Anyone who dyes their hair often will know what when you bleach your hair, no matter what shade it is, it will not work on the first go around. I was going from XXL Black to blonde, I've seen some people on here that are complaining because the dye made them go ginger. Well, yeah? That's what you're going to get. No hair bleach that won't completely destroy your hair is going to give you the result you want first time around.
This product however was excellent, I had to do it twice to achieve the brightness I wanted, but still only used on packet (I was dying the front of my fringe blonde so that I could then change the colour of my fringe whilst keeping the rest of my hair black.) It did what I wanted, I knew it wouldn't work perfectly and I never expected it to. Very happy, relatively cheap for straight up hair bleach. Would buy it again without hesitation.
OH and another note, it hasn't killed my hair, I let it live in conditioner for about half an hour after I'd done it (which is advised anyway) and it was fine, no damage done.