Epiandrosterone, or isoandrosterone,also known as 3β-androsterone, 3β-hydroxy-5α-androstan-17-one, or 5α-androstan-3β-ol-17-one, is a steroid hormone with weak androgenic activity. It is a natural metabolite of dehydroepiandrosterone (DHEA) via the 5α-reductase enzyme. It was first isolated in 1931, by Adolf Friedrich Johann Butenandt and Kurt Tscherning. They distilled over 17,000 litres of male urine, from which they got 50 milligrams of crystalline androsterone (most likely mixed isomers), which was sufficient to find that the chemical formula was very similar to estrone.
Epiandrosterone has been shown to naturally occur in most mammals including pigs.
Epiandrosterone is naturally produced by the enzyme 5α-reductase from the adrenal hormone DHEA.
Epiandrosterone can also be converted from the natural steroidsandrostanediol via 17β-hydroxysteroid dehydrogenase or from androstanedione via 3β-hydroxysteroid dehydrogenase.