Cardarine (GW501516, often written GW 50156) is not a SARM. It is a PPAR-delta agonist that GlaxoSmithKline tested in short human trials for blood-fat problems, then dropped in 2006 when long-term studies in rats and mice found cancers in many organs (Health Canada 2013; Toxicologist 2009). In people, it raised HDL and lowered triglycerides over 2 to 12 weeks, but no human trial has measured fat loss or endurance (Olson 2012). It was never approved, and WADA took the rare step of warning athletes about it directly (WADA 2013).
Below: what cardarine is, every human and animal study, what it does and does not do, the cancer findings and whether cardarine is safe, the doses studied, its legal status, and links to all of our cardarine guides.
What is cardarine (GW501516)?
Cardarine switches on PPAR-delta, a receptor that controls how muscles burn fat. It does not act on the androgen receptor, so it is not a SARM, even though it is sold next to them; WADA lists it as a metabolic modulator, not with the anabolic agents (WADA 2026). The same molecule is called GW501516, GW-501516, GW1516, endurobol and GSK-516 (PubChem CID 9803963). “GW 50156” is a common misspelling of GW501516.
In adult mice, a PPAR-delta agonist combined with exercise training increased oxidative muscle fibers and running endurance (Narkar 2008). That mouse result is where the “endurobol” name and the endurance claims come from. In people, the measured effects are on blood fats, liver fat and insulin.
Cardarine research at a glance
| Study | Who | Dose and length | What it found | Evidence |
|---|---|---|---|---|
| Sprecher 2007 | 24 healthy, sedentary volunteers | 2.5 or 10 mg/day vs placebo, 2 weeks | HDL rose on both doses while it fell 11.5% on placebo; triglycerides trended down. The first report of a PPAR-delta agonist given to humans. | Trial |
| Risérus 2008 | 18 moderately overweight men (6 per group) | 10 mg/day, 2 weeks | Triglycerides −30%, apoB −26%, LDL −23%, insulin −11%, liver fat −20%; HDL unchanged; more fat burned after a meal. | Randomized trial |
| Ooi 2011 | 13 men with central obesity and abnormal lipids | 2.5 mg/day, 6-week crossover | Triglycerides, apoB and VLDL fell; HDL rose. | Randomized trial |
| Olson 2012 | 268 adults with low HDL | 2.5, 5 or 10 mg/day vs placebo, 12 weeks | HDL up to +16.9%; LDL −7.3%; triglycerides −16.9%; apoB −14.9%; free fatty acids −19.4%. | Trial |
| GSK 2-year rat study (Toxicologist 2009) | Rats | 3–40 mg/kg/day, 104 weeks | Drug-related tumors in many tissues at all doses; females on every dose died earlier, often from uterine cancer. | Animal |
| GSK 2-year mouse study (Toxicologist 2009) | Mice | 10–80 mg/kg/day, 104 weeks | Liver cancers from 30 mg/kg and stomach cancers at all doses; survival fell from 30 mg/kg. | Animal |
| Gupta 2004 | Mice prone to intestinal polyps | Not applicable | More and larger polyps (five times more over 2 mm). | Animal |
| Narkar 2008 | Adult mice | With exercise training | More oxidative muscle fibers and longer running endurance. | Animal |
The longest human trial lasted 12 weeks. No human study has looked at cancer, body fat, muscle or performance as an outcome. Compare cardarine with other compounds in the SARMs database.
Does cardarine burn fat?
Not established in people. Over 2 weeks it increased fat burning after a test meal and lowered liver fat by 20% (Risérus 2008), but no human trial has measured body-fat loss or weight loss as an outcome (Olson 2012). The fat-loss reputation comes from mice and from user reports. Our cardarine before and after page collects those reports, including the “1 month” results people search for, next to this evidence; best SARMs for cutting compares the options.
Can you use cardarine without losing muscle?
There are no human data on muscle with cardarine: none of the four trials measured it. It does not act on the androgen receptor, so it is not expected to build muscle the way SARMs are claimed to.
