A PPARδ agonist whose pharmaceutical sponsor walked away from Phase 2 development around 2007–2008 because of multi-organ rodent tumors at clinically relevant exposures. WADA issued an unprecedented compound-specific public alert on 21 March 2013.
Cardarine's safety record is dispositive, not theoretical. The entity with the strongest financial incentive to sell GW501516 — GlaxoSmithKline — looked at its own 2-year rodent toxicology data and chose to abandon a billion-dollar Phase 2 program rather than carry the liability into humans. Any framing of Cardarine as "discontinued for business reasons" or "pulled because of misuse" inverts the actual record. GSK terminated this molecule because it produced cancer in animals at multiple organ sites, in both sexes, in a dose-dependent manner.
The regulatory anchors are: GSK / Ligand discontinuation around 2007–2008 after long-term rodent carcinogenicity studies revealed dose-dependent tumors in multiple organ systems; WADA Prohibited List inclusion since 2009 (currently S4.5 Metabolic Modulators, prohibited at all times); a rare WADA Public Health Alert on 21 March 2013 — a compound-specific advisory citing "serious toxicities discovered in pre-clinical studies"; downstream advisories from USADA and Sport Integrity Australia. Mechanistic corroboration: Beyaz et al. Nature 2016 (PMID 26935695) showed PPARδ signaling permits Apc-loss tumor formation in intestinal progenitor cells; Qian et al. 2025 (PMID 39993702) showed PPARδ-driven CD47 upregulation enables tumor immune escape.
If you decide to use Cardarine anyway, do so with the carcinogenicity record fully visible. This guide doesn't endorse use.
Cardarine (also GW501516, GW1516, Endurobol) is a synthetic small-molecule PPARδ (peroxisome proliferator-activated receptor delta) agonist. Not a peptide and not a SARM, despite living in peptide-adjacent vendor catalogs and being commonly stacked with SARMs in gray-market practice.
It was co-developed by GlaxoSmithKline and Ligand Pharmaceuticals in the late 1990s and early 2000s, with the original therapeutic rationale being dyslipidemia and metabolic syndrome (raise HDL, lower triglycerides via PPARδ). The program reached Phase 2 trials before GSK discontinued it around 2007–2008 after long-term rodent carcinogenicity findings. No INN was ever assigned — the molecule never advanced far enough. Pelton 2006 (Curr Opin Investig Drugs, PMID 16625823) captures the program at peak development just before the carcinogenicity disclosures.
Names: GW501516 and GW1516 are used interchangeably (WADA / doping-control literature prefers "GW1516"). Cardarine and Endurobol are trivial / market names.
The mechanism is real and reproducible. GW501516 is a high-affinity, selective PPARδ agonist (selective vs PPARα and PPARγ). PPARδ activation drives transcription of fatty-acid oxidation genes, mitochondrial biogenesis genes, and a fiber-type shift toward type I (oxidative, slow-twitch) muscle. The foundational paper showing transgenic muscle-specific activated PPARδ doubled running endurance in mice is Wang 2004 (PLoS Biol, PMID 15328533); GW501516 + AMPK activation acted as a "pharmacological exercise mimetic" in untrained mice in Narkar & Evans 2008 (Cell, PMID 18674809). Metabolomic confirmation came from Chen 2015 (PMID 25943561).
The endurance phenotype is biologically real. The problem isn't the on-target effect — it's the off-target oncology. Independent mechanistic corroboration: Beyaz et al. Nature 2016 (PMID 26935695) showed PPARδ signaling enables Apc-loss tumor formation in intestinal progenitor cells, providing direct mechanistic plausibility for GI tumor risk. Qian et al. 2025 (PMID 39993702) showed PPARδ-driven CD47 upregulation enables tumor immune escape — a further oncology mechanism.
The GSK rodent toxicology dossier itself was never published as a primary research paper (IND-stage tox is rarely published). The publicly available record is captured in WADA's 2013 advisory and downstream regulatory communications.
Build your protocol, log every dose, monitor your body's response, and get reminders so you never miss a dose.
