Your purple shampoo FAQs, answered:

What is purple shampoo and how does it work?

Essentially a shampoo that’s been tinted with violet or lilac pigments, purple shampoo is the ultimate at-home toning solution for neutralising any unwanted orange or yellow undertones in blonde hair.

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. So, soft purple and lilac pigments are ideal for erasing yellow tones, while more bold blue and violet pigments help counteract any warm tones and brassiness.

How do I know if I need a purple shampoo?

If your natural blonde or chemically lightened hair is starting to look a little brassy, chances are you’d benefit from a purple shampoo. Particularly common amongst bleached blondes, 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 – turning your platinum or ashy look a little too warm-toned.

But it’s something that can happen to natural blondes, too – because blonde hair is naturally quite porous. This means that it soaks everything in a lot more – including 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.

Gone for some slightly warmer-toned highlights or balayage? Purple shampoo is still great for countering excessive brassiness – but you’ll want to pick one that’s a little more subtle and gentle. “If you have warm, golden, or honey blonde hair, you might want to avoid an overly cool-toned purple shampoo,” Hamill adds.

How long should I keep 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 also don’t need to follow up with your regular shampoo – just 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 it on for too long, or opt for a formula that’s too strong.

As Hogan explains, it’s also wise to care for your highlighted hair in-between salon appointments with a mask, too – particularly during the summer months. “Alongside using your purple shampoo, using a nourishing hair mask containing a UV filter will really help you preserve your colour,” he adds. “The Oribe Beautiful Colour Mask is my personal favourite.”