Endurance
Shown only in mice. A PPAR-delta agonist combined with exercise training increased oxidative muscle fibers and running endurance (Narkar 2008). No human study has tested endurance or performance. See best SARMs for endurance and the related PPAR-delta drug GW0742.
Cholesterol, triglycerides and insulin
This is what was actually measured. Over 12 weeks, HDL rose by up to 16.9% (on 10 mg) and triglycerides fell 16.9% (Olson 2012); in a 2-week study, triglycerides fell 30%, LDL 23% and fasting insulin 11% (Risérus 2008). GSK was developing it as a drug for these lipid problems before the animal findings stopped it (Health Canada 2013).
Does cardarine cause cancer?
No human data show this, because long-term human studies were never done. The animal data are why the drug was stopped:
- In GSK’s 2-year rat study (3–40 mg/kg/day), drug-related tumors appeared in many tissues at all doses, including liver, bladder, thyroid, stomach, skin, testes, ovary and uterus. Females on every dose died earlier, often from uterine cancer (Toxicologist 2009).
- In the 2-year mouse study (10–80 mg/kg/day), liver cancers appeared from 30 mg/kg and stomach cancers at every dose; survival fell from 30 mg/kg (Toxicologist 2009).
- In mice prone to intestinal polyps, GW501516 made polyps more numerous and larger (Gupta 2004).
GSK ended development in 2006 after these toxicities, “including a variety of cancers”, were found; its 2013 letter, published by Health Canada, says long-term effects in humans are unknown (Health Canada 2013). WADA said its side effects were so serious that it warned athletes directly, and that clinical approval “has not, and will not be given” (WADA 2013). Animal doses per kilogram do not translate directly to human doses, which is exactly why the size of the human risk is unknown. More: do SARMs cause cancer?
Is cardarine safe?
Its safety for regular use has never been established. What is known:
| Risk | What was found | Evidence |
|---|---|---|
| Cancer in rats and mice | Tumors in many organs in 2-year studies, some at every dose tested (Toxicologist 2009). | Animal |
| Faster polyp growth | More and larger intestinal polyps in susceptible mice (Gupta 2004). | Animal |
| Unknown long-term effects | Development stopped; WADA warned athletes in 2013 (Health Canada 2013; WADA 2013). | Regulator warning |
| Liver damage and muscle breakdown | With ostarine: ALT up to 922 U/L, AST up to 2,558 U/L, CPK up to 86,435 U/L in a 43-year-old man; recovered in about 6 weeks (Kintz 2021). | Case report |
| Hormone problems from contaminated products | Breast growth and low testosterone after supplements containing cardarine, RAD-140 and MK-677 plus undeclared hormones (Chong 2024). | Case report |
| Wrong product | GW501516 turned up in products sold as SARMs: 39% of 44 such products contained a different unapproved drug (Van Wagoner 2017). | Lab analysis |
The short human trials (up to 12 weeks) reported on blood fats, liver fat and insulin (Olson 2012; Risérus 2008); they were far too short to show a cancer risk. There is no evidence-based way to make a cardarine cycle “safe”, because no one has measured the risk in people. More: side effects of SARMs and related compounds and liver effects.
Can women take cardarine?
No study has looked at cardarine for fat loss in women. In the rat study, females on every dose died earlier, often from uterine cancer (Toxicologist 2009). See best SARMs for women for the wider evidence.
Testosterone, suppression and PCT
Cardarine is not a hormone and does not act on the androgen receptor, so it is not expected to lower testosterone. The human trials did not measure testosterone, so there are no human data either way (WADA 2026). On its own it is not a reason for PCT; when it is stacked with a SARM, the SARM’s suppression is what matters.
Bloodwork
Lipids, liver fat and insulin changed in the human trials, and CK and liver enzymes were very high in the case report:
- Lipid panel (HDL, LDL, triglycerides)
- ALT and AST (liver enzymes)
- Fasting glucose and insulin
- CK (creatine kinase)
How to read them: bloodwork guide.
