Dimethandrolone

Dimethandrolone (DMA) (developmental code name CDB-1321), also known as 7α,11β-dimethyl-19-nortestosterone, is a potent, synthetic, orally active androgenic-anabolic steroid (AAS) or selective androgen receptor modulator (SARM) and progestogen of the 19-nortestosterone group related to nandrolone that was developed by the Contraceptive Development Branch (CDB) of the National Institute of Child Health and Human Development (NICHD). The 17β-undecanoate ester of dimethandrolone, dimethandrolone undecanoate (DMAU) (CDB-4521), is a prodrug of dimethandrolone that is cleaved by esterases and is under investigation as a method of androgen replacement therapy and as a potential male contraceptive. A number of other esters, such as dimethandrolone buciclate (CDB-4386A) and dimethandrolone dodecylcarbonate (CDB-4730), have also been developed.

Unlike testosterone and various other AAS, dimethandrolone is not metabolized by 5α-reductase. In addition, the 5α-reduced derivative of dimethandrolone, 5α-dihydrodimethandrolone (5α-DHDMA), possesses only 30 to 40% of the potency of dimethandrolone as an agonist of the androgen receptor, indicating that dimethandrolone does not require potentiation by 5α-reductase for its activity as an AAS and that even if it were a substrate for 5α-reductase, it would not be potentiated in androgenic tissues like the skin and prostate. As such, dimethandrolone and ester prodrugs of it like DMAU are thought to have a reduced risk of androgenic side effects and conditions such as benign prostate hyperplasia, prostate cancer, androgenetic alopecia, and acne relative to testosterone and certain other AAS.

Dimethandrolone is not a substrate for aromatase, and for this reason, is not converted into the corresponding aromatic A-ring derivative 7α,11β-dimethylestradiol, a potent estrogen. As such, dimethandrolone is not estrogenic. This is in contrast to nandrolone, which, although its rate of aromatization into the estrogen estradiol is reduced relative to that of testosterone, is still converted to a significant extent.

Similarly to nandrolone and other 19-nortestosterone derivatives, dimethandrolone is a potent progestogen in addition to AAS. This property may serve to augment its antigonadotropic activity, which in turn may improve its effectiveness as an antispermatogenic agent and male contraceptive. This is salient and potentially beneficial as male contraceptives based on androgens alone have failed to produce satisfactory azoospermia in around one-third of men.

Dimethandrolone has shown minimal potential for hepatotoxicity in animal studies, which is in accordance with the fact that it is not a 17α-alkylated AAS.

Other drugs that are closely related to dimethandrolone (besides nandrolone) include trestolone (also known as 7α-methyl-19-nortestosterone (MENT)) and 11β-methyl-19-nortestosterone (11β-MNT) and their respective C17β esters trestolone acetate and 11β-MNT dodecylcarbonate (11β-MNTDC).