A practical reference on GW501516: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
This page was last updated on 2026-07-02 and is reviewed periodically as new material appears.
Cardarine is a common name for GW501516, a synthetic compound developed in the 1990s through research collaborations involving GlaxoSmithKline. It belongs to a class of molecules known as peroxisome proliferator-activated receptor delta agonists. Early studies explored its effects on lipid metabolism and energy expenditure in animal models. The compound was never approved as a human medicine, and clinical development was discontinued. In the years since, it has appeared in fitness and bodybuilding communities as a performance-enhancing substance. Regulatory agencies classify it as an unapproved drug.
PPARδ is a nuclear receptor that regulates gene expression related to fatty acid oxidation, glucose homeostasis, and mitochondrial function. GW501516 binds to this receptor with high affinity and activates downstream signaling in skeletal muscle and other tissues. Animal studies reported increased endurance and altered fuel preference, but human data remain limited and inconsistent. The precise relationship between receptor activation and observed physiological changes is still an area of active investigation. Researchers have also examined whether the compound affects inflammation or cell proliferation. No approved therapeutic indication exists for cardarine.
In laboratory settings, cardarine is studied as a tool compound for probing PPARδ biology. Published experiments often use cell cultures, rodent models, or isolated tissues. Some investigations focus on metabolic effects, while others assess potential risks such as carcinogenicity observed in long-term animal studies. Because human trials are sparse, most knowledge comes from preclinical work and adverse event reports. Scientific literature frequently notes the gap between animal findings and human outcomes. The compound is not a dietary supplement and is not intended for human consumption.
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.
Cardarine is frequently described as a fat-burning or endurance-enhancing supplement, but these claims exceed the available evidence. The compound is not a hormone, steroid, or selective androgen receptor modulator. Research articles discuss it as a tool compound for studying PPARδ biology, while anti-doping literature focuses on its abuse and detection. Quality of unapproved products is uncertain, and independent analyses have found impurities or incorrect labeling. Open questions include whether human cancer risk resembles that seen in rodents and how often non-athletes use the substance.
| Property | Value | Notes |
|---|---|---|
| CAS Registry Number | 317318-70-0 | Unique identifier for the compound. |
| Chemical class | PPARδ agonist | Synthetic ligand for peroxisome proliferator-activated receptor delta. |
| Appearance | White to off-white solid | Typical form of research-grade material. |
| Solubility | Soluble in DMSO and ethanol | Poorly soluble in water. |
| Typical storage | -20°C | Recommended for long-term storage of stock solutions. |
Handling and quality assessment of cardarine reference material follow general laboratory practices for poorly characterized compounds. It typically appears as a white to off-white powder and is sparingly soluble in water but soluble in organic solvents such as dimethyl sulfoxide and ethanol. Storage recommendations usually specify a cool, dry, dark place, with long-term storage at low temperature and desiccation. Purity may be checked by high-performance liquid chromatography with ultraviolet detection, while identity is confirmed by mass spectrometry and nuclear magnetic resonance. No pharmacopeial monograph exists, so reported purity and stability depend on the supplier’s methods.
GW501516 acts as a selective agonist at PPARδ, a nuclear receptor that regulates transcription of genes involved in lipid handling and energy metabolism. Activation of PPARδ in preclinical models increases fatty acid oxidation, mitochondrial biogenesis, and exercise endurance in rodents. These effects have made the compound a subject of metabolic research and also a target for sport anti-doping rules. In humans, however, controlled studies are limited, and whether similar endurance or metabolic changes occur at tolerated exposures remains an open question. The receptor’s broad tissue distribution also means downstream effects may vary by organ and condition.
Detection of GW501516 in biological samples generally relies on liquid chromatography coupled with tandem mass spectrometry. Urine is a common matrix in anti-doping analysis, while blood or plasma may be used in research settings. Sample preparation can involve enzymatic hydrolysis, protein precipitation, or solid-phase extraction before instrumental analysis. Because the compound undergoes metabolism, assays may target the parent molecule, one or more metabolites, or both. Detection windows are not fixed; they depend on factors such as dose, route, individual metabolism, and assay sensitivity. Reference standards are required for accurate identification and quantification.
