A purple toning shampoo is well - known to the women who have been blondes for a very long time. It’s doesn’t matter if you have a cool icy tone or a warm one like Blake Lively has, this ultimate product is a survivor when it comes to eliminating yellow unwanted tones that may appear on your hair between salon visits.

How does it work? Everything depends on the colour wheel principle: purple color is opposite to yellow. This trick is widely used by make-up artists. It is called colour correction, for example, the red pimple is perfectly camouflaged by green concealer, purple under eye shadows - by the yellow one, etc. This way the purple pigment eliminates yellowish tones. It perfectly works both on cool and warm blondes.

'A purple shampoo greatly neutralizes the unwanted yellow shades even on natural hair,' explains Christel Lundqvist, founder and director of STIL Salon in Notting Hill. 

'The shampoo effect works best on light blonde colors because its easier to see cooler highlights on lighter hair color. However, you can still use the purple shampoo on some darker shades, but the produced effect won’t be very strong as we can see it on some lighter shades.'