The Best Way to Hide Gray Hair, According to Stylists

Bring out the big guns: if you want "100 percent full gray coverage," according to Hazan, then you're going to have to dedicate a few hours to the cause. "Permanent color has peroxide, which lightens the hair," Hazan explained. "Expect your color to last around four to six weeks." So if you want a blissful month with zero shades of gray on your head, step right this way.