Title: Epiandrosterone
CAS Registry Number: 481-29-8
CAS Name: (3b,5a)-3-Hydroxyandrostan-17-one
Additional Names: 3b-hydroxy-17-androstanone; isoandrosterone; 3b-androstanol-17-one; 3b-hydroxyetioallocholan-17-one
Molecular Formula: C19H30O2
Molecular Weight: 290.44
Percent Composition: C 78.57%, H 10.41%, O 11.02%
Literature References: Present in normal human urine as a minor constituent, it is a less active androgen than androsterone. Synthesis: Cardwell et al., J. Chem. Soc. 1953, 361; Johnson et al., J. Am. Chem. Soc. 75, 2275 (1953); Johnson et al., ibid. 78, 6331 (1956). Review: R. I. Dorfman, R. A. Shipley, Androgens (Wiley, New York, 1956).
Derivative Type: dl-Form
Properties: Crystals, mp 161-162°. Gives off a musk-like odor when hot.
Melting point: mp 161-162°
Derivative Type: d-Form
Properties: Crystals from ethyl acetate + petr ether, mp 174.5°. [a]D20 +88° (in methanol). Precipitated by digitonin. Practically insol in water. Soluble in organic solvents.
Melting point: mp 174.5°
Optical Rotation: [a]D20 +88° (in methanol)
Derivative Type: Acetate
Molecular Formula: C21H32O3
Molecular Weight: 332.48
Percent Composition: C 75.86%, H 9.70%, O 14.44%
Properties: Stout prisms, mp 103-104°. [a]D18 +68.5° (chloroform).
Melting point: mp 103-104°
Optical Rotation: [a]D18 +68.5° (chloroform)
Derivative Type: Benzoate
Molecular Formula: C26H34O3
Molecular Weight: 394.55
Percent Composition: C 79.15%, H 8.69%, O 12.17%
Properties: Crystals, mp 210-212°.
Melting point: mp 210-212°
Epichlorohydrin Epicholestanol Epicholesterol Epicillin Epimedii Herba

Systematic (IUPAC) name
Clinical data
Legal status  ?
CAS number 481-29-8
ATC code None
PubChem CID 441302
ChemSpider 390065 YesY
UNII 8TR252Z538 YesY
ChEBI CHEBI:541975 YesY
Chemical data
Formula C19H30O2 
Mol. mass 290.440 g/mol
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Epiandrosterone, or 3β-androsterone, also known as 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.[1]

Epiandrosterone is naturally produced by the enzyme 5α-reductase from the adrenal hormone DHEA.[2][3][4][5][verification needed] Epiandrosterone can also be converted from the natural steroids androstanediol via 17β-hydroxysteroid dehydrogenase or from androstanedione via 3β-hydroxysteroid dehydrogenase.[citation needed]