I've always bleached/dyed my hair myself and always been aware of the risks involved with home hair bleaching... so I was pretty prepared for my hair to turn from black to a horrible reddish orange or have streaks etc etc, but I had also bought a hiar dye to dye over the top, as suggested on the packet. I hadnt bleached my hair in over a year and I thought it best to do a strand test beforehand, and i'm glad I did. THE PRODUCT DID NOTHING! I had blonde and red hair prior to dying it black, and i've re-touched my roots with black hairdye for the last year and a half. This haircolour remover clearly states it will remove any colour, irrelevant of when the hair was dyed. I left the strand test for an hour and 2 minutes and nothing, not even a shae lighter. I'm not a professional, but I have bleached my hair probably 30+ times in my life and for the price of the product, it should have done more.