I used this on bleached hair and the first time I left it on for 15 minutes and it didn't work very well. But I re-did it the next day and left it on for for almost an hour and it's AMAZING. I have it striped with blue; the only problem being that they tend to blend together, meaning that you can't always tell it's there. But I love this dye and it stays really well, it just needs to be left for longer than it says xxx