Trestolone is a synthetic androgen that inhibits the release of follicle-stimulating hormone and impairs spermatogenesis. Luteinizing hormone is also suppressed, which cuts production of testosterone. The azoospermia and oligospermia are reversible after discontinuation of trestolone. Trestolone has androgenic and anabolic properties and loss of secondary sex characteristics is not seen. Like testosterone, trestolone undergoes enzymatic aromatization to an estrogen. The use of trestolone instead of testosterone for androgen replacement therapy could have health-promoting effects by reducing the occurrence of prostate disease. Trestolone had been in phase II clinical trial for the andropause control. However, this development was discontinued.

Stenbolone is an anabolic–androgenic steroid of the dihydrotestosterone group patented by Schering AG but never marketed. Ester prodrug of stenbolone is used as an anabolic–androgenic steroid for depot intramuscular injection under the brand names Anatrofin and Stenobolone.

Nisterime is a dihydrotestosterone derivative. Nisterime acetate (ORF-9326) was shown to inhibit implantation in several species. It is also interrupts the postimplantation stage of gestation.

Cobalt is a transition metal, naturally ocurring in the minerals cobaltite, smaltite, and erythrite, and is often associated with nickel, silver, lead, copper, and iron ores, from which it is most frequently obtained as a by-product. Depending on the considered species, cobalt has multiple industrial applications including the production of alloys and hard metal, diamond polishing, drying agents, pigments and catalysts. Cobalt is an essential component of Vitamin B12 (hydroxycolalamin). Cobalt functions as a co-factor in enzyme catalysed reactions and is involved in the production of erythropoietin, a hormone that stimulates the formation of erythrocytes. Cobalt salts were used to treat anemia and stimulate erythropoiesis, but was withdrawn from market since Co(II) cations are genotoxic in vitro and in vivo, and carcinogenic in rodents. Hovewer, Co salts are reported to be used by athletes as a doping