Trimethyltrienolone
[1][2][3] Due to its close relation to metribolone (methyltrienolone), it is thought that TMT may produce hepatotoxicity.[4] TMT is a selective and highly potent competitive antagonist of the androgen receptor (AR) with very low intrinsic/partial androgenic activity and no estrogenic, antiestrogenic, progestogenic, or antimineralocorticoid activity.[5][6] The drug is a derivative of the extremely potent androgen/anabolic steroid metribolone (R-1881; 17α-methyltrenbolone),[6][7] and has been reported to possess only about 4-fold lower affinity for the AR in comparison.[9] The AR weak partial agonistic activity of TMT is comparable to that of cyproterone acetate.[5][17][18][19][20] The drug was under investigation by Roussel Uclaf for potential medical use, but was abandoned in favor of nonsteroidal antiandrogens like flutamide and nilutamide due to their comparative advantage of a complete lack of androgenicity.