The 17α-ethenylated (vinylated) testosterone derivative norvinisterone (vinylnortestosterone) is much more potent as an AAS than the 17α-ethynylated testosterone derivatives and is intermediate in potency between the 17α-ethynylated progestins and conventional AAS, with approximately one-third and one-fifth of the respective androgenic and anabolic activity of nandrolone in animalbioassays.
Vinyltestosterone has been described as a weak AAS, though stronger than its 17α-ethynylated analogue ethisterone.
17α-Ethynylated testosterone derivatives are potent progestins with only very weak androgenic/anabolic activity and are used as oral contraceptives or for the treatment of gynecological conditions in women. They are invariably classified as progestins rather than as AAS. However, these progestins are testosterone derivatives and do have significant androgenic/anabolic activity, sometimes producing acne and other mild androgenic effects in women. Conversely, in men, these drugs may actually have functional antiandrogen effects due to their potent progestogenic and hence antigonadotropic activity and capacity to suppress gonadal testosterone production.
^Paulsen, C. Alvin; Leach, Robert B.; Lanman, John; Goldston, Norman; Maddock, W. O.; Heller, Carl G. (1962). "Inherent Estrogenicity of Norethindrone and Norethynodrel: Comparison with Other Synthetic Progestins and Progesterone1". The Journal of Clinical Endocrinology & Metabolism. 22 (10): 1033–1039. doi:10.1210/jcem-22-10-1033. ISSN0021-972X. PMID13942007. Androgenic effects were absent for each of the compounds in the doses administered as judged by: (a) marked decrease in libido and sexual potentia in each of 21 normal male subjects receiving norethynodrel, norethindrone and norethandrolone; (b) failure to increase libido and sexual potentia in each of four hypogonadotrophic eunuchoidal men receiving norethandrolone (each had previously responded to testosterone administration); (c) no virilization of 14 of 15 postmenopausal women receiving the three progestins (one who was taking norethandrolone at the dose level of 30 mg daily noted lowering in the pitch of her voice during the second month of therapy).
Fragkaki AG, Angelis YS, Koupparis M, Tsantili-Kakoulidou A, Kokotos G, Georgakopoulos C (2009). "Structural characteristics of anabolic androgenic steroids contributing to binding to the androgen receptor and to their anabolic and androgenic activities. Applied modifications in the steroidal structure". Steroids. 74 (2): 172–97. doi:10.1016/j.steroids.2008.10.016. PMID19028512.
McRobb L, Handelsman DJ, Kazlauskas R, Wilkinson S, McLeod MD, Heather AK (2008). "Structure-activity relationships of synthetic progestins in a yeast-based in vitro androgen bioassay". J. Steroid Biochem. Mol. Biol. 110 (1–2): 39–47. doi:10.1016/j.jsbmb.2007.10.008. PMID18395441.