Cardarine (GW-501516, PPARδ agonist)
Cardarine (GW-501516) is not a SARM but a PPARδ agonist, developed for dyslipidaemia and studied for its effects on fat metabolism and endurance. Development was halted after long-term rodent studies showed dose-dependent cancers in multiple organs. This carcinogenicity signal is the dominant safety concern; whether it translates to humans is disputed and unresolved.
01 Overview
GW-501516 activates the peroxisome proliferator-activated receptor delta, shifting metabolism toward fatty-acid oxidation. Early human trials showed favourable changes in lipids and markers of fat metabolism, and animal work suggested enhanced endurance, driving its reputation as an endurance and fat-loss agent.
GlaxoSmithKline discontinued development after two-year rodent studies produced tumours across several tissues at a range of doses. Because those studies used high doses over an animal lifetime, the human relevance is disputed, but the signal was serious enough to end clinical work. It is banned in sport and sold only as a research chemical. It does not suppress testosterone, so no steroid profile applies.
02 Mechanism
Agonist of PPARδ, upregulating genes for fatty-acid oxidation and metabolic adaptation in muscle; not an androgen and does not bind the androgen receptor.
03 Dosing
| Tier | Dose | Route | Notes |
|---|---|---|---|
| Light | 10 mg/day | Oral | Anecdotal endurance/fat-loss range; carcinogenicity signal makes any use high-risk. |
| Common | 10–20 mg/day | Oral | Higher anecdotal range; no safe dose established. |
04 Effects
| Effect | Magnitude | Evidence | |
|---|---|---|---|
| Improved lipid profileShort human trials showed favourable changes in HDL, LDL and triglycerides. | raised HDL, lowered triglycerides | Clinical | |
| Increased enduranceRodent studies showed enhanced running endurance; not confirmed in humans. | Preclinical | ||
| Enhanced fat oxidationAnimal and mechanistic data show a shift toward fatty-acid metabolism. | Preclinical |
05 Side effects
| Effect | Severity | Frequency | Evidence | Countermeasures |
|---|---|---|---|---|
| Carcinogenicity signalTwo-year rodent studies showed dose-dependent tumours in multiple organs, ending clinical development. Human relevance is disputed and unresolved, but this is the central reason the compound was abandoned. | Life-threatening | Unknown in humans | Disputed | |
| Unknown long-term metabolic effectsLong-term human safety was never established because development stopped early. | Moderate | Unknown | Unconfirmed |