ELLE Edit: The 9 Best Purple Shampoos For Maintaining Your Blonde

It's a tale as old time. Those former sun-kissed highlights losing their perfect vanilla blonde hue mere weeks after you spent what felt like an eternity at the hairdressers, and leaving you with unwanted brassy tones and haphazard balayage.

It's less than ideal, really. Which is exactly where an anti-brass - or purple - shampoo comes in. As Harriet Muldoon, award-winning colourist at Larry King Hair, tells us, a purple shampoo is a sure-fire way to boost shine, maintain your shade and even prolong visits to the hair salon.

What is purple shampoo?

As you likely learnt in any school art class, purple is opposite yellow on the colour wheel. Simply put, this means the purple pigments in anti-brass shampoos neutralise yellow tones by balancing them out, in the same way you’d wear green pigmented colour corrector on red or rosy skin.

How does purple shampoo work?

Purple shampoos (mainly for blondes) and anti-brass formulations (for anyone with warm-toned tresses) are highly pigmented to temporarily alter the colour of your hair, dispensing blue and violet particles onto its surface.

If you don’t want to use purple shampoo because your hair is already cool-toned, Harriet suggests the High Bright Shampoo range from Redken, which uses vitamin C to target dull or dark strands (in the same way it does for your skin) instead of colour pigments.

How often should I use purple shampoo?

Harriet advises using it every other time you wash your hair. ‘If you’re washing twice a week, then swap your regular shampoo out for a purple option once a week,’ she explains. ‘Use it too often and the pigment can make hair seem darker, especially if you’re using anti-brass shampoo on hair that’s already cool toned.

‘I always say it’s a visual thing so only use it when you start to feel a little brassy. Only target the areas you feel need it and I always dilute with my Larry King A Social Life shampoo to prevent overtone.’

How do I keep bleached hair healthy?

Brassiness can be caused by sun exposure, hard water and heat styling tools. If you want to combat it, you likely need to be protecting and rejuvenating your hair too. For this, Harriet suggests reaching for a bond-building treatment.

‘Your bonds may have been compromised during the colouring process,’ she says. ‘Or it could be due to over-use of heat and general wear and tear, even if you’ve never dyed your hair.

‘As well as using soft, snag-free hair accessories rather than tatty elastics, you'll need a formulation that’s going to protect your bonds and strengthen them, injecting some keratin and vital proteins back into the strands to keep them shiny and healthy.’

Luckily for you, there are myriad bond-building treatments on the market. So, once you’ve achieved your perfect tone, you can work on fortifying your strands and keeping them silky, smooth and healthy, too.

As for the best purple shampoos to shop, according to a beauty who's tried them all? Keep scrolling...

How we test the best purple shampoo

I've been dying my hair blonde for around 20 years. My hair has oscillated between more natural, brassier blonde to ashy tones. Through my own research, I've tested the majority of new, cutting-edge and cult formulas that have arrived on shelves. My hair is naturally quite straight, but I've tested a number for different blonde hair types - I've considered everything from affordability to ease of use, sustainability and natural ingredients list, and the products that limit the trips to the hair salon and in-between appointments.

The best purple shampoos, according to a beauty editor