What would happen if I lightened my brunette hair with lemon juice and the sun?
It would just lighten the tone; lemon juice isn’t strong enough to bleach brown hair in one go. Do this regularly (assuming you have dark brown hair) you’ll end with medium/dark brown hair, but nothing compared to the bleaching wonder that is hydrogen peroxide. To be honest, the lemon juice thing works at its best on blondes. Don’t get into this habit; lemon juice doesn’t protect hair cuticles. You could get very thick, brittle hairs.
