5ñ-Dihydrodeoxycorticosterone (abbreviated as DHDOC), also known as 21-hydroxy-5ñ-pregnan-20-one, is an endogenous progestogen and neurosteroid. It is synthesized from the adrenal hormone deoxycorticosterone (DOC) by the enzyme 5ñ-reductase type I. DHDOC is an agonist of the progesterone receptor, as well as a positive allosteric modulator of the GABA<sub>A</sub> receptor, and is known to have anticonvulsant effects.