As with any shampoo, you want to look for a high-quality one that is sulfate free," he says. "A good rule of thumb is that the lighter it is, the more subtle of a tone it’s going to be. The brighter the purple, the more drastic the results will be." Session stylist Ali Pirzadeh concurs and recommends using your regularconditioner afterwards."I wouldn't bother with a purple conditioner as well, as you want to make sure your hair is still being nourished." What's the difference between toner and purple shampoo? Those who bleach their hair and live in hard water areas (which creates more mineral build-up on strands), should only use it once a week. Meaning, one bottle will last you until your next colour appointment, if not longer. I decant half my purple shampoo into half a bottle of Oribe Shampoo For Moisture Control," she says. It's arguably blonde hair's biggest nemesis: brassiness. Why does it happen? "Lighter strands often struggle to look shiny and healthy," says Steve Shiel, scientific director at L’Oréal. "This is because free radicals in the colouring process break down protein so blonde hair becomes porous."

This shampoo is marketed for people with blonde, gray, and highlighted hair, and boasts a strong color-depositing formula. Indeed, multiple reviewers write about how impressed they are with it, saying that they noticed a marked improvement in their hair color after just one wash. Because it’s so highly pigmented, the brand recommends using gloves when applying this shampoo to wet hair before lathering well and rinsing as thoroughly as possible. If you find that your hair is in even more need of anti-brassy TLC, repeat the process and leave the formula on for three to five minutes before rinsing.We used the purple shampoo twice a week and found that it kept our honey blonde highlights looking creamy and cool – even two months post colour. It lathered well in the hair, smelt refreshing and didn’t feel drying once rinsed, although we’d still recommend following up with a nourishing conditioner to pamper our hair and seal the hair cuticle. Top tip: we massaged the foaming shampoo into our hair for two minutes to make sure each strand was properly coated.

Blonde hair can turn yellow with time for two reasons. The first is salon-applied toner rinsing out over time to reveal a yellow undertone. The second is the hair shaft absorbing minerals and chemicals from the environment, which can cause yellowness. Chlorine from swimming pools and even sunlight can be major culprits for introducing yellow tones to blonde hair. This is particularly true of bleached hair, which is more porous. The violet tones in purple shampoo counteract any brassy tones in the hair, giving a more silvery finish that appears brighter and more vibrant.

R+Co Sunset Blvd Daily Blonde Shampoo

What Sunil says: "A full believer in the restorative and transformative powers of Olaplex, after having recently gone blonde, I was thrilled when they launched this product. It doesn't leave my hair feeling dry - my hair ACTUALLY feels better after using - and the colour payoff is seriously impressive."

Ro Morgan is a New York-based hairstylist who specializes in natural hair, wigs, and hair extensions. Morgan works with celebrity clientele such as Naomi Campbell, LionBabe, Precious Lee, and more. NBD, right?! If you like the sound of the shampoo/conditioner combo from Bold Uniq, you can also grab the same product in an intensive mask. This one is super hydrating, so it's great for those with hair that is both dry and brassy. "Most potent toner you'll get outside a salon service," says one reviewer, adding, "I've had bleached hair for 15 years and this is hands down the strongest toner I've ever used. Lifts the colour in under a minute on my hair and being a toning mask, it doesn't leave hair feeling crispy in the way that many toning shampoos do."Come summer, bottle blondes know the importance of preserving hair color at home. This is where the best purple shampoo for your hair, whether it’s a traditional cleanser or a deep conditioning treatment, comes into the equation. “Blondes have more fun, but the fun doesn’t last long!” jokes colorist Richy Kandasamy. “Blondes have a very light palette—and delicate, clean blonde color tends to fade faster, lose shine, and can look brassy or yellow very fast.” Below, find a breakdown of how purple shampoos work to keep hair color bright and vivid, as well as how best to work them into your routine. What is a purple shampoo? We spoke to Gina Conway from Gina Conway Salons and Spas, who helped shed some light on why hair goes brassy and how a purple shampoo can help:

If you’re a keen swimmer, use a hair protector to keep chlorine from stripping your hair colour and turning it yellow or even green, and rinse hair immediately after swimming.Unfortunately, the colour fading is an unavoidable evil, but purple shampoo is a great way to keep your blonde hair looking salon fresh for longer. It works by depositing violet tones that neutralise brass for brighter tresses without the need for bleach. Purple shampoo washes in and rinses out just like any other shampoo, making it suitable for use on all hair types and textures. Hairstylist Kevin Kelly adds that purple shampoo is only really a good fit for people with light hair. "You cannot use purple shampoo on caramel highlights," he says. "It will not do anything. It’s not light enough for the color to grab on to." He also adds that purple shampoo works wonders "if your hair isn’t light enough or your hair was highlighted or colors in properly." The biggest misconception surrounding purple shampoos is that they don’t work on darker tones. This, Galvin argues, is incorrect. “Purple shampoos can be used on dark brunettes who find they have a brassy overtone,” says Galvin. “Particularly if you have had balayage and want a creamier colour rather than copper.” So more Angelina Jolie than Penélope Cruz. How to use purple shampoo Contrary to popular belief, purple shampoo doesn't actually lighten your hair. Instead, it deposits purple pigments to neutralize warm tones, making it appear brighter," says Mondo. And as much as it's possible to overuse the shampoo, temporarily giving your hair a purple hue, in other cases, "you may not see desired results until two or three uses of purple shampoo," says Morgan. Consider your hair type The best way to use a purple shampoo is on wet hair. Simply lather it up and leave on for about two to four minutes, depending on the amount of colour-correcting needed.