Brassiness is when unwanted warm tones (such as butter yellows, reds and oranges) start emerging from strands that were previously a perfect shade of platinum, ash brown or cool blonde. While it tends to affect some hair colours more noticeably (that’s you, bleached blondes), it can happen whether you’re naturally blonde, you’ve dyed your dark hair a lighter colour or you’ve treated yourself to some highlights or balayage. Just note that according to Hamill, “if you have warm, golden or honey blonde hair, you might want to avoid cool toned shampoos.” Essentially, think about the result you are looking for before reaching for the stuff.
Brassiness often happens in hair that’s been lifted several shades lighter, as the melanin from your hair’s naturally deeper tone starts to creep back through. Because blonde hair is naturally quite porous, even those born with it can notice a change. Blonde hair tends to soak everything in a lot more, which includes build-up from chemicals like chlorine, minerals from hard water, pollution in the air and even UV rays from daylight – all of which can bring out brass tints.
How does purple shampoo work?
Purple toning shampoos rely on a little genius concept called ‘colour theory.’ Imagine if you joined the two ends of the rainbow together to form a colour wheel. The colours that sit opposite each other can effectively cancel each other out and neutralise them.
For example, orange offsets blue undertones (it’s why you get salmon coloured concealers to cover the blue tint of your under-eye bags). Purple and lilac erase yellow and orange tones, which is why the best hair products for countering brassy tones in blonde hair, grey hair and white hair.
How long should I leave purple shampoo in my hair?
Generally, it’s recommended to lather on your purple shampoo and leave it to work its magic for a matter of minutes, depending on how much toning you’re after. Every formula is different, and you must check the instructions on each tube first. It also depends on your blonde, says Hamill: “For white and bright natural blonde, I’d suggest just washing the shampoo in and out of your hair like any other shampoo, but for silver and grey tones you could leave it in a little longer.” You don’t need to follow up with your regular shampoo. Afterwards, rinse it out and follow with your favourite conditioner as usual.
As mentioned, it’s important not to overuse your shampoo either. Once a week should be fine, or less if you start noticing dull hair. But be warned: “If you have a clean white blonde colour, the pigment could literally turn it blue,” says Hamill – particularly if you overuse, leave on for too long, or opt for a formula that’s too strong.
As Hogan explains, it’s wise to care for your highlighted hair in-between salon appointments with a mask, too, especially in the hotter months when they’re exposed to the sun: “Alongside a purple shampoo, it’s also important to care for your summer colour with a nourishing mask containing a UV filter – Oribe Beautiful Colour Mask is my personal favourite.”
After more haircare content? Head this way for the best shampoos for all hair types and over here for conditioners to pair with them. Elsewhere, we’ve got purple shampoo, the best shampoo for fine hair, the best shampoo for coloured hair and the best shampoo for frizzy hair. Head this way for soothing shampoo for sensitive scalps, the best shampoo for curly hair and the best shampoo for greasy hair.
For more makeup, skincare, haircare and wellness content from our Commerce Writer Denise Primbet, follow her on Twitter @deniseprimbet and Instagram @deniseprimbet.