By Kayleigh Donahue, REDBOOK.
1. Shampoo before you dye. The old idea that it's best to color your hair when it's dirty? Not true. Whether you're hitting the salon or coloring at home, "dye will absorb best when hair is freshly washed, so there are no oils or product buildup standing in its way," says colorist Rita Hazan, who works with Jessica Simpson.
Related: Date-Night Dresses Under $100
2. Wash less often--but with the right stuff. Every time water seeps out of your strands' cuticles, it takes dye molecules with it, resulting in dulled-down color. Now, shampoos and conditioners for color-treated hair are targeting this very problem--like the new formulations of John Frieda Sheer Blonde, Brilliant Brunette, and Radiant Red color-protecting shampoos and conditioners ($6.50 each). The shampoos help trap water molecules before they can do any damage, while the conditioners contain a special silicone that locks dye in and water out.
Related: 100 Hot Celebrity Hairstyles For Every Hair Type
3. Blow-dry! Surprising, right? "Research shows that air-dried hair experiences a more significant shift in color than hair that's been blown dry," says cosmetic chemist Ni'Kita Wilson. Again, it's all about the water--air-dried hair is wetter for longer, so the theory is that the color has more time to escape. But before you pick up the dryer, mist on a heat-protecting spray, like Tresemmé Platinum Strength Heat Protect Spray ($5.69) to guard against hot-air damage.
More from REDBOOK: