There is no scientific evidence to support the use of usnic acid for weight loss. Supplements containing usnic acid are associated with severe liver toxicity.
Usnic acid is a compound found in lichens. It has been used as a preservative in moisturizing creams, and as an ingredient in toothpastes, mouthwashes, and deodorants because of its antibacterial properties. Dietary supplements that contain usnic acid are promoted for weight loss but scientific evidence is lacking. The supplements have also been associated with liver toxicity.
This claim is not supported by scientific evidence.
Usnic acid has been used in moisturizing creams, toothpastes, mouthwashes, and deodorants because of its antibacterial properties.
In one clinical study, an intravaginal formulation of usnic acid and zinc showed favorable results when used as an adjunct to radiosurgery in patients with human genital papillomavirus infection.
This claim is not backed by scientific studies.
This use is not supported by scientific evidence.
Weight loss supplements containing usnic acid are associated with severe liver toxicity.
You are taking anticoagulants: Theoretically, usnic acid may have additive effects with anticoagulant medications.
You are taking drugs that are substrates of Cytochrome P450 3A4: Animal studies suggest usnic acid can decrease the effects of such drugs. Clinical relevance is not known.
Usnic acid can cause liver damage when used in high doses.
Allergic reactions have been reported with topical use.
Usnic acid is a secondary metabolite of lichens. Some species of lichens have been used in traditional medicine for pain relief, fever, and wound healing. Usnic acid is used as a preservative in cosmetic products. It demonstrated antioxidant (1), anti-inflammatory (2), antimicrobial (3)(4), antiproliferative and anticancer (5)(6)(7)(8), and dermal burn healing (9) properties in vitro and in animal models. A clinical study using a formulation of usnic acid and zinc showed effectiveness against genital human papillomavirus infection (10).
Over-the-counter supplements that contain usnic acid have been promoted for weight loss but scientific evidence is lacking (11). Misuse of usnic acid products has been associated with severe hepatotoxicity (12)(13)(14).
Usnic acid is found in Kombucha tea (12).
Lichens are not commonly consumed as food.
Usnic acid has two enantiomers (+)-usnic acid and (-)-usnic acid which are thought to have different biological activities. Studies show that (+)-usnic acid has antimicrobial (3)(4), anti-inflammatory (2), and cytotoxic (5) effects while (-)-usnic acid exhibits anti-protozoan properties (15). Usnic acid can induce oxidative stress and inhibit mitochondrial function in liver cells (16)(17) which may contribute to its hepatotoxicity. However, conflicting data indicate that usnic acid protects gastric cells from drug-induced oxidative damage (1). It may inhibit prostaglandin synthesis (2).
Usnic acid demonstrated antiproliferative effects against breast cancer cells independent of p53 activity (6). In lung cancer cells, usnic acid inhibited cell growth involving G0/G1 phase cell cycle arrest and induced cell death via mitochondrial membrane depolarization and induction of apoptosis (18).
Weight loss supplements containing usnic acid have been associated with severe hepatotoxicity (14).
Acute hepatitis is also attributed to the use of Kombucha tea, which contains usnic acid (12).
Liver damage with use of usnic acid-containing supplements (12)(14)(19).
Topical use may cause local irritation and allergic reactions (11).
Fulminant liver failure: Following use of usnic acid for weight loss in one woman that eventually required liver transplantation (13).
Anticoagulants: Theoretically, usnic acid may have additive effects with anticoagulant medications (14). Cytochrome P450 3A4 substrates: In animal studies usnic acid induced CYP3A4, and may affect the intracellular concentration of drugs metabolized by this enzyme (20). Clinical relevance is unknown.
In 2 case reports, usnic acid dramatically increased ALT, AST, ALK P, and total bilirubin levels, and also prolonged prothrombin time (14).