Usnic acid is extracted from Usnea, Usnea, also known as old man¡¯s beard, which is not a plant but a lichen¡ªa symbiotic relationship between an algae and a fungus. Usnic Acid is used in powders and ointments for the treatment of infections of the skin. In cosmetic products, usnic acid is used as a preservative because it is demonstrated to have antioxidant , anti-inflammatory, antimicrobial, and cytotoxic properties in vitro. As a pure substance, in additon, usnic acid has been formulated in creams, toothpaste, mouthwash, deodorants and sunscreen products, and in some cases as an active principle. In recent years, usnic acid and its salt form, sodium usniate, have been marketed in the US as an ingredient in dietary supplement products, mostly with claims as weight-loss aides, though some as antimicrobial agents.