Estrone is a 17-oxo steroid that is estra-1,3,5(10)-triene substituted by an hydroxy group at position 3 and an oxo group at position 17. It has a role as an antineoplastic agent, an estrogen, a bone density conservation agent, a mouse metabolite and a human metabolite. It is a phenolic steroid, a 17-oxo steroid, a member of phenols and a 3-hydroxy steroid. It derives from a hydride of an estrane.