I went through a bright blonde phase. It’s a rite of passage, right? But I grew up in a super small town in the U.S. where we had well water, and it destroyed my blonde. Within a wash, the hard water could take my icy colour to full-on yellow. That’s when I was first introduced to purple shampoo. We had a good run for a few years there, but now that I’m not blonde, I assumed I’d never need to lather up with one of those bright, hand-staining shampoos again. I was wrong!
K18, the brand that makes some of my favourite hair products (including their mask and the best dry shampoo to ever exist), just unveiled their newest innovation: the TripleBright Oxidation Defense Purple Shampoo Foam. And according to celebrity hair colourist Rachel Bodt — she’s worked with Beyoncé, Lorde, Ariana Grande, Barbie Ferreira, and more; casual! — this purple shampoo proves it’s good for every single hair colour from blondes to greys and reds.
About the shampoo:
In true K18 fashion, they couldn’t just make a normal purple shampoo, of course. “This shampoo is different from your traditional purple shampoo that just deposits colour to counteract yellow tones,” Bodt tells me. “With other purple shampoos, it just deposits so it can leave the all-over colour looking really muddy and a lot darker than where you started,” she explains. But with K18, it actually “clarifies hair, removing metal and mineral buildup in the hair and preventing further oxidation.” It does this using a combination of chelating ingredients, which bind to metal ions and minerals in your hair that can make colour appear dull and brassy as well as dry and brittle, which is why it works for greys too as it removes yellowing and where grey hair is more brittle that pigmented hair, the chelating helps keep further dryness at bay.
The other biggest difference is the consistency: a foam. You don’t have to rub this between your palms to build up a lather. When you pump the formula into your hand, it’s already a foam, which Bodt says helps make sure you get an even tone throughout when you apply the product to your head. “I think we are all guilty of using a very pigmented purple shampoo, and it turns out splotchy or super pigmented in areas of your hair,” she says. (It’s me, hi, I have this problem often.)
So, wait, can you use purple shampoo on more than just blondes?
Yup, according to Bodt. For my red hair, Bodt used this foam to make my red a bit less vibrant so it leaned more toward a strawberry shade. Since my colour appointment, I’ve used it once to make my colour appear brighter and more even. “You can also use it on brunettes to cut any unwanted brassy tones,” Bodt says.
She only recommends using this once or twice a month, “because it’s pigmented and clarifies this isn’t something you want to use every day.” It all depends on the look you’re going for — because I’m a redhead who only wants to brighten, once a month is pretty good for me. But if I wanted to take down a brassy tone, I’d implement a bit more. “Too much ash can make the hair feel too muted and not as vibrant,” Bodt adds.
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My review:
Why is no one else doing a foam shampoo? This is such a joyous experience in the shower, I’m bummed I can only use it every so often. The immediate lather is so satisfying and definitely makes me feel like I’m getting my whole head — something I wouldn’t care about as much with a traditional shampoo, but for a product that’s impacting my colour, I want it to touch from root to tip. But this also doesn’t make my ends feel like straw either. The formula’s mix of chelating ingredients to help remove minerals and hard water, and lightly hydrating conditioners make my hair feel clean as heck but not stripped either.
Both times I’ve tested it, I’ve immediately followed with the K18 Hair Mask, and this definitely helps keep my hair feeling soft and moisturised. But I think a standard conditioner could work too, since the shampoo itself isn’t too drying.
Immediately, I noticed how much brighter my hair looks. I have red hair! You wouldn’t expect a shampoo that’s meant to eliminate brass to somehow… make my hair colour look better? But here, it works. It helps soften the tone and eliminate any harshness. It’s like my color went through a full rejuvenation sesh. My hair also still looks healthy, even after a full dye job only a few weeks ago.
Is it worth the hype?
Just like everything I’ve ever tested from K18 (I’m a fangirl, what can I say), this purple shampoo is totally worth it. Although it’s expensive, I only use a little bit once or twice a month, so one bottle will last me a very long time. It makes my colour — a strawberry blonde/copper red—look so much more vibrant and even, and I bet it’d do similar things for brunettes and blondes. Hell, if I had this as a teenager, I probably would still be blonde right now.
K18 TripleBright oxidation defense purple shampoo will be available from 27 April in UK retailers
Meet the expert:
Rachel Bodt is a celebrity hairstylist and owner of Homecoming Salon in New York, NY.
Why trust Cosmopolitan?
Beth Gillette is the beauty editor at Cosmopolitan US with more than seven years of experience researching, writing, and editing hair stories.
Beth Gillette is the beauty editor at Cosmopolitan, where she covers skincare, makeup, hair, nails, and more across digital and print. She can generally be found in bright eyeshadow furiously typing her latest feature or hemming and hawing about a new product you "have to try." Prior to Cosmopolitan, she wrote and edited beauty content as an Editor at The Everygirl for four years. Follow her on Instagram for makeup selfies and a new hair 'do every few months.
