Review (5/5): It works for colorful hair dyes!!
(Left - hair turquoise with aquamarine from Arctic Fox / right - after 1 - yes, only one - application of the product)
It really works. I have mixed 1:1 and applied in my hair. I let it for about 40 minutes with a plastic bag on, then I washed twice with shampoo. To me it didn't smell strongly bad or anything, just when I mixed the 2 bottles (after that it was a really light smell and it didn't bother me at all). Plus, my hair looks exactly the same, so no damage was made. 5 out of 5 to me, I'll definitely be using it again.