Cardarine dosage: what studies used
Human trials used 2.5, 5 or 10 mg a day for 2 to 12 weeks, to study blood fats (Sprecher 2007; Risérus 2008; Ooi 2011; Olson 2012). No study tested a dose for fat loss or endurance, and none lasted longer than 12 weeks. Retail products are sold by label strength; SwissChems, for example, sells cardarine as 10 mg capsules, the highest dose used in the trials. Our cardarine dosage page sets trial doses next to what users report.
Cardarine half-life
No published human study gives a plasma half-life. In an anti-doping study, unchanged GW501516 showed up in urine only briefly, while its sulfone breakdown product was found for up to 40 days after one 15 mg dose (Sobolevsky 2012). Half-life figures quoted online do not come from a published human study. More in cardarine half-life.
Is cardarine legal?
- United States: not approved. A December 2025 FDA warning letter called products sold as “Cardarine GW501516” unapproved new drugs (FDA warning letter, 2025).
- Canada: not approved for use in humans; Health Canada published GSK’s 2013 warning not to use it under any circumstances (Health Canada 2013).
- Australia: Schedule 10, for substances so dangerous to health that their supply and use are prohibited (Poisons Standard 2026).
- Germany: the Anti-Doping Act’s annex lists “GW501516, synonym GW1516, Cardarin, Endurobol” (AntiDopG annex); trading in it for doping in sport, or possessing a non-small quantity for that purpose, is banned (AntiDopG §2).
Buying it on Amazon or in mainstream stores: can you buy SARMs, MK-677 and cardarine on Amazon? Country by country: are SARMs legal?
Cardarine in sport and drug tests
WADA has banned GW501516 since 2009 under S4.4 (metabolic modulators), at all times (Thevis 2010; WADA 2026). Its sulfone metabolite stayed detectable in urine for up to 40 days after a single 15 mg dose (Sobolevsky 2012), and it has been found in hair (Kintz 2020). See drug tests and WADA.
Cardarine vs SARMs and SR9009
| Compound | Target | Human evidence | Main concern |
|---|---|---|---|
| Cardarine | PPAR-delta | Four short lipid trials (2–12 weeks) | Cancers in 2-year rat and mouse studies (Toxicologist 2009) |
| SR9009 (stenabolic) | REV-ERB (body clock) | None (ClinicalTrials.gov) | Two case reports of serious liver injury (Shams Bin Shaheen 2026) |
| Ostarine | Androgen receptor | Phase 2 and Phase 3 trials | Lower testosterone and HDL; liver injury reports (Dalton 2011) |
Head-to-head: cardarine vs ostarine, SR9009 vs cardarine, or use the compare tool.
Cardarine stacks
No study has tested cardarine with any other compound. The detailed case reports involve combinations: ostarine plus cardarine with severe liver injury and muscle breakdown (Kintz 2021), and cardarine with RAD-140 and MK-677 in a product that also held undeclared hormones (Chong 2024). Our stack pages: RAD-140 and cardarine and ostarine stacks (including ostarine with cardarine). Check overlapping risks with the stack checker.
Buying cardarine: is it what the label says?
Products sold as SARMs are often mislabeled: GW501516 was one of the unapproved drugs found in 39% of 44 products tested, and only 41% matched their label amount (Van Wagoner 2017). It was also among the five molecules most often found in a 2025 study of suspected illegal medicines bought as performance enhancers (Barrios 2025). Look for a lot-specific certificate of analysis and learn how to read a lab test. Our current pick is SwissChems, which publishes lot-specific lab reports; see our SwissChems review.
Bottom line
Cardarine improves blood fats over a few weeks in people, and that is all that has been measured in humans. Its fat-loss and endurance reputation comes from mice and user reports. Its developer stopped it because rats and mice given it for two years developed cancers in many organs, some at every dose, and no one knows how that translates to people. It is banned in sport, prohibited outright in Australia, and detectable for weeks. If you are weighing it up, the cancer data are the fact to start from.