Start Tracking FreeA small number of Phase 1 / Phase 2 lipid trials were conducted before the long-term tumor disclosures or were terminated early. All are ≤12 weeks; none address the cancer-latency question.
| Study | Population | Duration | Result |
|---|---|---|---|
| Sprecher 2007 (PMID 17110604) | Healthy subjects | Short | Lipid effects characterized |
| Risérus 2008 (PMID 18024853) | Moderately obese men | 2 weeks | 10 mg/d; HDL effects |
| Ooi 2011 (PMID 21816786) | Dyslipidemic central obesity | Short | Lipoprotein metabolism mechanism |
| Olson 2012 (PMID 22814748) | Low-HDL | 12 weeks | HDL increase; secondary endpoints |
No long-term human safety data exists. The cancer-latency question is unanswered in humans — and given the rodent multi-organ tumor signal at clinically relevant exposures, that gap matters.
Doping detection: routine controls since 2009 (Thevis 2010 PMID 19946680); urinary metabolites detectable 20–40 days post-administration (Sobolevsky 2012 PMID 22977012; Ishii 2021 PMID 33319421); hair detection (Kintz 2020 PMID 32298044); combined GW1516 + ostarine cases where not all subjects claimed knowing co-administration (Kintz 2021 PMID 34678947); transmission case report (Breuer 2024 PMID 38704758).
StackTrax doesn't endorse Cardarine use. The dosing below is community / forum convention.
| Parameter | Common Range |
|---|---|
| Dose | 10–20 mg/day oral |
| Cycle length | 4–8 weeks (community); GSK Phase 2 dosed up to 12 weeks |
| Route | Oral capsule / liquid |
| Half-life | ~24 hr |
Harm-reduction rules for anyone who proceeds: shortest possible exposure (Cardarine's rodent tumors emerged in long-term 2-year studies — short cycles plausibly reduce risk, but don't normalize chronic use); don't stack with SARMs (the published case literature documents combined use and amplified hepatic / oncology risk); don't use during cancer-screening lapses (get age-appropriate screens current first); recognize the asymmetry — short-term subjective wellness is not safety data, and long-latency cancer risk is asymmetric in time.
Pre-filled with a typical Cardarine (GW501516) setup. Edit any field — the draw updates live.
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Acute community reports: mild GI effects (occasional nausea), paradoxical fatigue early in cycle despite the endurance framing, headache.
Lipids: HDL increase (the original therapeutic rationale), triglyceride decrease. These lipid effects are real but don't offset the cancer concern over time.
The dominant concern is cancer-latency risk. Multi-organ rodent carcinogenicity at clinically relevant exposures (GSK 2007–2008 disclosures, WADA 2013 advisory). Mechanistic corroboration in independent literature (Beyaz 2016, Qian 2025). No long-term human safety data. Cancer effects have long latency — the absence of acute symptoms during use isn't informative about the actual risk.
Seladelpar (MBX-8025) — a different PPARδ agonist that did reach approval (FDA 2024, for primary biliary cholangitis). Seladelpar is not Cardarine, and seladelpar's approval doesn't retroactively rehabilitate GW501516. Different molecule, different exposure profile, different indication.
PPARγ agonists (TZDs — rosiglitazone, pioglitazone) — different receptor subtype, different metabolic effects.
Fibrates (PPARα agonists) — different receptor subtype.
SARMs (RAD-140, LGD-4033, etc.) — androgen receptor modulators, completely different target. Common stacking partners but mechanistically unrelated.
SR9009 — Rev-erbα agonist, completely different target. Vendor framing of "SR9009 = safer Cardarine" is unsupported.
SLU-PP-332 — ERRβ/γ agonist; another exercise-mimetic class candidate.
AICAR — AMPK activator (different mechanism).
Cardarine (GW501516) is a research peptide not approved by the FDA for human use. It is sold only as a research chemical, and StackTrax does not endorse or facilitate personal use.
Quality varies enormously among research-chemical suppliers. At minimum, look for:
StackTrax’s preferred partner NextGen Peptides does not currently carry Cardarine (GW501516)in their catalog, which is why you don’t see a direct purchase link here. Other major research-chemical suppliers carry it; we don’t specifically recommend one for this compound.
