Pregnenolone is a 20-oxo steroid that is pregn-5-ene substituted by a beta-hydroxy group at position 3 and an oxo group at position 20. It has a role as a mouse metabolite and a human metabolite. It is a 3beta-hydroxy-Delta(5)-steroid, a 20-oxo steroid and a C21-steroid. It derives from a hydride of a pregnane. Pregnenolone is an endogenous steroid hormone for inhibition of M1 receptor and M3 receptor-mediated currents with IC50 of 11.4 μM and 6.0 μM, respectively. Pregnenolone has memory-enhancing effects, used in the treatment of fatigue, Alzheimer’s disease, trauma and injuries.