GW1516, also called Endurobol, is not a steroid. It works by activating PPAR receptors, which play a key role in how the body uses energy. It was first developed to help treat obesity, diabetes, cholesterol problems, and heart-related conditions.

GW1516 supports many processes in the body. It improves how cells use energy, helps control insulin levels, increases fat burning, and may reduce muscle inflammation. It also activates AMPK, an enzyme that helps muscles absorb glucose more efficiently. Studies showed that GW1516 helped improve metabolic function in overweight men with prediabetes by boosting fat oxidation.

Research also suggests that GW1516 helps protect muscle tissue. This benefit is linked to lower muscle damage and reduced inflammation. In addition, it may support heart health by keeping insulin levels stable and improving cholesterol balance. GW1516 lowers bad cholesterol (VLDL) while raising good cholesterol (HDL). This happens because it increases the activity of a cholesterol transporter called ABCA1.

From early on, GW1516 received negative attention. The World Anti-Doping Agency listed it as a health risk after animal studies showed cancer in rats. However, those rats were given extremely high doses—about 10 mg per kilogram of body weight. For a human weighing around 90 kg (200 lbs), that would equal roughly 900 mg per day. This amount is far beyond normal use. To put it in perspective, it would be like taking over 14,000 mg of aspirin in one day, which would be dangerous. Standard GW1516 use is around 20 mg per day, making those study doses unrealistic.

In sports, GW1516 is mainly used for two reasons. The first is endurance. Tests showed a large increase in running endurance in animals. Even a low daily dose of around 10 mg can noticeably improve stamina. In bodybuilding, this often means shorter rest times between sets.

The second reason is fat loss. GW1516 helps the body burn fat without breaking down muscle tissue, making it useful during cutting phases.

GW1516 has not shown major side effects in normal use. It does not suppress hormones and is not toxic. One thing to watch is low blood sugar. Because it speeds up metabolism and uses glycogen quickly, taking too much can cause weakness, dizziness, hunger, or muscle cramps. If this happens, consuming fast carbohydrates can help quickly.