Now, that's not to say that sulfates are bad. "Not everyone needs to use shampoos without them," celebrity stylist Derek Yuen tells us. "Sulfates work to dissolve oils and clean the strands. If you have very oily hair, then a regular shampoo is fine for you." But for chemically-processed hair (including those with keratin treatments, color, perms, and relaxers), sulfates can actually reverse the results of those treatments.