MK-3984

MK-3984 is a nonsteroidal selective androgen receptor modulator (SARM). It has the molecular formula C17H12F7NO2 and a molar mass of roughly 395, is registered under CAS number 871325-55-2, and carries the systematic name (2R)-3,3,3-trifluoro-N-[[2-fluoro-5-(trifluoromethyl)phenyl]methyl]-2-hydroxy-2-phenylpropanamide. The MK prefix marks it as a compound from Merck Sharp and Dohme.

SARMs are a class of drugs that bind the androgen receptor but act with tissue selectivity: they behave as anabolic agonists in muscle and bone while producing much weaker androgenic activity in tissues such as the prostate and skin. Because they are orally active and are not converted to estrogen, they were pursued as a way to gain the muscle- and bone-building benefits of androgens with fewer side effects than testosterone. MK-3984 was one of a number of SARM candidates explored for indications including the muscle wasting that accompanies cancer and the bone loss of osteoporosis ^[1][2].

Despite this interest, MK-3984 did not advance to approved medical use and its development program was ended. It has no license as a medicine in any country. Like other discontinued SARMs it has surfaced in the gray-market supplement trade, where it is sold as a research chemical rather than a regulated drug, and strong performance claims about it are not backed by clinical evidence.

Because SARMs are banned in competitive sport, MK-3984 has more recently drawn attention from anti-doping science. A 2026 study mapped its metabolic breakdown products in a zebrafish model in order to establish markers for detecting its use in athletes ^[3]. Human safety and efficacy data for the compound remain absent.

Because there is no reliable safety data, MK-3984 should be considered unknown and potentially risky. Gray-market products may be mislabeled or contaminated. Using it is not advisable, and anyone considering it should recognize they are essentially self-experimenting with an uncharacterized compound.