I applied it on previously dyed hair that had been bleached underneath, so the lower parts became very blonde and the natural hair turned orange like copper. I think it is a bit weaker than professional products you get at the hair salon, so it is ideal for natural blondes who just want to lighten a few tones, but for brunettes it will not lighten much. However, it is safer for home use because it has the exact dosages inside the box.

My hair is black. The product does not work miracles. It lightened the roots very well, but with quite a bit of burning. The rest of the hair lightened by 2 tones to a dark brown, let's say. So it only works if you have brown hair and want to lighten it to a reddish copper. Definitely blonde is a bit difficult. It leaves quite a few orange shades. P.S. I wanted to lighten it to make it red, not to become blonde.