Ah, blonde hair. It conjures up the nostalgia of Sun-In, the sexiness of Brigitte Bardot and makes us wish we all could be California girls. Except when brassy tones creep in and ruin the sun-lifted effect. There’s no need to lose your cool (pardon the pun), though, as that’s when the best purple shampoo swoops in with its impressive hue-restoring powers.
If you’re new to this kind of shampoo, you’re in luck – we’ve spoken to some of the industry’s biggest hair experts to explain exactly how it works and how to use it. Keep reading for everything you need to know…
What causes brassy hair?
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 porousness means bleached hair soaks up unwanted minerals and metals in your tap water and acquires a yellow tinge over time. ‘It also means that blonde hair absorbs light instead of reflecting it and is more prone to damage,’ adds Shiel.
What is purple shampoo?
Put simply, violet-hued shampoo is the haircare equivalent of a surly bodyguard. It protects against dullness and unwanted warm tones between colour appointments.
‘Purple shampoo neutralises the yellow in blonde hair, leaving a creamy to ash result,’ explains leading colourist and celebrity favourite, Josh Wood. ‘This is because yellow and purple sit opposite each other on the colour wheel.’
So when you wash with this particular shade of shampoo, it deposits purple pigment into blonde hair, to counteract any yellowy tones that start to shine through.
How to use purple shampoo
This may seem obvious, but a violet-based shampoo is not made for your daily lather.
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.
But Zoe Irwin, creative director at John Frieda Salons, advises clients to be careful as purple-based products can be drying.
‘I decant half my purple shampoo into half a bottle of Oribe Shampoo For Moisture Control (£45 | Cult Beauty),’ she says.
‘The effect is softer, both in terms of the colour and how my hair feels afterwards. I wouldn’t recommend taking your purple shampoo right down to the ends. The hair there can be up to four years old so will grab onto too much of the purple pigment.
‘If you can’t avoid it, coat the ends in conditioner first to create a hydrating base and to dilute the shampoo. Then apply your purple shampoo in an ‘s’ shape on mid-lengths and work it in with your fingers to deposit the pigment evenly.’
For how long should you leave purple shampoo in?
It all depends on the instructions on the specific bottle, but not overdoing it is key. ‘If you leave a purple shampoo on for too long, your hair will have a blue-purple tinge to it,’ Irwin cautions.
Session stylist Ali Pirzadeh concurs and recommends using your regular conditioner 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?
Toners cool down or warm up your colour in between salon appointments.
An at-home version is the equivalent of a semi-permanent colour treatment mask. Free from peroxide or ammonia, it won’t actually lift your colour, but it penetrates the hair cuticle and deposits a small amount of lilac colour. This brightens old hair dye and boosts its undertones as well as preventing fade and ramping up the shine.

L’Oréal Paris Elvive Colour Protect Purple Reviving Oil, £12.99 | Feelunique
This is the first-ever brass-banishing oil. Designed to be used in-between hair washes, it should be used on clean towel-dried hair. Work 2/3 drops into dry and brittle ends for instant toning, as well as hydration.
Below are our picks for the best purple shampoo for blonde hair. Our Senior Beauty Editor, Katie Thomas, has handpicked these after testing each one personally. She has blonde hair and loves it to have an ashy tone. Any that she wasn’t keen on, just didn’t make the list. The things that she particularly focused on were: how her hair felt afterwards – did it feel dry at all or soft to the touch, and how well it took down brassiness.
Here are her recommendations for the best purple shampoos…

Olaplex No 4P Blonde Enhancer Toning Shampoo, £26 | Cult Beauty
What Katie says:
"This is the product I never knew I needed. The Olaplex system is the ultimate product range for protecting and caring for bleached hair. So the idea of a toning shampoo with the Olaplex technology inside is mind blowingly exciting. It has become a must-have for me, as I use it alongside the rest of the range. I particularly like to use it straight after I've had my colour done, when my hair is at it's most vulnerable. If you're looking for a product that you can 100% rely on, this is that product."

Fudge Professional Clean Blonde Shampoo, £14 | Lookfantastic
What Katie says:
"This was actually one of the first purple shampoos I ever used and I always find myself going back to it when I want that really icey tone to my hair. It uses ultra violet pigments to neutralise yellow tones and works brilliantly on balayage, highlights, full-on bleach and grey-blondes."

