Does anyone know what would happen if I use sunsilk blondebombshell color BOOST on my dark brown hair? Would it get lighter or it would mess up my hair..

1. Where did you find the blonde color boost? Its been totally discontinued and is nowhere to be found anywhere here! When it went on closeout I bought all of it from the store I work at, and I've been rationing it carefully!

2. It will temporarily lighten your hair. I have light brown/dark blonde-red hair and I use it to bring out my natural highlights. Its like sun-in but not permanent. Also it makes your hair very soft. On days when you use it, you can use it instead of conditioner. You will see a difference but its not drastic and washes out in a few washes. Be careful to keep it out of your eyes though. It would probably give dark brown hair some reddish highlights.