Build your protocol, log every dose, monitor your body's response, and get reminders so you never miss a dose.
Start Tracking FreeIn rodents, yes — dose-dependent multi-organ tumors at clinically relevant exposures. GlaxoSmithKline / Ligand discontinued the Phase 2 program around 2007 to 2008 after long-term rodent carcinogenicity studies revealed tumors in multiple organ systems, in both sexes. WADA issued an unprecedented compound-specific public health alert on 21 March 2013 citing "serious toxicities discovered in pre-clinical studies." Mechanistic corroboration: Beyaz 2016 (PMID 26935695) showed PPARdelta signaling permits Apc-loss tumor formation in intestinal progenitor cells. No long-term human safety data exists, and cancer effects have long latency — the absence of acute symptoms during use is not informative about actual risk.
No. GW501516 was never approved by the FDA or EMA — no NDA was ever filed. GSK / Ligand abandoned the billion-dollar Phase 2 program around 2007 to 2008 after the rodent carcinogenicity findings, and no INN was ever assigned. Sold gray-market as a research chemical. WADA prohibits it at all times under S4.5 (Metabolic Modulators).
No. Cardarine (GW501516, GW1516, Endurobol) is a synthetic small-molecule PPARdelta (peroxisome proliferator-activated receptor delta) agonist. It is not a peptide and not a SARM, despite living in peptide-adjacent vendor catalogs and being commonly stacked with SARMs in gray-market practice. The mechanism is nuclear-receptor agonism at PPARdelta, completely unrelated to androgen receptor modulation.
Community ranges are 10 to 20 mg/day oral, in 4 to 8 week cycles. The half-life is roughly 24 hours, which supports once-daily dosing. GSK Phase 2 dosed up to 12 weeks before the program was abandoned. StackTrax doesn't endorse Cardarine use — the rodent multi-organ tumor signal at clinically relevant exposures is dispositive, and no long-term human safety data exists.
GW501516 is a high-affinity, selective PPARdelta agonist (selective vs PPARalpha and PPARgamma). PPARdelta activation drives transcription of fatty-acid oxidation genes, mitochondrial biogenesis genes, and a fiber-type shift toward type I (oxidative, slow-twitch) muscle. Wang 2004 (PMID 15328533) showed transgenic muscle-specific activated PPARdelta doubled running endurance in mice; Narkar & Evans 2008 (PMID 18674809) showed GW501516 plus AMPK activation acted as a pharmacological exercise mimetic in untrained mice. The endurance phenotype is biologically real — the problem is the off-target oncology.
Neither has long-term human safety data, and the vendor framing of "SR9009 = safer Cardarine" is unsupported. Cardarine has documented multi-organ rodent carcinogenicity that GSK pulled the program over. SR9009 has not had an equivalent long-term tox study done — the absence of equivalent data reflects the absence of studies, not evidence of safety. They target completely different receptors (PPARdelta vs Rev-erbalpha) and are mechanistically unrelated.
Yes — at all times since 2009, currently under S4.5 (Metabolic Modulators). GW1516 and its sulfoxide and sulfone metabolites are routinely detected in human urine for 20 to 40 days post-administration (Sobolevsky 2012 PMID 22977012; Thevis 2010 PMID 19946680). Hair detection is also possible (Kintz 2020 PMID 32298044). WADA issued a rare compound-specific Public Health Alert on 21 March 2013, and downstream advisories followed from USADA and Sport Integrity Australia.
Disclaimer: This guide is for educational and informational purposes only and is not intended as medical advice, diagnosis, or treatment. The compounds discussed are not FDA approved for human use. Always consult a qualified healthcare provider before starting any new supplement or peptide protocol. StackTrax does not sell peptides or supplements directly — purchase links go to third-party vendors. StackTrax is not responsible for the products, quality, or business practices of any third-party vendor. This page contains affiliate links — StackTrax may earn a commission on purchases at no extra cost to you.
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StackTrax guides cover peptides and compounds that are not FDA-approved for the uses discussed. The dosing, reconstitution, and safety information is compiled from published research and community protocols for educational purposes only.
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