Here's how to stop your blonde hair going yellow

What is it?

Purple shampoo contains semi-permanent purple dye, designed to keep blonde hair (particularly colour-treated) looking fresh and bright, as well as eliminating yellow tones from naturally silver or white hair.

How does it work?

Through colour correction. Chemically lightened and naturally blonde or silver hair can look yellowy, due to mineral deposits from hard water, damage caused by UV light and heated styling tools, a build-up of old colour or styling products, or your hair’s natural warmth coming through. Cool purple tones (think violet and indigo) are opposite to yellow and orange on the colour wheel, so counteract brassiness. They also help restore lost shine, as cooler colours reflect more light than warmer ones.

Who needs it?

Anyone struggling to keep naturally blonde or chemically lifted hair looking clean and bright, though brunettes can also use it to brighten highlights. It’s also great for grey hair that has developed a yellowish tinge, for which it’s occasionally called silver shampoo.

What else do I need to know?

It can be drying, though new formulations are enriched with high-spec hydrators, such as hyaluronic acid. Using damage-repair or colour-safe ranges and conditioning treatments between purple washes should keep dryness at bay.

How do I use it?

Carefully. Overuse can leave hair looking dark or dull, while fi ne hair and more processed areas can grab onto extra pigment – creating stains. Use it once a week if you wash your hair every day, or less often if you wash it less frequently. If the bottle suggests a window of leave-in time, start at the shorter end the first time you use it. If your hair becomes too lilac, use it less regularly or mix it into your usual shampoo. And, as the tips and ends of chemically coloured hair tend to be the lightest, you may only need to apply it through the roots and mid-lengths and let the lather reach the tips as you rinse.

What about purple conditioners?

Because conditioner doesn’t lift the cuticle of the hair in the way shampoo does, pigments sit on the outside of the hair, rather than penetrating, meaning the effect only lasts until your next wash.

What if it goes wrong?

If a few washes with regular shampoo don’t remove all traces of purple, try a clarifying or detox shampoo, such as O&M Original Detox Shampoo ($32.95, adorebeauty.com.au) or an anti-dandruff formula like Head & Shoulders Supreme 0% Purify & Volume Shampoo ($14.99, Priceline). Use it three or four times and then follow with a conditioning hair treatment.

Our Beauty Editor's Picks:

1. Hask Blue Chamomile & Argan Oil Blonde Care Shampoo, $9, Kmart Brightens the blonde, while taming frizz.

2. John Frieda Violet Crush Intense Purple Shampoo, $17.99, Chemist Warehouse A cooler blonde after just one wash.

3. Glow Lab Purple Shampoo, $18, Woolworths Neutralises yellow and enriches hair with keratin and vitamins.

4. Schwarzkopf Extra Care Blonde Purple Shampoo,  $12.99, Chemist Warehouse Banishes brassiness and strengthens hair with ease.

5. Eleven Australia Keep My Hair Blonde Shampoo, $25.95, adorebeauty. com.au Counteracts yellow tones while both strengthening and nourishing.