Users of semi-permanent or temporary hair color can expect their color to last for about 6 weeks. Color fades with shampooing and exposure to air.
It may be difficult to decide whether to use a semi-permanent or permanent hair color, especially for the first-time user. Semi-permanent hair color can actually be more damaging to the hair because it has to be reapplied more often. Semi-permanent color may be right for someone who only wants a temporary change and doesn't want the hassle of having to mix the right color. Because semi-permanent hair colors don't contain bleach, they cannot be used to lighten hair.
Permanent hair color uses oxidation agents, such as ammonia and hydrogen peroxide, to color the hair. It can be used to lighten or darken hair and lasts much longer than semi-permanent hair color. There is usually a wider range of color options available but, because the chemicals used in these formulas is stronger, they can be very damaging to the hair.
No matter which method of coloring is used, some damage and breakage will occur. This is because hair color reduces the elasticity of the hair, resulting in more breakage. After coloring, stylists recommend using a deep conditioning treatment prior to and after coloring.