metabolite is one of those subjects where the details matter more than the headlines. This page pulls together the background, the mechanisms, and the practical points readers ask about most.
Last reviewed on 2026-03-23. Where a claim depends on a specific study, the study is described rather than over-claimed.
Regulatory bodies treat GW501516 as a prohibited substance in competitive sport. The World Anti-Doping Agency added it to the prohibited list, and it falls under classes covering metabolic modulators and hormone-related agents. It is not approved by drug regulators for human use, and it is not a lawful dietary supplement. Products sold under the cardarine name may contain unlisted ingredients or different compounds. Because no approved product exists, quality and identity are not guaranteed by pharmaceutical manufacturing standards.
Cardarine is a common name for the investigational chemical GW501516, also written GW-1516. It was developed as a peroxisome proliferator-activated receptor delta agonist for metabolic conditions such as dyslipidemia. Early research focused on lipid handling and energy use in skeletal muscle and other tissues. The compound was never approved as a medicine. In public discussion, it is often grouped with performance-enhancing substances, although its receptor target differs from that of anabolic steroids or selective androgen receptor modulators. Regulatory and health authorities have issued warnings about its use.
GW501516 acts on PPARδ, a nuclear receptor that helps regulate fatty acid oxidation and energy homeostasis. In animal studies, activation of this receptor was associated with increased endurance and changes in lipid metabolism. Human trials examined effects on blood lipids and other metabolic markers, but the compound did not advance to approval. Rodent studies later reported tumors in multiple tissues at doses used in those experiments. Whether those findings translate to human risk remains uncertain, and the clinical relevance of the animal data is still debated.
Products sold as cardarine have been found to contain incorrect compounds, variable amounts, or no active ingredient at all. Independent testing is required to verify identity and purity. Common analytical approaches include high-performance liquid chromatography, mass spectrometry, and nuclear magnetic resonance for structural confirmation. These methods can distinguish GW501516 from related PPAR agonists and from unrelated steroids. For regulators and researchers, such verification is central to interpreting both biological results and adverse event reports.
Cardarine is prohibited in competitive sport under the World Anti-Doping Agency code, where it is classified as a metabolic modulator. It is not approved as a prescription medicine in the United States, European Union, or other major markets. Regulatory action has focused on its presence in sports and in products marketed as research chemicals. Because it has no accepted medical indication, supply is often unregulated. This status creates legal and safety uncertainties for anyone who encounters the substance.
Anti-doping laboratories detect GW501516 and its metabolites using liquid chromatography-tandem mass spectrometry. Urine is the most common matrix, though blood and dried blood spots may also be used in some programs. Detection depends on factors such as dose, timing, metabolism, and the sensitivity of the assay. Published methods describe limits of detection in the low nanogram per milliliter range for related compounds. Exact detection windows are not fixed for all situations and remain an area of ongoing study.
| Property | Value | Notes |
|---|---|---|
| Common name | Cardarine | Common internet and media name. |
| Research code | GW501516 | Also written GW-1516. |
| Drug class | PPARδ agonist | Not a selective androgen receptor modulator. |
| Development status | Discontinued | Clinical development halted after rodent cancer findings. |
| Regulatory status | Prohibited in sport | Listed by WADA; not approved as medicine. |
PPARδ is a nuclear receptor that influences transcription of genes involved in fatty acid oxidation, lipid transport, and energy homeostasis. GW501516 binds and activates this receptor with high selectivity relative to PPARα and PPARγ in laboratory assays. Activation alters expression of target genes in skeletal muscle, liver, and adipose tissue in animal models. The exact clinical consequences of these changes in humans remain incompletely characterized, and observed effects in animals do not establish therapeutic benefit or safety.
Published studies have examined GW501516 in animal models of obesity, insulin resistance, and exercise endurance. Early human trials reportedly ended, and development was discontinued after preclinical findings raised concerns about cancer in some rodent studies. Regulatory agencies have not approved cardarine for any medical use. Its availability through non-pharmaceutical channels raises questions about identity, purity, and legal status that are separate from its laboratory pharmacology. Those questions are often addressed through analytical testing rather than assumptions about product labels.
Cardarine is a common name for GW501516, also GW-1516, a synthetic compound developed as a peroxisome proliferator-activated receptor delta (PPARδ) agonist. It belongs to a class of agents that modulate gene transcription related to lipid and energy metabolism. The compound was studied in preclinical and early clinical research for metabolic and cardiovascular conditions, but it did not progress to approved therapeutic use. Its name appears in fitness and sports contexts despite not being approved as a drug.
