GW1516 (also known as Endurobol) ) is not a steroid; it is a selective agonist of peroxisome proliferator-activator receptors (PPARs). It was originally developed for the treatment of obesity, diabetes mellitus, dyslipidemia and cardiovascular diseases. 

GW1516 has a wide variety of effects in the body such as cell energy processes, insulin production, fatty acid oxidation, and even has a positive impact on muscle inflammation.    

GW1516 activates adenosine monophosphate-activated protein kinase (enzyme involved in energy processes in our body) and thus stimulates glucose uptake in skeletal muscle tissue. In studies GW1516 demonstrated the ability to restore the metabolic disorder in obese men with prediabetes syndrome, most likely by stimulation of fatty acid oxidation.

In studies GW1516 has shown muscular protective and enhancing effects and this seems to be related to a decrease in muscle inflammation and damage. GW1516 has shown to elicit cardiovascular protection possibly due to its actions in decreasing insulin spikes and stabilizing cholesterol levels as found in research. It is noticeable, that GW1516 not just decreases very-low-density lipoproteins (VLDL), but also increases high-density lipoproteins (HDL), what is the result of increased expression of the cholesterol transporter ABCA1, caused by GW1516. 

From the very beginning GW-1516 was accompanied by a defamatory information. The World Anti-Doping Agency (WADA) put it into the list of hazardous to health drugs, justifying this action by the statement that the drug may allegedly contribute to carcinogenesis. So, according to research from GlaxoSmithKline, the drug caused cancer in rats. In these studies subjected rats were administrated by unphysiologic dosages of 10 mg/kg of body weight. Let`s draw an analogy with a human: for a 200lb (roughly 90 kg) man such dose would be equal to 900 mg per day. These dosages defy any common sense, let alone that it can`t be compared with a standard compound dose of 20 mg per day. 900 mg/day of GW1516 is comparable to taking 14625 mg of aspirin per day (while its standard single dose does not exceed 325 mg). Forget cancer, this dosage of aspirin could literally KILL you!

There are two main uses of  GW1516 is sport. First, to increase endurance. The test results showed increase of endurance in rats by 68% while running on a treadmill when taking GW1516. A common dose of 10 mg/day will ensure a substantial enhancement in endurance. When used in bodybuilding GW1516 can significantly reduce rest time between sets.

The second reason to use GW1516 is fat burning. The drug has shown the ability to burn fat, while still being non-catabolic, it means, it helps burn fat and keep muscles.

In fact, GW1516 has not shown any significant side effects. There is no hormones suppression, no toxicity and no other common side effects.  The only thing that should be noted is that GW1516 significantly activates metabolism and contributes to the rapid consumption of glycogen during exercises, so do not exceed recommended dosages; otherwise signs of hypoglycemia (weakness, drowsiness, hunger, muscular cramps, in severe cases - loss of consciousness) may occur. If you feel some of these signs, immediately eat something sweet (containing fast carbs).