Evidence review: Open Peptide Project (verified against primary PubMed, ClinicalTrials.gov & FDA records) · Last checked 2026-10-27. ← Back to Evidence Library

Cardarine (GW501516): what the evidence says

Name: Cardarine (GW501516)
Published: 2026-10-27

At a glance

What it is: a small-molecule PPAR-delta agonist, not a peptide, sold beside peptides on research-chemical sites. ^R1 It was a GlaxoSmithKline development drug for raising HDL cholesterol. UNVERIFIED co-developer details.

What the evidence says: in mice it boosted endurance only when combined with training. ^R2 Short human trials (2 to 12 weeks) showed HDL up and triglycerides down. ^{R3, R4, R5} No human data on performance, muscle or fat loss in healthy people.

Biggest risks: the developer stopped all work after "serious toxicities" in pre-clinical studies, and WADA issued a rare health warning. ^R6 In one mouse model it drove aggressive stomach tumors after a carcinogen. ^R7

Rating


Human Human evidence	Limited: 3 short lipid trials, n = 18 to 268 ^{R3, R4, R5}
Animal Animal / lab evidence	Mouse endurance with training ^R2; tumor promotion in a mouse model ^R7
Regulatory	Never approved; not on FDA's 503A or 503B bulk-substance category lists and not on FDA's compounding safety-risk page · Prohibited at all times, WADA S4.4.1 ^{R8, R9, R10, R11}
Established human dose	None. Study details lists what studies used

Evidence verdict: Endurance / 'exercise mimetic' in people: No human data · HDL / lipid changes: Limited (short phase 1/2 trials) · Long-term safety: Serious concern (development stopped over animal toxicity)

This page reports what studies used. It is not dosing advice.

Legend: HUMAN data · ANIMAL / LAB data · UNKNOWN · UNVERIFIED: not yet confirmed against a primary source

About the evidence: the human trials were short and measured blood lipids only. The cancer concern comes from animal work; the original long-term rodent reports were never published in peer-reviewed journals. ^R6

What is it?

GW501516 (also GW1516, "cardarine", "endurobol") turns on PPAR-delta, a switch for fat burning in muscle. ^R1 It was famous after a 2008 mouse paper called it an "exercise mimetic". ^R2 Related pages: AICAR, SLU-PP-332, MOTS-c, SR9009.

Does it work?

Animal Mice: combined with training, it increased oxidative muscle fibers and running endurance; in the same paper, AICAR alone raised endurance in sedentary mice. ^R2
Human Healthy volunteers, 2 weeks: triglyceride clearance improved; HDL changes were modest. ^R3
Human Overweight men, 2 weeks (n = 18): lower liver fat, triglycerides and LDL vs placebo. ^R4
Human Low-HDL patients, 12 weeks (n = 268): HDL up to +16.9%, triglycerides −16.9%. ^R5
Unknown Endurance, muscle or body-composition effects in people: no data.

Is it safe?

Caution GSK ended development after toxicities in pre-clinical (animal) studies; WADA warned athletes in 2013. ^R6 UNVERIFIED the widely repeated claim of "cancers in multiple organs at all doses": the rodent data were not published, so we could not confirm details.
Animal In a carcinogen-primed mouse model, it caused fast-spreading stomach cancers. ^R7
Human The short human trials did not report serious harms, but they were too short to detect cancer risk. ^R5

Gray-market vials and capsules: extra risks

A gray-market vial has no quality control and no guarantee of identity, strength or sterility. We test retail vials blind under the Open Peptide Standard; see /tests/. A passing test covers one batch on one date and does not mean the compound is safe.

Is it legal?

US: never approved; not a dietary supplement ingredient; not on FDA's 503A or 503B bulk-substance category lists and not on FDA's compounding safety-risk page. ^{R9, R10, R11}
Sport: prohibited at all times under WADA S4.4.1; testing finds it in urine and hair. ^{R8, R1}

Study details

These are amounts researchers used, not recommendations.

Study	People / model	Route	Amount used	Follow-up	Reported	Citation
Healthy volunteers 2007	24 adults	Oral	2.5 or 10 mg/day	2 weeks	Triglyceride clearance better; HDL modest	PMID 17110604
Overweight men 2008	18 men	Oral	10 mg/day	2 weeks	Liver fat, TG, LDL down	PMID 18024853
Low HDL 2012	268 adults	Oral	2.5, 5 or 10 mg/day	12 weeks	HDL up to +16.9%	PMID 22814748
Mouse endurance 2008	Mice	Oral	Not applicable	4 to 5 weeks	Endurance up with training	PMID 18674809

Full reference list (PubMed, CT.gov, FDA and WADA checked Oct 26, 2026)

^R1 Kintz P, et al. Drug Test Anal. 2020. PMID 32298044
^R2 Narkar VA, et al. Cell. 2008. PMID 18674809
^R3 Sprecher DL, et al. Arterioscler Thromb Vasc Biol. 2007. PMID 17110604
^R4 Risérus U, et al. Diabetes. 2008. PMID 18024853
^R5 Olson EJ, et al. Arterioscler Thromb Vasc Biol. 2012. PMID 22814748
^R6 WADA, Alert: GW501516, letter to all anti-doping organizations, Montreal, Mar 21, 2013 (copy hosted by FIA, checked Oct 26, 2026). https://www.fia.com/sites/default/files/basicpage/file/13-03-21_ALERT%20-%20GW501516.pdf
^R7 Pollock CB, et al. PPAR Res. 2010. PMID 21318167
^R8 WADA. The 2026 Prohibited List, S4.4.1 Metabolic modulators. https://www.wada-ama.org/sites/default/files/2025-09/2026list_en_final_clean_september_2025.pdf
^R9 FDA, 503A bulk drug substances categories list (updated May 14, 2026). https://www.fda.gov/media/94155/download
^R10 FDA, 503B bulk drug substances categories list (updated Mar 21, 2025). https://www.fda.gov/media/94164/download
^R11 FDA, Certain bulk drug substances for use in compounding that may present significant safety risks (content current Apr 22, 2026). https://www.fda.gov/drugs/human-drug-compounding/certain-bulk-drug-substances-use-compounding-may-present-significant-safety-risks

Disclaimer

This page is for education and harm reduction, not medical advice or a recommendation to use Cardarine (GW501516). If you are considering a gray-market product, talk to a clinician you trust first, especially if you have or have had cancer, liver disease, are pregnant, or are a tested athlete. Report problems to FDA MedWatch (https://www.fda.gov/safety/medwatch).