Cardarine has no approved therapeutic indication and is not marketed as a medicine. The World Anti-Doping Agency lists GW501516 as a prohibited substance at all times, covering both in-competition and out-of-competition periods. National laws vary: some countries treat it as an unapproved drug subject to import controls, while others have specific restrictions on sale for human consumption. It is often sold as a research chemical, a label that does not imply safety or legality. Enforcement actions have targeted online vendors and shipments.
Anti-doping laboratories identify GW501516 and related metabolites using liquid chromatography coupled with tandem mass spectrometry. Urine is the most common matrix, though blood and dried blood spots may also be analyzed. The method targets the parent compound and phase I and phase II metabolites, which extend the detection window. Because the substance is prohibited at all times, athletes can be tested outside competition. Detection limits and windows depend on the assay, sample type, and individual metabolism.
The pharmacological interest in cardarine centers on PPARδ activation and its downstream effects on lipid handling and mitochondrial function. In animal studies, PPARδ agonists have been associated with changes in exercise endurance and fatty acid utilization, though results vary by model and protocol. Human data remain sparse, and the absence of large controlled trials limits conclusions about efficacy. Researchers often describe the compound as a tool for probing PPARδ biology rather than a proven therapeutic agent.
Safety discussions about cardarine frequently cite rodent carcinogenicity findings reported in the 2000s. In those studies, treated animals developed tumors at multiple sites, leading sponsors to discontinue clinical development. The relevance of these findings to humans has not been resolved, but they are a major reason the compound is not approved. Current literature emphasizes uncertainty about long-term effects and the risks of unregulated use. Regulators and health agencies have not established a safe human exposure level.
Cardarine is a synthetic compound also known as GW501516, GW-501516, and sometimes endurobol. It was developed as a selective agonist of peroxisome proliferator-activated receptor delta, a nuclear receptor involved in fatty acid oxidation and energy metabolism. The compound was studied in preclinical models for metabolic and cardiovascular conditions, but it did not become a marketed human medicine. In regulatory and anti-doping contexts, it is treated as a prohibited substance rather than a licensed medicine.
The introduction of the F gene of SeV in the form of a plasmid into the tumor tissue in mice by electroporation showed that the expression of the F gene increases the T cell infiltration of the tumor with CD4+ and CD8+ cells and inhibits tumor growth. It was also shown in other similar experiments that cancer cells themselves, transfected with plasmids that encode viral membrane glycoproteins with fusion function, cause the collective death of neighboring cells forming syncytium with them. Recruitment of bystander cells into the syncytium leads to significant regression of the tumor.
Another source of error is the difficulty in standardizing the amount of bacteria in the sample (the inoculum), which has a profound effect on the test results. Genetic testing can be used for rapid detection of certain antimicrobial resistance markers. Methods such as PCR and microarrays, which can be performed directly on positive blood culture samples, detect DNA sequences associated with genes that confer resistance, such as the mecA gene found in methicillin-resistant Staphylococcus aureus or the vanA and vanB genes of vancomycin-resistant enterococci. MALDI-TOF has been explored as a rapid antimicrobial sensitivity testing method; principles involve measuring microbial growth in the presence of antibiotics, identifying the breakdown of antibiotics by microbial enzymes, and detecting protein spectra associated with bacterial strains that exhibit antibiotic resistance. Some of these methods can be performed on pellets from positive blood culture bottles. However, the lack of established methodologies for AST by MALDI-TOF limits its use in clinical practice, and direct AST by MALDI-TOF, unlike genetic testing methods, had not been approved by the Food and Drug Administration as of 2018.
=== Spectral skewing === Spectral skewing is the change in relative intensity of mass spectral peaks due to the changes in concentration of the analyte in the ion source as the mass spectrum is scanned. This situation occurs routinely as chromatographic components elute into a continuous ion source. Spectral skewing is not observed in ion trap (quadrupole (this has been seen also in QMS) or magnetic) or time-of-flight (TOF) mass analyzers because potentially all ions formed in operational cycle (a snapshot in time) of the instrument are available for detection.
The total period of time beginning with the date of manufacture, date of cure (for elastomeric and rubber products only), date of assembly, or date of pack (subsistence only), and terminated by the date by which an item must be used (expiration date) or subjected to inspection, test, restoration, or disposal action; or after inspection/laboratory test/restorative action that an item may remain in the combined wholesale (including manufacture's) and retail storage systems and still be suitable for issue or use by the end user. Shelf-life is not to be confused with service-life (defined as, A general term used to quantify the average or standard life expectancy of an item or equipment while in use. When a shelf-life item is unpacked and introduced to mission requirements, installed into intended application, or merely left in storage, placed in pre-expended bins, or held as bench stock, shelf-life management stops and service life begins.)
