Usnea extract, also called usnic acid or old man’s beard, is a medicinal substance known as lichen — a species mixture composed of a fungus and an algae. Traditionally, usnea was used to aid in digestion and treat common infections. However, additional research is needed to support these purported health benefits of usnea extract. Before you use this supplement, talk with your doctor about the harmful side effects and risks associated with usnea extract.
Using usnea extract may damage your liver. Symptoms associated with liver damage include abdominal pain, jaundice, dark urine, pale or light-colored stools, bloody stools, swelling or confusion. Left untreated or undetected, liver damage may become permanent. Seek prompt care from your physician if you develop any liver damage symptoms while taking usnea extract.
Topical applications of usnea extract may cause severe skin irritation or an allergic reaction. The treated skin region may appear inflamed and may be itchy, dry or tender to the touch. A severe allergy to usnea extract may induce life-threatening health complications, including shortness of breath, difficulty swallowing, hives, facial swelling and loss of consciousness. Anyone who develops a severe allergic reaction after taking usnea extract should be seen by an emergency medical provider immediately.