Cardarine
GW501516 (cardarine)
Also known as: GW501516, GW-501516, Endurobol
A PPAR-delta agonist that GSK abandoned in 2007 after long-term rodent studies produced cancers in multiple organs; still sold widely for endurance and fat loss despite the signal and a WADA ban.
Overview
Cardarine shifts muscle toward fat oxidation and in the 2008 Cell paper combined with training to raise mouse endurance. Development stopped when two-year rodent studies showed tumors in the liver, bladder, stomach, skin, thyroid and other tissues. There are no human efficacy trials, WADA prohibits it, and health regulators including Health Canada have seized products as recently as 2025.
Mechanism of action
PPAR-delta agonism that upregulates fatty-acid oxidation genes in skeletal muscle.
Key studies & citations
- Animal2008
AMPK and PPARdelta agonists are exercise mimetics
GW501516 plus training improved endurance in mice.
Cell - Animal2009
GW501516 carcinogenicity in rodents (regulatory summaries)
Multi-organ tumors in two-year rodent studies ended development.
PubMed search
Frequently asked questions
How real is the cancer risk?
Real enough that the manufacturer stopped development. The rodent studies were long-term and showed tumors in many organs; no human safety study exists to argue otherwise.