Coloring your hair comes with major choices that go beyond the just-right shade you pick. You'll also need to decide between semi-permanent and permanent hair color. Semi-permanent hair color offers a lower-maintenance option that calls for less of a commitment. Because semi-permanent hair color doesn't have chemicals such as ammonia or peroxide, it doesn't penetrate your hair cuticle. As a result, semi-permanent hair color wears off in around three weeks. Semi-permanent hair colors such as glosses and glazes can boost your hair's shine, but they're not suited to major lightening or darkening projects. When you want to make an extensive change, you'll need to go with permanent hair color. Permanent hair color involves oxidation, or chemical processing, thanks to ammonia and hydrogen peroxide. Permanent hair color lasts around six to eight weeks, and it can darken, lighten, or change the tone of your hair.