Q: When I dye my gray hair, the brunette color doesn't take all over. Help!
A:There are a few things you can do to prevent your hair from suffering from Teflon syndrome when it comes to color. First, be sure the product you're using is a permanent and not a demi- or semi-permanent formula, says colorist Marie Robinson of the Marie Robinson Salon in New York City. Most permanent color contains ammonia and peroxide, which penetrate the hair shaft, staining it. (L'Oréal recently introduced INOA, a salon-only permanent dye that contains no ammonia but works the same way.) Choose a dye that's labeled "neutral" or "natural"; these colors have the densest pigment and cover gray better than dyes called "gold" or "ash." Also, rather than use the squeeze bottle provided in the box to apply the dye, empty it into a nonporous bowl and use a tinting brush with coarse bristles (you can find one for $1 to $2 at a beauty supply store). The brush will roughen the cuticle of the gray hairs, making it easier for the dye to penetrate, says Robinson. Finally, leave the formula on for at least the recommended time, if not a little longer.
Keep in mind: You might enlist a friend to check the top and back of your head so you don't miss any gray.