfates: These boost the lightening power of the bleach. Common persulfates include ammonium persulfate, potassium persulfate, and sodium persulfate.
It's important to note that the exact ingredients and their concentrations can vary depending on the brand and type of bleach.