Love this shampoo - it smells great and it gets rid of those brassy/yellow tones than come with bleached blonde hair. I use it once a week and pat it onto my hair (not a lather - I find it doesn’t work as well) and I leave it on for about 10 minutes. It works amazingly well and my hair isn’t stained purple either. I use a hair mask after it - I find it can dry my hair out slightly if I use it too often.
Another plus is it doesn’t stain your bath/shower when you use it.