# Cardarine (GW501516) Dosage Research Protocol Guide (2026)
> Research Use Only (RUO) Disclaimer: GW501516 (Cardarine) is not approved by the FDA or any regulatory authority for human use. Phase II clinical trials were terminated by GlaxoSmithKline in 2007 due to carcinogenicity findings in preclinical studies. All information below is intended strictly for scientific research purposes. Not for human consumption, therapeutic use, or self-administration. See the carcinogenicity section below — this is a critical safety consideration.
What Is Cardarine (GW501516)?
Cardarine, chemically designated GW501516 (IUPAC: {4-[({4-methyl-2-[4-(trifluoromethyl)phenyl]-1,3-thiazol-5-yl}methyl)sulfanyl]-2-methylphenoxy}acetic acid), is a synthetic PPARdelta (peroxisome proliferator-activated receptor delta, also written PPARbeta/delta) agonist developed jointly by GlaxoSmithKline (GSK) and Ligand Pharmaceuticals in the early 2000s.
Critical pharmacological distinction: GW501516 is NOT a SARM. It does not bind to the androgen receptor. It is a PPAR agonist — an entirely different class of transcription factor — and its mechanism of action, tissue targets, and research applications are fundamentally different from SARMs like RAD-140 or LGD-4033.
GW501516 was originally developed as a treatment for metabolic syndrome, dyslipidemia, and related cardiovascular risk factors. It showed promising preclinical results in improving lipid profiles and increasing fatty acid oxidation (FAO). However, Phase II clinical development was discontinued in 2007 when long-term animal safety studies revealed accelerated development of multiple tumor types across several organ systems.
Mechanism of Action: PPARdelta Pathway
PPARdelta is a nuclear receptor that, when activated by an agonist, acts as a transcription factor — it binds to PPAR response elements (PPREs) in the promoters of target genes and upregulates their transcription.
Key PPARdelta-regulated processes:
- •Fatty acid oxidation (FAO): PPARdelta upregulates genes for beta-oxidation in skeletal muscle and adipose tissue, increasing fat metabolism
- •Mitochondrial biogenesis: Activates PGC-1alpha, driving mitochondrial proliferation — similar to the adaptations of aerobic exercise training
- •Glucose metabolism: Improves insulin sensitivity in skeletal muscle by reducing lipid accumulation (lipotoxicity)
- •HDL cholesterol: Upregulates ABCA1 and ApoA-I, increasing reverse cholesterol transport and HDL levels
- •Inflammation: Has anti-inflammatory effects in macrophages via downregulation of NF-kappaB-dependent cytokines
In skeletal muscle, GW501516 produces a shift toward oxidative (type I, slow-twitch) fiber characteristics, increasing mitochondrial density and fatty acid utilization. This is why it attracted research interest for endurance capacity studies.
Pharmacokinetics
- •Oral bioavailability: High; GW501516 is orally active
- •Half-life: Approximately 16–24 hours (enables once-daily dosing in research models)
- •Metabolism: Hepatic metabolism via multiple CYP isoforms
- •Protein binding: High plasma protein binding
Dosage Protocols in Research Models
Published Preclinical and Early Clinical Data
GSK's Phase I clinical data (before trial termination) studied doses of:
- •2.5 mg/day
- •5 mg/day
- •10 mg/day
Short-term Phase I data showed improvements in HDL cholesterol, reduced LDL/non-HDL cholesterol, and reduced fasting triglycerides at these doses.
Research Protocol Dosing Reference
| Research Context | Dose Range | Frequency | Duration |
|---|---|---|---|
| Lipid metabolism studies | 5–10 mg/day | Daily (oral) | 4–8 weeks |
| Endurance/FAO research | 5–10 mg/day | Daily (oral) | 4–8 weeks |
| Metabolic syndrome models | 10–20 mg/day | Daily (oral) | 4–12 weeks |
| Animal model studies | 3–10 mg/kg | Daily | Varies |
Critical Safety Concern: Carcinogenicity
This section is mandatory reading for any researcher considering GW501516 studies.
