1. Lifting the Cuticle:
- Hydrogen peroxide is a strong oxidizing agent. It swells the hair cuticle (the outer layer of the hair shaft), making it more porous. This allows the color molecules to penetrate deeper into the hair cortex (the middle layer).
2. Decolorization:
- Peroxide also breaks down melanin, the natural pigment in hair. This process lightens the hair, creating a base for the new color to be deposited on. The amount of lifting depends on the concentration of peroxide and the processing time.
3. Allowing Color Deposition:
- Once the hair is lifted, the color molecules in the hair dye can bind to the hair shaft. The color molecules are attracted to the hair's keratin protein, forming a bond that gives the hair its new color.
In summary, hydrogen peroxide:
* Doesn't deposit color directly. It prepares the hair shaft by lifting the cuticle and lightening the existing pigment.
* Allows the color molecules to penetrate deeper and create a more permanent bond with the hair.
Important Note:
* Hydrogen peroxide can be damaging to the hair if used improperly. It's crucial to use the correct concentration and processing time, and to follow the instructions on the hair dye packaging.
* If you're unsure about using hydrogen peroxide on your hair, consult a professional hairstylist.