Sulfates are added to shampoo for a reason—they help de-grease strands, dissolve oil, and give the formula that frothy, foamy quality. But because they work by scrubbing away the body's natural oils, sulfates may also dry strands, irritate the scalp, and, in extreme cases, cause damage to the cuticle (the hair's outer layer). in these situations, a sulfate free formula is most definitely the best for your hair.