RAD-140, also known as Testolone, is a non-steroidal selective androgen receptor modulator (SARM) designed to mimic the anabolic effects of testosterone with greater tissue selectivity. It binds specifically to androgen receptors in muscle and bone, activating anabolic pathways without significantly affecting other androgen-responsive tissues, such as the prostate.

Research on RAD-140 has focused on its potential to increase lean muscle mass, enhance strength, and support bone density, while minimizing the risk of typical androgenic side effects. Unlike traditional anabolic steroids, RAD-140 does not undergo aromatization to estrogen, which reduces the risk of estrogen-related complications. It has also been investigated for its neuroprotective properties and possible applications in hormone replacement therapy, especially in scenarios requiring anabolic support without full-spectrum androgen exposure.