Hair Coloring and Damage
A: All permanent hair coloring processes use hydrogen peroxide to develop the color. This has the effect of raising the cuticle layer to enable the penetration of the hair shaft by the color molecules. Even deposit-only permanent hair color raises the cuticle. This can be damaging to your hair.
A raised cuticle allows moisture to pass into and out of the hair more readily. Many of the hair coloring kits on the market today include acid-balancing conditioners for use after coloring to "seal" the hair. This means that they help to contract the cuticle layer back to a more normal state. This makes the color last longer and also helps the hair to stay healthier and retain its necessary moisture.
The best hair color formulas include conditioning agents in the hair color itself, which in a deposit-only hair color (where the hair's level is not lightened at all) can leave the hair feeling healthier than before it was colored. The key is to choose your hair color wisely and be wise about the results you want to achieve.
You should never try to lift your hair's level more than 3-to-4 levels in one process. I, personally, recommend that women never try to lift their level more than 3-to-4 levels, period. Even with jet-black hair, 3-to-4 levels of lift are sufficient to give you a wide variety of colors to choose from. To try to lift the hair further (for example, from dark brown to pale blonde) is only asking for trouble.
Remember, once hair has been too severely damaged, there is nothing that can be done to repair it and you can only minimize the appearance of the damage.
©hairfinder.com
See also:
How to color hair
How decolorizing hair works
How to recognize hair with damage
Does semi-permanent hair color damage hair?