These Purple Shampoos Will Keep Your Hair Bright Between Salon Visits

When it comes to hair, there’s nothing better than fresh color. The challenge? Maintaining that just-left-the-salon level luster until your next dye job. Blondes in particular may notice signs of brassiness over time. This yellow-orange cast can be caused by a number of things, including "your color oxidizing over time, exposure to UV light, chlorine, and even traces of copper in your water,” explains Meri Kate O’Connor, celebrity colorist at Loft 647 in West Hollywood, California.

This is where a purple toning shampoo can help. So what exactly does it do and what is it good for? Purple shampoos deposit a sheer violet tint on strands that helps cancel unwanted yellow or brassy tones according to color theory: “Shades sitting opposite one another on the color wheel, called complementary colors, neutralize each other,” explains Good Housekeeping Institute Beauty Lab Director Birnur Aral, Ph.D. Since purple is yellow's opposite, when you wash your hair with a purple shampoo, it lessens any appearance of yellow or orange brassiness. They can also help keep blonde strands from losing their shine.

Violet-tinged formulas “work best on blondes that prefer a more cool or neutral tone,” O’Connor says, but they're also great for light brown, silver or highlighted hair. How often should you use a purple shampoo— and can you use it every day? Our experts suggest swapping one in for your regular shampoo once every few weeks, or when you want to brighten your shade or minimize brassiness or yellowing. As for how to use a purple shampoo, for best results, allow it to sit for three to five minutes before rinsing to fully penetrate the hair.

Here, the best purple shampoos to keep your hair color looking vibrant, including drugstore, sulfate-free, and Amazon picks, and formulas for dry, brown, and gray hair.