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Cardarine (GW501516, GW-501516) — PPARδ agonist 'exercise mimetic'
An abandoned PPARδ agonist 'exercise mimetic' that was NEVER approved — development was halted when long-term animal studies found tumors across multiple organs. There are NO human efficacy trials; the headline endurance result is from mice on a treadmill (Narkar 2008). The only human data is a tiny 2-week lipid/HDL study. It is banned by the World Anti-Doping Agency as a gene-doping agent and is sold only as an unregulated grey-market research chemical. The cancer signal — not the endurance hype — is the real story.
Research compound — not a dietary supplement
Cardarine (GW501516) is a research compound, not a regulated dietary supplement. It is sold for research or off-label use. The evidence below is largely preclinical (animal and in-vitro) or early-stage, so no evidence score is assigned. This page is provided for transparency and education — it is not a recommendation to use. Consult a qualified healthcare provider, and be aware that purity, dosing, and legal status vary by jurisdiction.
What the evidence says
Most Cardarine (GW501516) studies are mechanism or observational rather than RCTs that measure a clinical effect — keep findings provisional.
Most evidence is from medium-quality randomised trials published 2004–2019.
Based on 9 studies · 4 RCTs
Confidence
Moderate confidenceBy outcome
Cardarine's endurance reputation rests entirely on a single mouse treadmill study, with no human efficacy trials of any kind and only a tiny 2-week human lipid study. Clinical development was abandoned over tumors across multiple organs in long-term animal toxicology, and it is a WADA-banned, grey-market-only research chemical — the cancer signal, not the endurance hype, defines the verdict, so it scores low.
Cardarine (GW501516, also 'GW-501516', 'GW1516' or the bodybuilding-forum name 'Endurobol') is a synthetic agonist of peroxisome proliferator-activated receptor delta (PPARδ/β), a nuclear receptor that drives fatty-acid oxidation and a shift toward oxidative ('slow-twitch') muscle fibres.
It was developed in the late 1990s/2000s by Ligand Pharmaceuticals and GlaxoSmithKline as a candidate for dyslipidaemia and metabolic syndrome.
The reason it is famous has nothing to do with that program: a 2008 Cell paper by Narkar et al. showed that combining the PPARδ agonist with exercise — and the AMPK agonist AICAR even without exercise — increased oxidative myofibres and treadmill running endurance in MICE, and framed the AMPK–PPARδ axis as a druggable 'exercise mimetic'.
That single ANIMAL result is the entire basis for cardarine's reputation as an endurance enhancer; there has never been a human efficacy trial of athletic performance, endurance, or fat loss.
The only published human data is a small 2-week randomised study in 24 healthy, sedentary, hospitalised volunteers (Sprecher et al. 2007) that measured lipids — it raised HDL cholesterol and improved post-fat-feeding triglyceride clearance, a pharmacology/biomarker signal, not a demonstrated clinical benefit.
Here is the load-bearing fact, and it is the reason this entry scores LOW: clinical development of GW501516 was ABANDONED because long-term rodent toxicology found it caused tumours across multiple organs.
The carcinogenicity signal is mechanistically coherent — PPARδ activation by GW501516 enhances colitis-associated colorectal cancer in mice (Zhou et al. 2019) and stimulates the proliferation of human breast and prostate cancer cell lines and tumour angiogenesis in vitro (Stephen et al. 2004).
On top of the cancer concern, GW501516 has been on the World Anti-Doping Agency prohibited list since 2009 as a gene-doping/metabolic-modulator agent, with validated urine assays for routine doping control (Thevis et al. 2010); athletes have been sanctioned for it.
It is not an approved drug anywhere, not a lawful dietary-supplement ingredient, and the material sold online is an unregulated grey-market research chemical with no identity, purity, or sterility guarantee — frequently mislabelled and contaminated.
The honest summary: an intriguing rodent endurance story, no human efficacy evidence, a development program killed by multi-organ cancer in animals, a doping ban, and grey-market-only sourcing. The cancer risk is the headline.
GW501516 is a high-affinity selective agonist of peroxisome proliferator-activated receptor delta (PPARδ/β), a nuclear receptor that drives the transcription of genes for fatty-acid uptake, β-oxidation, and oxidative metabolism in muscle and liver.
