3% peroxide
- Darkening of hair by 1 level.
- It only works if you are going from a lighter to a darker shade, not the other way round.
- Adds a shade or tint to hair of the same lightness level.
6% peroxide
- Offers lifting by 1-2 levels.
- The most common force of developer. It is usually used with temporary color and permanent dye.
- Also suitable for covering 100% white hair.
9% peroxide
- Lightens up to 3 levels.
- Used for dyeing and also for lightening hair. Suitable for coloring grey hair.
- The most often it is mixed with permanent color and lightening cream or powder.
12% peroxide
- Serves only for lightening. Up to 8 levels of lift.
- Ideal for a super platinum blonde result.
- It is used together with a lightening cream or powder.
- There is a risk of hair burns. You should never use a 40 volume developer at home.