Kérastase Blond Absolu Bain Lumière Illuminating Shampoo, £22.40 | Lookfantastic
What Katie says:
"When this first came out, it was truly revolutionary. Kérastase know that dyed blonde hair causes damage, they also know that so many of us use purple shampoos to tone. Which can further dry the hair. So they created this clever formula that uses skincare ingredients such as hydrating hyaluronic acid and brightening edelweiss flower to dive deep into weaker follicles. Doesn't give you that super ashy look, but will take down brassiness."

Shu Uemura Art of Hair Yubi Blonde Glow Revealing Shampoo, £29.95 | Lookfantastic
What Katie says:
"After using this purple shampoo, my hair is at its most shiny. It's packed with nourishing ingredients, like glycerin, which counteracts dryness with a generous dose of moisture. Plus it's a really gentle formula that lifts away dirt and grime to create a bright, healthy-looking mane. There's also salicylic acid inside that exfoliates, helping to capture hair-dulling product build-up from the scalp."

Pureology Strength Cure Blonde Shampoo, £21 | Feelunique
What Katie says:
"If you're looking for a vegan purple shampoo, then say hello to Pureology. It's 100% vegan. Not only does this shampoo corrects yellowness, it also prolongs colour with an anti-fade formula and improves the strength of fragile bleached strands thanks to repairing ceramides and astaxanthin (a powerful nature-derived antioxidant)."

Redken Blondage Color Extend Shampoo, £19.50 | Lookfantastic
What Katie says:
"Redken are known for being colour experts, as well as a brand that pushed the boundaries of traditional colour. So it came as no surprise to me that this would be a punchy formula. If you used it every day (which I wouldn't recommend) I reckon you would be almost silver within the month. It eliminates brassy undertones from the first wash and contains proteins to protect against breakage. Think a brighter blonde with salon-worthy shine."

John Frieda Violet Crush Intensive Purple Shampoo, £7.99 | Boots
What Katie says:
"The brand claims that you'll see results in one wash and they weren't wrong. Hello, icy blonde hair. A really, really good shampoo at a really affordable price. Be sure to wash your hands thoroughly afterwards."

Aveda Blue Malva Shampoo, £49.50 | Lookfantastic
What Katie says:
"Before you have a go at me for the price, the bottle is 1000ml. It lasts me months and months and months. A few weeks after a colour appointment, hair can start looking dull. This isn't the strongest of purple formulas - but that's actually the beauty of the product. No harsh ingredients lift your colour so you avoid damaging it in the long run. Aveda have just been awarded the Leaping Bunny certification for cruelty-free and they're 100% vegan."

Lush Daddy-O Purple Shampoo, from £8 | Lush
What Katie says:
"This is a really fresh and uplifting choice. Which is probably down to the lemon in the formula. It's a great clarifying product and kind on your wallet, too."

Sachajuan Silver Shampoo, £25 | Lookfantastic
What Katie says:
"So Silver Shampoos work in the same way as your regular purple shampoo by neutralising brassiness, but it also adds silvery, ashy tones for the perfect peroxide blonde. An absolute must-buy if you're all about the bleached look. My Granny loves this one too, as it bring out the shine in her grey."

Bleach London Silver Shampoo, £7.50 | Cult Beauty
What Katie says:
"If you're looking for help with your colour, there really is no other place to turn to than Bleach London. I have had balayage and highlights at Bleach and let me tell you, my blonde never looked better. This super affordable shampoo brightens silver tones and keeps the lightest blonde shades 'ice ice baby'."

Matrix Total Results Unbreak My Blonde Strengthening Shampoo, £9.75 | Amazon
What Katie says:
"This shampoo is infused with citric acid, which cleanses the hair really gently. Bleaching hair damages the strand, but this formula seals the cuticle to prevent further everyday damage. Hair is left looking and feeling softer and more manageable."

Pantene Hair Biology Silver & Glowing Purple Shampoo, £5.99 | Superdrug
What Katie says:
"This shampoo brings out the best in grey, white or blonde hair. As well as removing those unwanted brassy tones, Pantene’s purple shampoo also works to soften strands for grey hair that glows."