Charts
| Dose studied | Who took part | Duration | What the study found | Source |
|---|---|---|---|---|
| 2.5 mg/day or 10 mg/day | Healthy volunteers, hospitalized and sedentary (n=24) | 2 weeks | Placebo-controlled HDL cholesterol rose on both doses while it fell 11.5% on placebo. Triglycerides trended down, and fat from a test meal was cleared faster. The authors call it the first report of a PPARδ agonist given to humans. | PubMed 2007 |
| 10 mg/day | Moderately overweight healthy men (6 per group; a PPARα drug and placebo were the other groups) (n=18) | 2 weeks | Randomized, double-blind, three-group parallel Triglycerides fell 30%, apoB 26%, LDL 23%, insulin 11% and liver fat 20%. HDL did not change. Fat burning after a meal rose. | PubMed 2008 |
| 2.5 mg/day | Men with central obesity and abnormal blood lipids (n=13) | 6 weeks per period | Randomized, double-blind, placebo-controlled crossover Triglycerides, apoB and VLDL fell. HDL cholesterol rose. | PubMed 2011 |
| 2.5, 5 or 10 mg/day | Adults with low HDL cholesterol (under 1.16 mmol/L) (n=268) | 12 weeks | Placebo-controlled HDL rose up to 16.9% (10 mg). LDL fell 7.3%, triglycerides 16.9%, apoB 14.9% and free fatty acids 19.4%. A second study (n=37) found fewer small LDL particles. | PubMed 2012 |
Sources: the studies linked in the table.
Source: Sarmguide compound database; Cardarine value: Detection of PPARδ agonists GW1516 and GW0742 and their metabolites in human urine (2012).
More on Cardarine
Frequently asked questions
Is cardarine a SARM?
No, a PPAR-delta agonistEvidence: Law
Cardarine (GW501516) acts on PPAR-delta, a receptor that controls fat burning, not on the androgen receptor. WADA lists it as a metabolic modulator (S4.4), not with the SARMs.
Why was cardarine discontinued?
Cancers in animal studiesEvidence: Animal
GSK stopped development in 2006 after 2-year studies in rats and mice found tumors in several organs, some at every dose tested. In 2013 WADA warned athletes directly because of these risks.
What did human studies of cardarine show?
Better blood fats, short termEvidence: Trial
Trials of 2–12 weeks looked at blood fats: over 12 weeks HDL rose by up to 16.9% (on 10 mg a day) and triglycerides fell 16.9%. In a 2-week study in 6 overweight men, triglycerides fell 30% and liver fat 20%.
Does cardarine burn fat?
Not established in peopleEvidence: Trial
It raised fat burning after a meal and lowered liver fat in a 2-week study. No human trial has measured body-fat loss or weight loss.
How long does cardarine take to work?
Blood fats changed in 2 weeksEvidence: Trial
Changes in blood fats and liver fat were seen after 2 weeks in people. No human study has measured body fat or endurance at all, so there is no timeline for those.
Does cardarine increase endurance?
Only shown in miceEvidence: Animal
In a 2008 mouse study, a PPAR-delta agonist plus exercise training increased running endurance. No human study has tested endurance or performance.
Does cardarine cause cancer?
In rats and mice; unknown in humansEvidence: Animal
Long-term human studies were never done, but in GSK's 2-year studies rats and mice developed drug-related tumors, for example in the liver, stomach, bladder, thyroid and uterus. In polyp-prone mice it made intestinal polyps larger and more numerous.
Is cardarine safe?
Not shown to be safeEvidence: Animal
Human trials lasted at most 12 weeks and only measured blood fats, liver fat and insulin, while 2-year animal studies found cancers in many organs. GSK's letter says long-term effects in humans are unknown.
Can women take cardarine for weight loss?
Not studied in womenEvidence: Limited
No study has tested cardarine for fat loss in women. In GSK's rat study, females on every dose died earlier, often from uterine cancer.
Does cardarine need PCT?
Not expected; not measuredEvidence: Limited
It is not a hormone and does not act on the androgen receptor, so it is not expected to lower testosterone. The human trials did not measure testosterone, so there are no human data either way.
