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Mestanolone Structural Formula V2.svg
Clinical data
Trade namesAndrostalone, Ermalone, others
Other namesRU-143; Methylandrostanolone; Methyldihydrotestosterone; Methyl-DHT; 17α-Methyl-4,5α-dihydrotestosterone; 17α-Methyl-DHT; 17α-Methyl-5α-androstan-17β-ol-3-one;
AHFS/Drugs.comInternational Drug Names
  • US: X (Contraindicated)
Routes of
By mouth
Drug classAndrogen; Anabolic steroid
ATC code
  • None
Legal status
Legal status
Pharmacokinetic data
CAS Number
PubChem CID
CompTox Dashboard (EPA)
ECHA InfoCard100.007.549 Edit this at Wikidata
Chemical and physical data
Molar mass304.474 g·mol−1
3D model (JSmol)
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Mestanolone, also known as methylandrostanolone and sold under the brand names Androstalone and Ermalone among others, is an androgen and anabolic steroid (AAS) medication which is mostly no longer used.[1][2][3][4] It is still available for use in Japan however.[2][3] It is taken by mouth.[4]

Side effects of mestanolone include symptoms of masculinization like acne, increased hair growth, voice changes, and increased sexual desire.[4] It can also cause liver damage.[4] The drug is a synthetic androgen and anabolic steroid and hence is an agonist of the androgen receptor (AR), the biological target of androgens like testosterone and dihydrotestosterone (DHT).[4][5] It has strong androgenic effects and weak anabolic effects, which make it useful for producing masculine psychological and behavioral effects.[4] The drug has no estrogenic effects.[4]

Mestanolone was discovered in 1935 and was introduced for medical use in the 1950s.[6][7][8][4] In addition to its medical use, mestanolone has been used to improve physique and performance.[4] It was used in East Germany in Olympic athletes as part of a state-sponsored doping program in the 1970s and 1980s.[4] The drug is a controlled substance in many countries and so non-medical use is generally illicit.[4]

Medical uses[edit]

Available forms[edit]

Mestanolone was available in the form of 25 mg sublingual tablets (brand name Ermalone).[9]



Mestanolone is an AAS, with both androgenic and anabolic effects.[4] It is very similar in its effects to androstanolone (dihydrotestosterone; DHT), and can be thought of as an orally active version of this AAS.[4] Due to inactivation by 3α-hydroxysteroid dehydrogenase (3α-HSD) in skeletal muscle, mestanolone is described as a very poor anabolic agent, similarly to androstanolone and mesterolone.[4] As mestanolone is 5α-reduced, it cannot be aromatized and hence has no propensity for estrogenic side effects such as gynecomastia.[4] The drug also has no progestogenic activity.[4] Like other 17α-alkylated AAS, mestanolone is hepatotoxic.[4]


Due to its C17α methyl group, unlike androstanolone, mestanolone is orally active.[4]


Mestanolone, also known as 17α-methyl-4,5α-dihydrotestosterone (17α-methyl-DHT) or as 17α-methyl-5α-androstan-17β-ol-3-one, is a synthetic androstane steroid and a 17α-alkylated derivative of dihydrotestosterone (DHT).[1][4] It differs from DHT only by the presence of the methyl group at the C17α position.[1][4] Close synthetic relatives of mestanolone include oxandrolone (2-oxa-17α-methyl-DHT), oxymetholone (2-hydroxymethylene-17α-methyl-DHT), and stanozolol (a derivative of 17α-methyl-DHT (mestanolone) with a pyrazole ring fused to the A ring).[1][4]

Side effects[edit]

Side effects of mestanolone include virilization and hepatotoxicity among others.[4]


Mestanolone was first synthesized in 1935 along with methyltestosterone and methandriol.[6][7] It was developed by Roussel in the 1950s and was introduced for medical use, under the brand names Androstalone and Ermalone, by at least 1960.[4][10][8] It was marketed in Germany.[4] The drug was originally thought to be a potent anabolic agent, but subsequent research showed that it actually has relatively weak anabolic effects and is mostly an androgen.[4] Mestanolone was used as a doping agent in athletes competing in the Olympics from East Germany due to a state-sponsored doping program in the 1970s and 1980s.[4] Its value is said to have been less as a muscle-builder and more as an androgen in the central nervous system and neuromuscular interaction, improving speed, strength, aggression, focus, endurance, and stress resilience.[4] Today, mestanolone has mostly been discontinued in medicine, though it is still available in Japan.[2][3][4]

Society and culture[edit]

Generic names[edit]

Mestanolone is the generic name of the drug and its INN, BAN, and JAN.[1][11]

Brand names[edit]

Mestanolone was marketed under the brand names Andoron, Androstalone, Ermalone, Mesanolon, and Notandron among many others.[4][2][12][3]


Mestanolone has mostly been discontinued but remains available in Japan.[2][3][4]


  1. ^ a b c d e J. Elks (14 November 2014). The Dictionary of Drugs: Chemical Data: Chemical Data, Structures and Bibliographies. Springer. pp. 775–. ISBN 978-1-4757-2085-3.
  2. ^ a b c d e Index Nominum 2000: International Drug Directory. Taylor & Francis. 2000. pp. 655–. ISBN 978-3-88763-075-1.
  3. ^ a b c d e
  4. ^ a b c d e f g h i j k l m n o p q r s t u v w x y z aa ab ac ad William Llewellyn (2009). Anabolics. Molecular Nutrition Llc. p. 241. ISBN 978-0967930473.
  5. ^ Kicman AT (2008). "Pharmacology of anabolic steroids". Br. J. Pharmacol. 154 (3): 502–21. doi:10.1038/bjp.2008.165. PMC 2439524. PMID 18500378.
  6. ^ a b Schänzer W (1996). "Metabolism of anabolic androgenic steroids". Clin. Chem. 42 (7): 1001–20. doi:10.1093/clinchem/42.7.1001. PMID 8674183.
  7. ^ a b Ruzicka, L.; Goldberg, M. W.; Rosenberg, H. R. (1935). "Sexualhormone X. Herstellung des 17-Methyl-testosterons und anderer Androsten- und Androstanderivate. Zusammenhänge zwischen chemischer Konstitution und männlicher Hormonwirkung". Helvetica Chimica Acta. 18 (1): 1487–1498. doi:10.1002/hlca.193501801203. ISSN 0018-019X.
  8. ^ a b Arnold A, Potts GO, Beyler AL (1963). "The Ratio of Anabolic to Androgenic Activity of 7: 17-Dimethyltestosterone, Oxymesterone, Mestanolone and Fluoxymesterone". J. Endocrinol. 28: 87–92. doi:10.1677/joe.0.0280087. PMID 14086172.
  9. ^ H.-L. Krüskemper (22 October 2013). Anabolic Steroids. Elsevier. pp. 196–. ISBN 978-1-4832-6504-9.
  10. ^ Bishop PM (1960). "Male Sex Hormones". Br Med J. 1 (5167): 184–6. doi:10.1136/bmj.1.5167.184. PMC 1966335. PMID 13800998.
  11. ^
  12. ^ Martin Negwer (1987). Organic-chemical Drugs and Their Synonyms: (an International Survey). VCH Publishers. ISBN 978-0-89573-552-2. Anavormol, Andoron, Androne, Androstalone, Antalon “Kobayashi K.”, Assimil, Ermalone, Etnabolate, Hermalone-Glosset, Macrobin (Tabl. -- Syrup), Mesanolon, Mestalone, Mestanolone”, Methyantalon, Methybol, 172-Methylandrostanolone, Preroide,. 1045.