11β-Methyl-19-nortestosterone (11β-MNT) is a synthetic and orally active anabolic–androgenic steroid (AAS) and a derivative of nandrolone (19-nortestosterone). It was developed by the Contraceptive Development Branch (CDB) of the National Institute of Child Health and Human Development (NICHD) and has not been marketed as of the time of this writing.
Overview and Development
11β-MNT is a non-17α-alkylated derivative of nandrolone. Its C17β dodecyl carbonate ester, 11β-methyl-19-nortestosterone 17β-dodecylcarbonate (11β-MNTDC; developmental code name CDB-4754), serves as a prodrug of 11β-MNT. Along with the closely related AAS dimethandrolone (7α,11β-dimethyl-19-nortestosterone; CDB-1321) and its ester prodrug dimethandrolone undecanoate (CDB-4521), 11β-MNT and 11β-MNTDC have been under investigation as potential male contraceptives and for the treatment of male hypogonadism.
Pharmacology
11β-MNT does not undergo aromatization into the corresponding estrogenic metabolite 11β-methylestradiol, and therefore has no potential for estrogenic side effects such as gynecomastia. In addition, unlike testosterone, 11β-MNT does not appear to undergo 5α-reduction into the corresponding 5α-dihydrogenated metabolite 5α-dihydro-11β-MNT. This conclusion is based on the observation that 5α-DHMNT is 4 to 8 times as potent as 11β-MNT in terms of androgenicity in animal bioassays, yet co-administration of the 5α-reductase inhibitor dutasteride with 11β-MNT had no influence on its potency in assays using tissues that express 5α-reductase, such as the ventral prostate and seminal vesicles. Due to the lack of potentiation by 5α-reductase in androgenic tissues like the skin, hair follicles, and prostate gland, 11β-MNT may carry a lower risk of certain side effects such as oily skin, acne, androgenic alopecia (pattern hair loss), prostate enlargement, and prostate cancer compared with testosterone and certain other AAS.
Similarly to nandrolone, dimethandrolone, and other 19-nortestosterone derivatives, 11β-MNT possesses progestogenic activity. Because of its dual activity as an AAS and progestogen, 11β-MNT may have greater efficacy in suppressing spermatogenesis and hence male fertility than pure AAS like testosterone.
Oral 11β-MNT has shown little to no potential for hepatotoxicity in animals, similarly to testosterone but unlike 17α-alkylated AAS such as methyltestosterone. The drug notably shows a much lower hepatotoxic potential than dimethandrolone and trestolone (7α-methyl-19-nortestosterone; MENT), which may carry an increased risk due to their shared C7α methyl group (though still significantly lower than that of 17α-alkylated AAS).
Chemistry
11β-MNT, also known as 11β-methylestr-4-en-17β-ol-3-one, is a synthetic estrane steroid. Its chemical formula is C19H28O2, with a molar mass of 288.431 g·mol⁻¹. Its CAS number is 18046-77-0 (with 904901-01-5 for the dodecylcarbonate form), and its PubChem CID is 68648057.
Route of Administration
11β-MNT is administered by mouth (oral route).
