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Cardarine (GW501516, GW-501516) — PPARδ agonist 'exercise mimetic'
An abandoned PPARδ agonist 'exercise mimetic' — development was halted when long-term animal studies found tumors across multiple organs. The headline endurance result is from mice on a treadmill (Narkar 2008). Small human trials have studied GW501516 and reported changes in lipid biomarkers. These findings do not establish improved exercise performance, longevity benefits or long-term safety. Animal cancer findings remain a serious concern. SupStack does not recommend self-directed cardarine use. It is banned by the World Anti-Doping Agency as a gene-doping agent and is sold 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 2004–2023.
Based on 10 studies · 4 RCTs
Confidence
Moderate confidenceBy outcome
Cardarine's endurance reputation rests entirely on a single mouse treadmill study. Small human trials have studied GW501516 and reported changes in lipid biomarkers. These findings do not establish improved exercise performance, longevity benefits or long-term safety. Animal cancer findings remain a serious concern. SupStack does not recommend self-directed cardarine use. 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 cited human studies address limited outcomes and do not establish safe performance-enhancing use.
Here is the load-bearing fact, and it is the reason its score is 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.
In 2013, WADA warned that GW501516 development had been stopped following serious preclinical toxicity findings. GW501516 is prohibited under the 2026 WADA List. SupStack does not recommend cardarine use.
The material sold online is an unregulated grey-market research chemical with no identity, purity, or sterility guarantee. The honest summary: an intriguing rodent endurance story, a development program killed by multi-organ cancer in animals, a doping ban, and grey-market-only sourcing.
Small human trials have studied GW501516 and reported changes in lipid biomarkers. These findings do not establish improved exercise performance, longevity benefits or long-term safety. Animal cancer findings remain a serious concern. SupStack does not recommend self-directed cardarine use.
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. Small human trials have studied GW501516 and reported changes in lipid biomarkers. These findings do not establish improved exercise performance, longevity benefits or long-term safety. Animal cancer findings remain a serious concern. SupStack does not recommend self-directed cardarine use.
Avoid absolutely — WADA-prohibited since 2009; validated urine assays detect it and athletes have been sanctioned.
Avoid entirely — carcinogenic in animals. Small human trials have studied GW501516 and reported changes in lipid biomarkers. These findings do not establish improved exercise performance, longevity benefits or long-term safety. Animal cancer findings remain a serious concern. SupStack does not recommend self-directed cardarine use.
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; products from unverified sources may have unreliable identity, strength or quality.
Cardarine (GW501516) has an evidence score of 3/10 — emerging evidence based on 10 indexed studies. An abandoned PPARδ agonist 'exercise mimetic' — development was halted when long-term animal studies found tumors across multiple organs. The headline endurance result is from mice on a treadmill (Narkar 2008). Small human trials have studied GW501516 and reported changes in lipid biomarkers. These findings do not establish improved exercise performance, longevity benefits or long-term safety. Animal cancer findings remain a serious concern. SupStack does not recommend self-directed cardarine use. It is banned by the World Anti-Doping Agency as a gene-doping agent and is sold as an unregulated grey-market research chemical. The cancer signal — not the endurance hype — is the real story. Representative study: PMID 17110604.
Dosing for Cardarine (GW501516): No recommended dose — cardarine is a 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. Small human trials have studied GW501516 and reported changes in lipid biomarkers. These findings do not establish improved exercise performance, longevity benefits or long-term safety. Animal cancer findings remain a serious concern. SupStack does not recommend self-directed cardarine use.
Timing is flexible for Cardarine (GW501516) — consistent daily use matters more than the time of day. There is no validated human dosing schedule.
No consumer dose of Cardarine (GW501516) is endorsed, so there is no dose at which it can be called safe. Talk to a healthcare provider before taking it. Reported side effects include animal cancer signal, harm from an unregulated, impure product. How often they occur is not established for all of them. Use caution if any of these apply to you: Anyone — development was abandoned over tumours across multiple organs in long-term animal studies; Unregulated grey-market research chemical; do not self-source; Competitive athletes — banned by WADA since 2009.
Caffeine
Probably helpsBlocks adenosine receptors to boost alertness, reaction time, and endurance — an umbrella review of 21 meta-analyses found it ergogenic for endurance, strength and power.
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. Its only head-to-head trial with metformin cited here was a 36-person pilot, which does not show it can replace metformin.
Sodium Bicarbonate
Likely helpsErgogenic aid that buffers metabolic acid. An umbrella review of meta-analyses found it improves peak anaerobic power and efforts lasting about 45 seconds to 8 minutes, on moderate to low quality evidence.
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Reviewed by Dr. Baher Al Hakim · Last reviewed June 2026 · evidence from 10 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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