Just used this to strip and lighten my hair in preparation for dying it red; I had used so much black dye in my hair that my natural hair color had darkened, my roots were many shades darker than before I started dying.
It's bleach, it does what bleach says, and as long as you follow the directions you should be fine....do NOT put it on your roots before your ends. Common sense, but even I fudged that up a bit, and I've been bleach blond before.
Smells terrible, use in a well ventilated area, but it does what it says it does for less than ten bucks, so who's complaining?
I'm naturally dirty blonde but usually use L'Oreal preference to dye it more of a Playboy blonde color. With Superior Preference, if it's left on too short=orange, too long=purple/grayish hue for a few days with usually no middle ground which I've come to accept.
This stuff is BLEACH. I didn't know that when I purchased it, but where it's located, with the other bleach products....totally a derrrrrrp moment. Anyway, it colors (strips?) hair without leaving any weird hue or brass behind which is awesome. The conditioner is purple but not as strong as Clairol Shimmer lights or Ion's version, so if it does turn brassy---it's not going to do anything spectacular.
Just have to remember, this is bleach! If you put it on your whole head for the max amount of time, don't complain that it fried your hair...common sense.
I will definitely repurchase since this is the best drugstore brand I've found to get that bombshell blonde without having a grey hue for a few days.