Wow this is super effective. I have bleach blonde hair and this takes the yellow/brassiness right out of it. Works so well that sometimes when I leave it on for a little too long you can see strands of purple throughout my hair but I really don’t mind its nice. Also need to wear gloves as it will stain your hands purple! The smallest amount goes a long way. I bought mine over 2 years ago and it still has quite a lot left (my hair is thick and long, down to my waist) and I use it about every second to third wash.