Semi-permanent hair color does not contain peroxide so it can not lift the hair, therefore it can only make the hair darker and not lighter. The color will only last about six to twelve shampoos because it only deposits the hair color on the outermost layer of the hair. This is a good choice to try if you are afraid you may not like the color. Also, semi-permanent will enhance the shine and condition of the hair since it is not lifting.
Demi-Permanent hair color contains low amounts of peroxide which unlike semi-permanent, it can lighten the hair slightly. Demi-permanent deposits the color between the cuticle and cortex therefore making it last longer, anywhere from 12 – 26 washes.
Permanent hair color just as the name suggests, it is a permanent hair color and will last until the colored strands grow out. Permanent hair color can light hair up to 4 levels anything more than that is not recommended as it can cause damage to the hair.