* Permanent Hair Dye: This type of dye typically contains ammonia and peroxide (a bleaching agent). The ammonia opens the hair cuticle, and the peroxide lightens the natural hair color, allowing the dye to deposit.
* Demi-Permanent Hair Dye: Demi-permanent dyes contain a low volume of peroxide, which allows them to deposit color and subtly blend grays. Demi-permanent color does not lift, or lighten, the hair.
* Semi-Permanent Hair Dye: Semi-permanent dyes do not contain ammonia or peroxide. They deposit color onto the hair shaft without altering the natural hair color. Semi-permanent dyes are designed to coat the hair and fade gradually with each wash.
* Temporary Hair Dye: Similar to semi-permanent dyes, temporary dyes do not contain ammonia or peroxide. They provide a temporary color change that washes out easily.
So, whether a hair dye has bleach (peroxide) depends on whether it's designed to lighten the hair or simply deposit color.