I've been around for about 15 years dyed hair. My Natural Color is a bright maroon.
The product I have applied to my dyed black hair. I have very thin and vulnerable hair. So I've been thinking for so long. But worse than the color and the (earlier still) ammonia, it could not be so.
I have kept myself peniebel exactly to the instructions and beautiful shower for 30 minutes and rinsed. It's really really simple girls, if you just jump into the shower, then you do not get as neck pain :-)
With the result I am more than satisfied. The black is removed completely and my hair is almost back to normal, a bit darker. Another color or tint I have not used, because the result has been to me so much.
The product report something like rotten eggs, but it has its limits. My hair has the smell unfortunately long stored (4 days) but now it's all out.
I would do it again at any time.