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You leave the salon loving your bright, blonde highlights, only to look in the mirror a few weeks later and wonder where that yellow or brassy tint came from. The same frustrating shift can happen as white or gray hair begins to lose its crisp, silvery tone.
If either situation feels familiar to you, purple shampoo may be the answer you’re looking for. Used correctly, it can tone down these unwanted changes and bring back a fresher, cooler appearance without having to change your hair color. It’s also possible to have too much of a good thing, as overusing the product can leave your strands dry, dull or even faintly lavender.
Here’s how purple shampoo works, whether it’s right for your hair and how to use it without going overboard.
What is purple shampoo? What does purple shampoo do?
Purple shampoo is a cleansing product made with violet pigments that temporarily neutralize unwanted yellow or brassy tones in light-colored hair. Dr. Debra Jaliman, a board-certified dermatologist practicing in New York City, explains the idea comes from basic color theory as purple sits opposite yellow on the color wheel, so violet pigment can visually counteract yellow tones when deposited on the hair.
Because of this, “purple shampoos can provide both cleaning and temporary color correction,” Jaliman explains. She’s quick to add that “the pigment doesn’t actually permanently alter your hair color, but lightly coats it and washes out over time.”
This makes purple shampoo different from bleach, permanent dye and professional toner as bleach removes pigment to lighten the hair, permanent dye produces a longer-lasting change in its color and professional toner deposits color to refine a shade or neutralize unwanted tones.
Believing that purple shampoo can lighten or permanently recolor hair these ways is a “common myth,” says Dr. Shari Lipner, an associate professor of clinical dermatology at Weill Cornell Medical Center. “It’s also a myth that it repairs damaged hair,” she adds.
Who uses purple shampoo?
That doesn’t mean purple shampoo doesn’t have its place. The tinted shampoo is primarily intended for people with blonde, platinum, gray, silver or white hair that has developed yellow tones. “These hair colors can develop yellow or brassy tones from sun exposure, hard water, heat styling, environmental pollutants and natural oxidation that occurs over time,” explains Jaliman. At the same time, Lipner adds that purple shampoo “may not be helpful for people with darker hair unless they have some lighter sections of hair.”
Purple shampoo is also popular among people with salon highlights because yellowing can become more noticeable as salon toner fades and the hair is exposed to sunlight, heat, hard-water minerals, pollution or product buildup. But Jaliman cautions that purple shampoo is designed specifically to counteract yellow tones alone and that hair that appears more orange than yellow may respond better to a blue-toned product or professional color correction.
How to use purple shampoo
To use purple shampoo, Lipner recommends wetting your hair before working a modest amount through the scalp and lightened sections. Then, leave it on for the amount of time specified on the label – usually only a few minutes – before rinsing it thoroughly.
Leaving the product on longer will not lighten your hair, Lipner cautions. Instead, she says that doing so will give the violet pigment more time to deposit, increasing the chance that pale or porous areas will look lavender, patchy or dull.
Jaliman says that purple shampoo should only supplement and not replace regular shampoo. Lipner agrees and recommends using it “only once or twice per week, rather than using it daily.”
At the same time, ideal frequency depends on your hair’s color and porosity, the product’s strength and the degree of brassiness, Jaliman notes. “It is generally best to start with once-weekly use and adjust based on the results,” she advises. Because some formulas can be drying, she also recommends following with a conditioner formulated for color-treated hair. And she advises to stop using the product if it causes persistent itching, redness, burning or excessive dryness.
Jaliman says purple shampoo is a maintenance product for certain hair colors and not something that permanently changes color or should replace regular shampoo. When used as directed, she says, “it can help maintain or enhance the appearance of hair that has already been lightened or naturally lacks pigment.”