Chemical compound resulting from the interaction of zinc with sulfuric acid. There is little research showing this to be beneficial for skin. The information that is available shows that it does not help skin healing and can irritate acne-prone skin (Sources: Dermatology Research and Practice, July 2014; and Acta Dermato-Venereologica, 1990, volume 154, Supplemental, pages 1-36) and it can be a skin irritant when used in large amounts. A small amount of zinc sulfate is sometimes used in high-strength vitamin C treatments to stabilize the vitamin C (typically seen on the ingredient list as ascorbic acid). In these instances, the zinc sulfate is unlikely to be a source of skin irritation.