Arimistane

Arimistane, chemically androsta-3,5-diene-7,17-dione, is a steroidal compound marketed as an aromatase inhibitor in over-the-counter bodybuilding and post-cycle therapy supplements. It is closely related to 7-keto-DHEA (7-oxo-DHEA); indeed, analytical studies have shown that arimistane forms as a degradation product of 7-keto-DHEA under acidic or high-temperature conditions, which has complicated its interpretation in laboratories ^[3][4]. It is an androstadienedione, part of the 7-oxygenated androstene family, rather than a pharmaceutical drug developed through clinical trials.

Marketed claims center on estrogen control; as a suicide aromatase inhibitor it is promoted to lower estrogen and support testosterone, and it is sold as a standalone estrogen blocker and as an ingredient in prohormone and testosterone-support products. However, the scientific literature on arimistane is almost entirely analytical and anti-doping in nature rather than clinical. Arimistane is on the World Anti-Doping Agency Prohibited List as an aromatase inhibitor, and forensic groups have developed gas chromatography and liquid chromatography mass spectrometry methods to detect it and its urinary metabolites, identifying more than a dozen metabolites after a controlled oral dose ^[1][2]. It has also been found as an undeclared adulterant in dietary supplements sold for anabolic benefit ^[5].

Arimistane has no marketing authorization as a medicine and has not undergone formal efficacy or safety trials in humans. Notably, a controlled administration study found no relevant change in the urinary steroid profile after a single oral dose, raising questions about how much systemic hormonal effect it actually exerts ^[1]. It is sold as a powder or in capsules on the supplement market, where it sits in a legal gray area and is banned for competitive athletes ^[5].

Arimistane (androsta-3,5-dien-7,17-dione) is a compound sold over the counter as an aromatase inhibitor to lower estrogen, and although marketed as a supplement its human safety data are limited. By suppressing estrogen it can cause joint pain and dryness, reduced bone density with prolonged use, unfavorable lipid changes, fatigue, and low-estrogen effects on mood and libido; it may also cause a positive athletic drug test.

Arimistane, chemically androsta-3,5-diene-7,17-dione, has no formal pharmaceutical discovery history; it appeared in the 2010s as an ingredient in bodybuilding supplements marketed for estrogen control and post-cycle therapy rather than as a drug developed through clinical research. It is closely related to, and is a known degradation product of, 7-keto-DHEA, which complicates its analytical identification. Most of the peer-reviewed literature on the compound comes not from efficacy studies but from anti-doping science, where investigators have mapped its urinary metabolites to enable detection. The World Anti-Doping Agency lists it as a prohibited substance, and its human pharmacology remains only lightly characterized.

Within the supplement and bodybuilding community, arimistane has a following as an over-the-counter aromatase inhibitor used to blunt estrogen and support testosterone recovery, and users often report subjective effects on water retention and mood. It is honest to note, however, that this reputation rests largely on anecdote and mechanism on paper rather than controlled human trials; one controlled administration study found no relevant change in the urinary steroid profile despite abundant metabolites. Researchers value the compound mainly as a well-studied analytical target in anti-doping work. Anyone subject to drug testing should be aware that it is a banned substance in sport.