The Easy Way To Cover Your Gray Hair, This type of dye is gentle, and it’s hard to mess up if you apply it yourself. When you’re looking to cover up grays, there are a few ways to do it. You can use a semi-permanent hair color if you want the color to last for just a few shampoos (great, for example, if you want quick coverage for a party). If you’re looking to make a long-term commitment, you’ll want to seek out permanent color. Rather than washing out, this type of dye needs to grow out of your hair-leaving dreaded gray roots in its wake.
But somewhere in the middle lies the hair color sweet spot that many women crave. It’s called demi-permanent hair color.
“This type of product will stay in the hair for 28 shampoos,” explains Teca Lewellyn, a Procter & Gamble Beauty Scientist. “So, depending on how frequently you wash your hair, it will take about a month to a month and half to gently fade away.”
Here’s how it works: Demi-permanent hair color molecules get under the outer cuticle of the hair shaft but, unlike permanent dyes, they don’t penetrate the deeper cortex. “They basically get temporarily stuck just beneath the cuticle until they are washed out,” says Lewellyn. “The difference with permanent color is that the dye has to swell the cuticle to make it lift and allow the molecules to make their way into the cortex deep inside the hair shaft.”
Demi-permanent may not be the answer for everyone and every hair situation, but it does have several key advantages.