"I'm not exaggerating when I say that I've tried countless purple shampoos and conditioners — and most have been disappointing. I find most purple shampoos to be drying, ineffective, or just plain meh. Not so, with the L'Oreal Paris Elvive Colour Protect Purple Shampoo (£3). This formula is pretty damn strong, so I use it once per week to neutralise brassiness in my platinum blonde colour, and I don't leave it to sit on my hair. A small amount goes a long way — so lather it up and rinse immediately unless you prefer a purple or grey look. Pro tip: for reasons unknown, this shampoo is half the price in supermarkets than in the drugstore (you're welcome)."