Purple shampoo: how to use it right without overdoing it

Purple shampoo does help with brassiness, but only with a light yellow cast and only for a while. Violet pigment neutralises yellow, so blonde looks cleaner after washing. It won't remove an orange base, it doesn't replace toning, and used too often it can dry the hair out and leave the ends lilac.

How violet pigment works

Yellow and violet sit opposite each other on the colour wheel. Mixed in the right proportion they cancel each other out, and the eye sees a more neutral, lighter tone. Purple shampoo contains a small amount of direct pigment that settles on the surface of the hair while you wash. It doesn't penetrate deeply or interact with the hair's own pigment, so the effect lasts until a few washes later.

It works best on lightened hair with a subtle yellow cast, straw or lemon, once the toner has started to fade. So I treat purple shampoo for blondes as support between toning appointments, not as a way of getting a cool blonde on its own.

How often to use it and how long to leave it on

There's no universal routine, because shampoos vary a lot in how pigmented they are. Usually it's enough to use it every few washes, with an ordinary gentle shampoo the rest of the time. Start with a short contact time: apply, lather, and rinse after roughly a minute or two. If the yellow is still there, leave it a little longer next time.

One more tip you don't often hear: apply purple shampoo first where the yellow is strongest, and to areas that are already cool or very porous last. The roots near the scalp usually go yellow less than the lengths. Apply it to well towel-dried damp hair rather than dripping wet hair, so the pigment spreads more evenly and isn't diluted. After rinsing, check your hair in daylight, not in the bathroom under a warm bulb. Artificial light often hides both yellow and lilac tones, so judging it in the bathroom can mislead you.

Why do the ends sometimes turn lilac? Lightened hair is porous, especially the ends, which have been through the most lightening and the most sun. A porous cuticle soaks up pigment more than a dense one. So with the same contact time the roots and mid-lengths look neutral while the ends come out greyish-lilac.

That's nothing to worry about and usually washes out in a few washes with normal shampoo. But if it happens every time, it's a signal: you're leaving it on too long, or the hair is very porous and needs reconstruction. Grey hair behaves similarly. Purple shampoo for grey hair takes out the yellowish tinge, but on porous grey strands it can also leave a violet cast, so go carefully and keep the contact time minimal.

Purple won't fix orange

If the hair is coppery, ginger or orange, purple shampoo won't help. Orange is neutralised with blue pigment, and blue shampoos exist for this, but even they only tone it down slightly. In reality an orange base means the hair is under-lightened, and that's a question for lightening, not aftercare. I go into the difference between yellow and orange in brassy yellow after bleaching.

Alternate it with moisturising care

Many purple shampoos are fairly clarifying so the pigment takes better, which means with frequent use the hair can become drier and coarser. For lightened hair that has already lost some of its lipids, you'll feel it. So:

• always follow purple shampoo with conditioner or a mask;
• on the days in between, use a gentle moisturising shampoo;
• if the hair starts to feel like straw, take a break for a few weeks.

Better still is a purple mask instead of a shampoo: it dries the hair less and gives you more control over the intensity. There's more on a home routine in caring for blonde hair.

What purple shampoo can't replace

It doesn't replace toning. A salon toner doesn't just neutralise yellow, it gives a specific tone, beige, pearl or cool, plus shine and density. Shampoo only slightly maintains what's already there. If you have to leave it on longer and longer to see any effect, that's a sign the toner has almost gone and the base underneath has warmed up. Extending the contact time won't solve that.

And it doesn't replace chelation. If the yellow comes from iron or other metals in the water, violet pigment only masks it while the metals stay on the hair and keep turning it yellow. Chelation removes them, and I include it in every service.

When it's time to come in

If purple shampoo is no longer keeping up, or you find yourself using it every wash, it's time to refresh your toning. My toning always comes with chelation and reconstruction; that service costs from 700 UAH. Message me on Telegram with a photo of your hair in daylight and the name of the shampoo you use. I'll tell you whether it's worth keeping and how often to use it in your case.