Ostarine (also known as MK-2866 or Enobosarm) is a selective androgen receptor modulator (SARM) that has been studied for its potential to increase muscle mass and strength. The use of Ostarine to support exercise performance or muscle building is primarily supported by scientific research, particularly in the context of preventing muscle wasting in clinical populations (such as those with cancer cachexia or age-related sarcopenia). Several randomized controlled trials and early-phase clinical studies have shown that Ostarine can lead to increases in lean body mass and improvements in physical function compared to placebo. For example, a phase II trial published in the Journal of Cachexia, Sarcopenia and Muscle (2011) demonstrated that Ostarine significantly increased lean mass and improved muscle strength in elderly men and postmenopausal women.

However, while these findings provide moderate scientific validation for Ostarine’s anabolic effects, the evidence specifically supporting its use in healthy athletes or for enhancing exercise performance is limited. Most studies have focused on populations with muscle wasting, not on recreational or competitive athletes. Furthermore, Ostarine is not approved by regulatory agencies for muscle building or exercise enhancement, and it is banned by the World Anti-Doping Agency (WADA). Long-term safety data are also lacking. Thus, while there is scientific support for its anabolic activity, its use to support exercise in healthy individuals is not robustly validated.