Purify Extra-Purifying Shampoo is a silicone-free and sulfate-free purifying shampoo for very oily scalps. Although sebum is an essential feature of a healthy scalp, its overproduction can result not only in the asphyxiation of the hair follicles, but also in an unsightly, greasy appearance. With this in mind, this shampoo helps rebalance very oily scalps without disturbing their delicate balance.