In 2007, GSK terminated all clinical development of GW501516 after long-term rodent carcinogenicity studies revealed the compound caused rapid tumor development across multiple organ systems:
- •Liver tumors: Hepatocellular adenomas and carcinomas
- •Bladder tumors: Urothelial carcinomas
- •Skin tumors: Subcutaneous sarcomas
- •Gastric tumors: Adenocarcinomas
- •Tongue tumors
These tumors appeared at doses that were close to the pharmacologically active doses — meaning there was limited or no safety margin between efficacy and carcinogenicity. The mechanism appears to involve PPARdelta's role in promoting cell proliferation pathways in rapidly dividing epithelial cells.
Research implications:
- •Short-term (4–8 week) studies in rodents may not capture the carcinogenicity risk
- •Longer studies require rigorous histopathological monitoring
- •The WADA (World Anti-Doping Agency) banned GW501516 in 2009 due to safety concerns, explicitly warning athletes against use
- •Human studies with GW501516 are not sanctioned by any regulatory authority
The carcinogenicity concern does not negate the compound's research value for understanding PPARdelta biology, fat oxidation pathways, and mitochondrial biogenesis mechanisms. However, researchers must design studies with appropriate duration controls, histopathological endpoints, and institutional oversight.
Metabolic and Endurance Research Applications
Despite its safety profile concerns, GW501516 has contributed significantly to scientific understanding of:
Fatty Acid Oxidation Research
GW501516 is one of the most potent known PPARdelta agonists, making it a valuable tool compound for:
- •Mapping PPARdelta-responsive genes in skeletal muscle
- •Understanding the molecular basis of exercise-induced mitochondrial adaptations
- •Studying fat-glucose substrate utilization in insulin-resistant models
Lipid Profile Research
- •GW501516 produces among the most pronounced HDL increases of any pharmaceutical agent studied in humans
- •The reverse cholesterol transport mechanism (ABCA1/ApoA-I upregulation) is well-characterized via GW501516 research
- •This research informs the development of safer next-generation PPARdelta agonists
Comparative Context: Other PPAR Agonists
| Agent | PPAR Target | Clinical Status | Key Effect |
|---|---|---|---|
| GW501516 | PPARdelta | Discontinued | FAO, HDL increase |
| Rosiglitazone (Avandia) | PPARgamma | Approved (restricted) | Insulin sensitization |
| Fenofibrate | PPARalpha | Approved | Triglyceride reduction |
| Pemafibrate | PPARalpha | Approved (Japan) | Triglyceride reduction |
Monitoring Parameters for Research Protocols
- •Lipid panel: HDL, LDL, VLDL, triglycerides — the primary endpoints in most GW501516 research
- •Liver function tests: AST, ALT, GGT, bilirubin — essential given hepatic carcinogenicity risk
- •Fasting glucose and insulin: Insulin sensitivity effects assessment
- •Histopathological examination: For longer-duration studies (>8 weeks), tissue histopathology is required at study endpoint
- •Body weight and composition: FAO effects on adipose tissue mass
Conclusion
GW501516 (Cardarine) occupies a scientifically unique position: it is among the most potent and selective PPARdelta agonists available as a research tool, with well-characterized metabolic and endurance-enhancing properties via fatty acid oxidation and mitochondrial biogenesis. Its clinical development was terminated due to significant carcinogenicity concerns — a fact that researchers must weigh carefully when designing studies. For mechanistic PPARdelta research, lipid metabolism studies, or mitochondrial biology investigations, GW501516 remains a valuable pharmacological probe. All research must be conducted with appropriate institutional oversight, carcinogenicity monitoring, and duration controls.
For research purposes only. Not for human use.
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This article is for educational and research purposes only. GW501516 is not approved for human use and has significant safety concerns. Peptides.SO does not endorse or encourage the use of this compound.