As any blonde (natural or otherwise) knows: Brass is public enemy no. 1 to keeping your strands bright. This is especially top of mind during the summer months since UV exposure and chlorine from the pool can cause that dreaded orange tint to set in more quickly.
Luckily, the solution is simple. Add a purple shampoo to your regular routine to help offset those unwanted warm tones and bring your blonde (or grey) back to neutral.
How does purple shampoo work?
Well, just as its name implies, the shampoo itself has a purple tint. When applied to your hair, it deposits purple pigment onto your stands to neutralize any overly yellow or orange tones that have crept in and keep your blonde true to its intended shade.
It’s the same application of color theory that you’d use if you were color correcting blemishes or dark circles with makeup; you want to use opposite shades on the color wheel to counteract the other. And since yellow sits opposite purple on the color wheel, a purple shampoo will cancel out any warm tones, so that it’s closer to that cool, ashy hue you left the salon with.
Recently, we’ve seen a tip floating around the Wild West that we call the Internet that recommends applying purple shampoo on dry hair rather than on wet hair, as we’ve always done. Proponents of this trick claim that it increases absorption of the purple pigments, which gives you cooler, longer lasting results. Which leads us to the next question...
Can You Put Purple Shampoo on Dry Hair?
In short: No, you shouldn’t put purple shampoo on dry hair. While it’s true that dry hair will absorb more pigment, it’s also uneven in its absorption.
For most if not all of us—blonde or not—the ends tend to be drier and more porous than the rest of our hair. Ditto for any areas that were lightened with bleach. (We’re looking at you, highlights.) That said, applying purple shampoo on dry hair can result in a patchy finish.
OK, so what is the best way to use purple shampoo?
Well, for starters, you want to apply it on completely wet hair. (Note: If you have especially dry or brittle ends, we’d also recommend putting a tiny amount of conditioner on just the tips to prevent them from absorbing too much pigment.)
Most stylists we’ve spoken to recommend using a purple shampoo once a week as a starting point. If that’s not doing the trick and you’re still seeing a lot of brassiness, you can up the usage slowly to two or three times a week.
Just make sure that whenever you use it, you coat all your hair evenly, taking care to massage the shampoo into your roots and raking it through the ends. And use your purple shampoo as directed on the label. If the directions recommend that you leave it on for 3 to 5 minutes, leave it on for 3 to 5 minutes.
How do I choose the right purple shampoo?
Even for something as specific as purple shampoo, there are so many options available to us, which can be confusing when shopping. To simplify things as much as possible, a general rule of thumb is this: The lighter the shade of purple shampoo, the more subtle the effect will be.
So, if you have more of a honey blonde coloring—or have balayage or highlights—a violet-tinged shampoo will do the trick. If you have icy platinum, gray or very light blonde strands that you want to keep on the cooler side, opt for a darker purple or even indigo hued shampoo for best results.