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. What causes brassy hair?

Use a dark purple shampoo if you have grey, silver, or platinum hair. Darker purple formulas, some of which verge on indigo or blue in hue, work best on platinum, gray, or light blonde hair. [11] X Expert Source Michael Van den Abbeel 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 its most vulnerable. If you're looking for a product that you can 100% rely on, this is that product."

Use a dark purple shampoo if you have grey, silver, or platinum hair. For blonde hair, go with a bright purple or violet shampoo. Moisturizing FormulaSome purple shampoos can dry your hair out, but moisturizers in this purple shampoo will keep your hair soft and shiny.

For those with damaged or dry hair, a nourishing toning mask will probably be better for your hair than a purple shampoo. When it comes to hair, there’s nothing better than fresh color. The challenge? Maintaining that just-left-the-salon level luster until your next dye job. Blondes in particular may notice signs of brassiness over time. This yellow or orange cast can be caused by a number of things, including "your color oxidizing over time, exposure to UV light, chlorine and even traces of copper in your water,” explains Meri Kate O’Connor, celebrity colorist at Loft 647 in West Hollywood, California. This is where a purple toning shampoo can help. What is purple shampoo good for and what happens when you use it? Avoid purple shampoo if you have dark hair. Purple shampoo is ideal if you want to turn blonde or silver hair from a brassy to a brighter, more neutralized color. [14] X Expert Source Michael Van den Abbeel Natural blondes are definitely in the minority worldwide, and even in the U.S. Globally, 2 percent of people are naturally blonde (or blond, going by the male spelling), and only 1 in 20 in the U.S. are. However, if you add in the 1 in 3 women who bleach their hair, the number of fair-haired people rises significantly. But even natural blondes may find they need to lighten a little, since blonde hair typically darkens over time.

Wearing suitable gloves, apply to wet hair, lather and rinse well. Repeat if necessary. For maximum benefits, leave second lather on 3-5 minutes. Follow with Total Results So Silver conditioner. AQUA / WATER , SODIUM LAURETH SULFATE , SODIUM CHLORIDE , COCO-BETAINE , GLYCOL DISTEARATE , DIMETHICONE , COCAMIDE MIPA , SODIUM BENZOATE , HEXYLENE GLYCOL , PARFUM / FRAGRANCE , SALICYLIC ACID , CARBOMER , CI 60730 / EXT. VIOLET 2 , GUAR HYDROXYPROPYLTRIMONIUM CHLORIDE , SODIUM HYDROXIDE , CITRIC ACID

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.Session stylist Ali Pirzadeh concurs and recommends using your regularconditioner 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? Say goodbye to yellow tones with SoSilver purple shampoo. Designed specifically for blonde or silver hair, the purpledyes correct unwanted yellow and brassy undertones, leaving a cool finish to your colour. Your roots need more time to absorb the shampoo than your ends, which is why you apply the shampoo there first. First, you don't want to use a purple shampoo every day. Our experts suggest swapping one in for your regular shampoo once every few weeks, or when you want to brighten your shade or minimize brassiness or yellowing. As for how to use a purple shampoo, for best results, allow it to sit for three to five minutes before rinsing to fully penetrate the hair. Use purple shampoo once a week to combat brassiness. Alternate your purple shampoo use with regular shampoo formulated for color-treated hair so your hair color stays light and even. If you have warmer naturally blonde hair, use purple shampoo only when you notice yellowing. Pay attention to your hair and use your judgment when establishing a routine. [15] X Research source

You don’t have to have dyed hair to benefit from purple shampoo. In fact, those with naturally blonde and naturally silver hair find it reduces undertones. 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.

Put simply, violet-hued shampoo is the haircare equivalent of a surly bodyguard. It protects against dullness and unwanted warm tones between colour appointments. 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." Just because you use purple shampoo, doesn’t mean you can do away with a toner. If your salon provides that service, use purple shampoo as a supplement. If you color your own hair, look for a toner that can reduce undertones.