Semi-Permanent Colors contain only vegetable extracts and natural ingredients, so no color is stripped from your hair. It is similar to henna but it doesn't coat the hair but adds shine to hair. It washes out in 6 to 12 shampoos, contains no potentially damaging peroxide or ammonia, and, once its gone, leaves your hair the same color as it was before being colored. This means you can experiment with shades until you find one you want to use consistently. Because of its gentle nature, however, semi- permanent color can't change things very dramatically It has a slightly translucent quality that makes it better suited to enhancing rather than altering your natural color.
Demi-Permanent hair colors which some people mistakenly call semi-permanent will lasts from 12 to 24 shampoos. It contains a small amount of peroxide but no ammonia.