Selenium sulfide is a chemical compound created by fusing atomic selenium (Se) and sulfur (S). The selenium and sulfur combination has been shown to promote skin health and thus selenium sulfide is found in many cosmetic, hair, and skin care products. It’s probably best known as an antifungal and is used to treat tinea versicolor, a fungal imbalance of the skin. Selenium sulfide helps relieve itching and flaking associated with dandruff. It may also help soothe seborrhea, or seborrheic dermatitis.