Over a two-year period, close to $800 million worth of fentanyl was illegally sold online to the US by Chinese distributors. The drug is usually manufactured in China, then shipped to Mexico, where it is processed and packaged, which is then smuggled into the US by drug cartels. A large amount is also purchased online and shipped through the US Postal Service. It can also be purchased directly from China, which has become a major manufacturer of various synthetic drugs illegal in the US. AP reporters found multiple sellers in China willing to ship carfentanyl, an elephant tranquilizer that is so potent it has been considered a chemical weapon. The sellers also offered advice on how to evade screening by US authorities. According to Assistant US Attorney Matt Cronin in 2019:
Sources: en.wikipedia.org
== Treatments == Consult a hematologist and have regular blood check ups. Have an early diagnostic test for any blood disorders or blood diseases including hemophilia, hemorrhage, and sickle-cell anemia. Prothrombin time and partial thromboplastin time blood tests are useful to investigate the reason behind the excessive bleeding. The PT evaluates coagulation factors I, II, V, VII and X, while the PTT evaluates coagulation factors I, II, V, VIII, IX, X, XI and XII. The analysis of both tests thus helps to diagnose certain disorders. Blood transfusion involves the transfer of plasma containing all the necessary coagulating factors (fibrinogen, prothrombin, thromboplastin) to help restore them and to improve the immune defense of the patient after excessive blood loss. Blood transfusion also caused the transfer of platelets that can work along with coagulating factors for blood clotting to commence. Different drugs can be prescribed depending on the type of disease. Vitamins (K, P and C) are essential in case of obstruction to walls of blood vessels. Also, vitamin K is required for the production of blood clotting factors, hence the injection of vitamin K (phytomenadione) is recommended to boost blood clotting.
== Structural studies == As of late 2007, 6 structures have been solved for this class of enzymes, with PDB accession codes PDB: 1DO8, PDB: 1EFK, PDB: 1EFL, PDB: 1GZ3, PDB: 1LLQ, PDB: 1O0S, PDB: 1PJ2, PDB: 1PJ3, PDB: 1PJ4, PDB: 1PJL, PDB: 1QR6, PDB: 1WW8, and PDB: 2DVM.
== The Strep-tag principle == Just like other short-affinity tags (His-tag, FLAG-tag), the Strep-tag can be easily fused to recombinant proteins during subcloning of its cDNA or gene. For its expression, various vectors for various host organisms (E. coli, yeast, insect, and mammalian cells) are available. A particular benefit of the Strep-tag is its rather small size and the fact that it is biochemically almost inert. Therefore, protein folding or secretion is not influenced and usually it does not interfere with protein function. Strep-tag is especially suited for analysis of functional proteins, because the purification procedure can be kept under physiological conditions. This not only allows the isolation of sensitive proteins in a native state, but it is also possible to purify intact protein complexes, even if just one subunit carries the tag. In the first step of the Strep-tag purification cycle, the cell lysate containing Strep-tag fusion protein is applied to a column with immobilized Strep-Tactin (step 1). After the tagged protein has specifically bound to Strep-Tactin, a short washing step with a physiological buffer (e.g. phosphate buffered saline, PBS) removes all other host proteins (step 2). This is due to Strep-Tactin's low tendency to bind proteins non specifically. Then, the purified Strep-tag fusion protein is gently eluted with a low concentration of desthiobiotin, which specifically competes for the biotin binding pocket (step 3). To regenerate the column, desthiobiotin is removed by application of a HABA containing solution (a yellow azo dye).
== Wimley–White whole residue hydrophobicity scales == The Wimley–White whole residue hydrophobicity scales are significant for two reasons. First, they include the contributions of the peptide bonds as well as the sidechains, providing absolute values. Second, they are based on direct, experimentally determined values for transfer free energies of polypeptides.
Sources: en.wikipedia.org
No. Cardarine is a PPARδ agonist, while selective androgen receptor modulators act on androgen receptors. The two classes differ in receptor target and downstream effects.
Preclinical rodent studies reported cancers, including liver and bladder tumors, at tested doses. The human relevance of those findings is uncertain, but development was discontinued. No approved human product resulted.
No. It remains an investigational compound without approved therapeutic labeling. Sports regulators prohibit its use, and health agencies have warned against consuming it.
Legal status varies by country, but cardarine is not approved as a medicine in major jurisdictions. It is often sold as a research chemical, a category that may not be lawful for human use. Buyers should check local laws and product labels carefully.