methylhydroxynandrolone methylhydroxynandrolone methylhydroxynandrolone (mohn, mhn), also known as 4-hydroxy-17α-methyl-19-nortestosterone (hmnt), as well as 4,17β-dihydroxy-17α-methylestr-4-en-3-one, is a synthetic, orally active anabolic–androgenic steroid (aas) and a 17α-alkylated derivative of nandrolone (19-nortestosterone) which was never marketed. it was first described in 1964 and was studied in the treatment of breast cancer, but was not introduced for clinical use. the drug re-emerged in 2004 when it started being sold on the internet as a "dietary supplement". mohn joined other aas as a controlled substance in the united states on 20 january 2005. methylhydroxynandroloneclinical dataother namesmohn; mhn; 4-hydroxy-17α-methyl-19-nortestosterone; hmnt; 4,17β-dihydroxy-17α-methylestr-4-en-3-oneroutes ofadministrationby mouthdrug classandrogen; anabolic steroididentifiers iupac name 4,17-dihydroxy-13,17-dimethyl-1,2,6,7,8,9,10,11,12,14,15,16-dodecahydrocyclopentaphenanthren-3-one cas number2747-16-2pubchem cid351707chemspider312271uniial9hua7c4cchemical and physical dataformulac19h28o3molar mass304.430 g·mol−13d model (jsmol)interactive image smiles cc12ccc3c(c1ccc2(c)o)ccc4=c(c(=o)ccc34)o inchi inchi=1s/c19h28o3/c1-18-9-7-12-11-5-6-16(20)17(21)14(11)4-3-13(12)15(18)8-10-19(18,2)22/h11-13,15,21-22h,3-10h2,1-2h3key:clnuzocykshicx-uhfffaoysa-n mohn is non-aromatizable due to the presence of a hydroxy group at the c4 position, and for this reason, poses no risk of estrogenic side effects like gynecomastia at any dosage, unlike many other aas. 5α-reduction is also inhibited by the c4 hydroxy group of mohn and, because of this, mohn may have a relatively higher ratio of androgenic to anabolic activity than other nandrolone derivatives (as 5α-reduction, opposite to the case of most other aas, decreases aas potency for most nandrolone derivatives). early assays found that mohn had approximately 13 times the anabolic activity and 3 times the androgenic activity of methyltestosterone. mohn is the 4-hydroxylated derivative of normethandrone (17α-methyl-19-nortestosterone), the 17α-methylated derivative of oxabolone (4-hydroxy-19-nortestosterone), the 4-hydroxylated and 17α-methylated derivative of nandrolone (19-nortestosterone), and the 19-demethylated analogue of oxymesterone (4-hydroxy-17α-methyltestosterone).