You may have many questions when you're thinking about dyeing your hair. The most essential might relate to the type of hair dye you should use. Not all dyes are created equal, and the choice you make determines how your color looks, how your hair looks, and how long the color lasts. Understand the differences between semi-permanent and demi-permanent hair color before you try a new look.
When to Choose Semi-Permanent
Semi-permanent hair color is good for first-time dyers or those who aren't looking to make a drastic change. Semi-permanent dye has no ammonia and no developer, so no color is deposited inside the hair shaft. Instead, the color coats the hair, which is why it's often referred to as a "stain" or "wash." Semi-permanent color is good for changing or enhancing tones -- but not for changing colors. It generally washes out in six to 12 shampoos.
When to Choose Demi-Permanent
Demi-permanent hair color results in a more obvious change for some who wants to avoid damage or anything drastic. It contains no ammonia but does have a small amount of peroxide, which opens the hair cuticle slightly so that some color will be absorbed. Demi-permanent does a better job of darkening hair than semi-permanent does, but it doesn't lighten hair. Demi-permanent hair color will fade and typically last 12 to 24 shampoos.
What's the Damage?
If you're concerned about damage to your hair, avoid demi-permanent color. While the damage it causes is minimal, it's still more of a risk than with semi-permanent hair color. Because demi-permanent color opens up the cuticle slightly, there is a chance hair will feel frizzy and dry afterward. Semi-permanent color only coats the hair strand, and the effects wash out quickly.
Covering the Gray
Both semi- and demi-permanent dyes effectively cover gray, although demi-permanent is much better at it. Semi-permanent is acceptable for hair that is minimally gray or just starting to lose color. It won't be a long-lasting solution, however. Demi-permanent will color the gray better and for longer.
Because both semi- and demi-permanent hair color fades quickly, take proper steps to ensure that the color lasts as long as possible. Use moisturizing shampoos and conditioners; avoid shampooing every day, if possible; and cover your hair when going outside to shield it from the sun, which accelerates the fading process. Also, tie your hair back when working out, doing chores or any other strenuous activity, as excess sweat in your hair will cause the color to rinse out.