WADA issues warning on black market GW501516

The World Anti-Doping Agency has taken a rare step to warn athletes about toxicity of a potential doping substance known as GW501516. The drug, developed by GlaxoSmithKline, was withdrawn from research studies after mice showed increased incidence of tumors when dosed with the substance.

The experimental drug was being developed as a potential to raise HDL cholesterol or "good" cholesterol, but according to a GlaxoSmithKline spokesperson, the development was halted in 2006.

Although GW501516 never made it through the clinical approval process, it has already made it out onto the black market, and anecdotes of athletes it can be found in fitness forums. The drug has been shown to stimulate the same metabolic pathways that are activated through exercise, and together with the drug AICAR (Acadesine) was shown to increase endurance in animal experiments.

Both substances are banned by the WADA code, and doping controls can detect the drugs. But that has not stopped some athletes from experimenting with them, and according to WADA, anti-doping authorities have already noted "a number of positive cases".

"GW501516 is not approved for use in humans and GSK does not manufacture or authorize its sale," said GSK's Melinda Stubbee. "Furthermore, GSK is not affiliated in any way with Uniquemicals or any other suppliers of GW501516."

WADA took the unusual step to warn potential "cheats" about the toxicity, "to ensure that there is complete awareness of the possible health risks to athletes who succumb to the temptation of using GW501516 for performance enhancement".