I have used this for years. Currently lightening my hair gradually from a base 3-4 to blonde by doing highlights. I'm base 5-6 with some grey and have been using 3% (10vol) wella peroxide on the roots and 9% (30vol) on coloured ends in foils. So far it's lightening pretty evenly and I've been using an ash toner and purple shampoo and conditioner plus a weekly intensive mask. The bleach is mild enough to lighten and tone without causing too much damage if you know your hair well and use it properly