What is the half-life of cardarine?
Not published for humansEvidence: Human data
No published human study gives a plasma half-life. In an anti-doping study a breakdown product was found in urine for up to 40 days after one 15 mg dose.
Is cardarine legal?
Not approved; prohibited in AustraliaEvidence: Law
The FDA calls products sold as cardarine unapproved new drugs, and Australia lists it in Schedule 10, which prohibits its supply and use. Health Canada published GSK's warning not to use it.
Is cardarine banned in sport?
Yes, banned by WADAEvidence: Law
WADA has banned it at all times since 2009 under S4.4 (metabolic modulators). Its breakdown products can be detected for weeks.
Sources
- Health Canada: GW501516 – Serious risks associated with use of unauthorized product (GSK letter, 24 May 2013)
- Rat carcinogenicity study with GW501516, a PPAR delta agonist (Geiger et al., The Toxicologist 2009, abstract 895)
- Lipid effects of peroxisome proliferator-activated receptor-δ agonist GW501516 in subjects with low high-density lipoprotein cholesterol: characteristics of metabolic syndrome
- WADA issues alert on GW501516 (21 March 2013)
- WADA: The Prohibited List (2026 List, in force from 1 January 2026)
- PubChem: GW501516 / Cardarine (CID 9803963), names and synonyms
- AMPK and PPARdelta agonists are exercise mimetics
- Activation of peroxisome proliferator-activated receptor (PPAR)delta promotes reversal of multiple metabolic abnormalities, reduces oxidative stress, and increases fatty acid oxidation in moderately obese men
- Activation of nuclear hormone receptor peroxisome proliferator-activated receptor-delta accelerates intestinal adenoma growth
- Peroxisome Proliferator-Activated Receptor Delta Agonist (PPAR- δ) and Selective Androgen Receptor Modulator (SARM) Abuse: Clinical, Analytical and Biological Data in a Case Involving a Poisonous Combination of GW1516 (Cardarine) and MK2866 (Ostarine)
- Reversible Gynecomastia and Hypogonadism Due to Usage of Commercial Performance-Enhancing Supplement Use
- Chemical Composition and Labeling of Substances Marketed as Selective Androgen Receptor Modulators and Sold via the Internet
- Triglyceride:high-density lipoprotein cholesterol effects in healthy subjects administered a peroxisome proliferator activated receptor delta agonist
- Mechanism of action of a peroxisome proliferator-activated receptor (PPAR)-delta agonist on lipoprotein metabolism in dyslipidemic subjects with central obesity
- Detection of PPARδ agonists GW1516 and GW0742 and their metabolites in human urine
- FDA Warning Letter to an online seller of products marketed as SARMs (MARCS-CMS 719257), 12 December 2025
- Therapeutic Goods (Poisons Standard—June 2026) Instrument 2026 (F2026L00633)
- Anlage zum Anti-Doping-Gesetz (AntiDopG), Germany (BGBl. 2023 I Nr. 67)
- § 2 Anti-Doping-Gesetz (AntiDopG): Unerlaubter Umgang mit Dopingmitteln (Germany)
- Characterization of two major urinary metabolites of the PPARdelta-agonist GW1516 and implementation of the drug in routine doping controls
- Testing for GW501516 (cardarine) in human hair using LC/MS-MS and confirmation by LC/HRMS
- ClinicalTrials.gov search for 'SR9009', 'SR-9009' and 'stenabolic': no studies found (checked 30 October 2026)
- Acute Liver Failure in an Adolescent Following Use of the Synthetic REV-ERB Agonist SR9009
- The selective androgen receptor modulator GTx-024 (enobosarm) improves lean body mass and physical function in healthy elderly men and postmenopausal women: results of a double-blind, placebo-controlled phase II trial
- SARMs, Metabolic Modulators and Growth Hormone Secretagogues in Suspected Illegal Medicines, Bought as Sport Performance Enhancers: A Retro- and Prospective Study Within the GEON