In mice, PPARδ activation upregulates fatty-acid oxidation (CPT1, CD36, ABCA1) and increases oxidative 'slow-twitch' myofibres — the proposed route to raising running endurance and shifting fuel use from carbohydrate to fat. Demonstrated in rodents and cell systems, not in humans.
The same PPARδ activation that drives oxidative metabolism also promotes cell proliferation and tumour angiogenesis. Long-term animal toxicology found tumours across multiple organs — the reason development was halted — and GW501516 enhances colorectal cancer in mice and the growth of human cancer cell lines.
How Cardarine (GW501516) works — from molecular targets to health outcomes. Click an edge to see supporting research.This visualization is in beta — pathways are being refined and expanded.
Avoid — development was halted over cancer in animals, there is no human efficacy evidence, and no quality-controlled product exists.
Avoid absolutely — WADA-prohibited since 2009; validated urine assays detect it and athletes have been sanctioned.
Avoid entirely — unstudied in humans and carcinogenic in animals.
There are no meaningful human drug-interaction data. The compound was never developed past early trials, so interactions are uncharacterised.
Stacking PPAR-active compounds (e.g. fibrates) has not been studied with GW501516; additive metabolic or hepatic effects are theoretically possible and unpredictable.
Tip: There is no mitigation — long-term animal toxicology found tumours across multiple organs, which ended development. The human cancer risk is unquantified but is the defining concern. Human frequency is unquantified — carcinogenicity comes from animal studies that ended development; treat as a serious unknown, not a measured rate.
Tip: Grey-market material has no identity/purity/sterility guarantees; cardarine products are frequently mislabelled or contaminated.
Cardarine (GW501516) has an evidence score of 3/10 — emerging evidence based on 9 indexed studies. An abandoned PPARδ agonist 'exercise mimetic' that was NEVER approved — development was halted when long-term animal studies found tumors across multiple organs. There are NO human efficacy trials; the headline endurance result is from mice on a treadmill (Narkar 2008). The only human data is a tiny 2-week lipid/HDL study. It is banned by the World Anti-Doping Agency as a gene-doping agent and is sold only as an unregulated grey-market research chemical. The cancer signal — not the endurance hype — is the real story. Representative study: PMID 17110604.
The commonly studied dose of Cardarine (GW501516) is No legitimate or recommended dose — cardarine is an unapproved grey-market research chemical whose development was halted over cancer in animals, and which is banned in sport. We do NOT provide a dosing protocol. The only published human exposure is a 2-week 2.5–10 mg lipid study in a hospital setting; that does not constitute a recommended regimen.. Individual needs vary — start at the lower end of the range and adjust based on how you respond.
Timing is flexible for Cardarine (GW501516) — consistent daily use matters more than the time of day. There is no validated or endorsed human dosing schedule.
Cardarine (GW501516) should be used with caution — talk to a healthcare provider before taking it. The most commonly reported side effects are cancer risk (animal multi-organ tumours), harm from an unregulated, impure product. Use caution if any of these apply to you: Anyone — development was abandoned over tumours across multiple organs in long-term animal studies; Not an approved medicine and not a regulated dietary supplement — unregulated grey-market research chemical; do not self-source; Competitive athletes — banned by WADA since 2009; will trigger an anti-doping violation.
Caffeine
Likely helpsBlocks adenosine receptors to boost alertness, reaction time, and endurance — one of the most proven ergogenic aids.
CoQ10
Likely helpsA lipid-soluble antioxidant central to mitochondrial energy production, with the strongest trial support for fertility/IVF outcomes and heart failure.
Berberine
Likely helpsActivates AMPK to regulate blood sugar, improve insulin sensitivity, and support lipid metabolism — comparable to metformin in some trials.
Sodium Bicarbonate
Likely helpsProven ergogenic aid that buffers lactic acid, extending high-intensity exercise capacity by 1-3%.
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Reviewed by Dr. Baher Al Hakim · Last reviewed June 2026 · evidence from 9 studies · how we score · editorial policy
This information is for educational purposes only. It is not a substitute for professional medical advice. Always consult a qualified healthcare provider before starting, stopping, or changing any supplement or medication.
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