Urolithin A is a metabolite of ellagic acid. It is produced by the body after you ingest compounds found in particularly high concentration in pomegranates (particularly the bitter components such as the skin and seeds) and can help recycle defective mitochondria. Since it is a metabolite that results from the transformation of the tannins in pomegranate by gut bacteria, it can be classified as a postbiotic.It has been demonstrated to stimulate mitophagy and improve muscle health in old animals and in preclinical models of aging.