Ostarine, also known as MK-2866 or Enobosarm, is a type of drug called a selective androgen receptor modulator (SARM) . It is not approved by the FDA and is banned by the World Anti-Doping Agency (WADA) and the National Collegiate Athletic Association (NCAA) . Ostarine attaches to proteins in the body known as androgen receptors, which tells muscles to grow. People use Ostarine for athletic performance, involuntary weight loss due to illness, breast cancer, and many other conditions, but there is no good scientific evidence to support these uses. Ostarine is currently being investigated as a way to treat a variety of muscle-wasting diseases, such as osteoporosis, cancer, and hypogonadism. Despite not being approved for human use or consumption in the US or any other country, Ostarine is still sometimes found in dietary supplements, particularly those marketed for bodybuilding. Ostarine is one of the most popular SARMs due to its mild side effects and its all-around ability. It can be used for fat loss, muscle building, and bulking and get decent results for all three (depending on what your goals are) .