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.
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.
GW501516 acts as a ligand for PPAR delta, a nuclear receptor that regulates transcription of genes involved in fatty acid oxidation and energy use. Activation of this receptor in skeletal muscle shifts metabolism toward fat burning in animal models. The compound does not burn fat directly; it changes gene expression over hours to days. Researchers study it to understand metabolic flexibility and exercise adaptation. Effects observed in rodents are not automatically expected in humans.
Preclinical research reported that GW501516 increased running endurance in mice and improved lipid profiles in some animal species. Early human trials explored effects on high-density lipoprotein cholesterol, triglycerides, and glucose handling, but the program was discontinued. Published human data are sparse and do not establish efficacy for any condition. Studies also examined PPAR delta in cancer biology, with conflicting findings across models. The relationship between receptor activation, tissue context, and disease risk remains an active area of investigation.
==== Biomolecular mechanisms ==== Chronic use of amphetamine at excessive doses causes alterations in gene expression in the mesocorticolimbic projection, which arise through transcriptional and epigenetic mechanisms. The most important transcription factors that produce these alterations are Delta FBJ murine osteosarcoma viral oncogene homolog B (ΔFosB), cAMP response element binding protein (CREB), and nuclear factor-kappa B (NF-κB). ΔFosB is the most significant biomolecular mechanism in addiction because ΔFosB overexpression (i.e., an abnormally high level of gene expression which produces a pronounced gene-related phenotype) in the D1-type medium spiny neurons in the nucleus accumbens is necessary and sufficient for many of the neural adaptations and regulates multiple behavioral effects (e.g., reward sensitization and escalating drug self-administration) involved in addiction. Once ΔFosB is sufficiently overexpressed, it induces an addictive state that becomes increasingly more severe with further increases in ΔFosB expression. It has been implicated in addictions to alcohol, cannabinoids, cocaine, methylphenidate, nicotine, opioids, phencyclidine, propofol, and substituted amphetamines, among others. ΔJunD, a transcription factor, and G9a, a histone methyltransferase enzyme, both oppose the function of ΔFosB and inhibit increases in its expression. Sufficiently overexpressing ΔJunD in the nucleus accumbens with viral vectors can completely block many of the neural and behavioral alterations seen in chronic drug abuse (i.e., the alterations mediated by ΔFosB).
Nanospray desorption electrospray ionization (nano-DESI) is an ambient pressure ionization technique used in mass spectrometry (MS) for chemical analysis of organic molecules. In this technique, analytes are desorbed into a liquid bridge formed between two capillaries and the sampling surface. Unlike desorption electrospray ionization (DESI), from which nano-DESI is derived, nano-DESI makes use of a secondary capillary, which improves the sampling efficiency.
=== The Sean Duffy series === The Cold Cold Ground (Serpent's Tail) 2012 ISBN 978-1616147167 I Hear the Sirens in the Street (Serpent's Tail) 2013 ISBN 978-1616147877 In the Morning I'll Be Gone (Serpent's Tail) 2014 ISBN 978-1616148775 Gun Street Girl (Serpent's Tail) 2015 ISBN 978-1633880009 Rain Dogs (Serpent's Tail) 2016 ISBN 978-1633881303 Police at the Station and They Don't Look Friendly (Serpent's Tail) 2017 ISBN 1781256926 The Detective Up Late (Blackstone) 2023 Hang On St Christopher (Blackstone) 2025 The Ghosts Of Saturday Night TBD Two more Sean Duffy novels to be published by Blackstone Publishing On a blog post dated July 15, 2021, on his official site, McKinty explains that the 7th Sean Duffy novel (The Detective Up Late) may be out in late 2022. He states that The Detective Up Late is in fact finished and Book 8 (Hang On St Christopher) is pretty much done.
=== Diversity, equity, and inclusion === Gallrein is opposed to the idea of diversity, equity, and inclusion and believes that these principles should be removed from schools, the military, and the government.
Sources: en.wikipedia.org
== N == NEMS-MS – Nanoelectromechanical systems mass spectrometry NETD – Negative electron-transfer dissociation NICI – Negative ion chemical ionization NRMS – Neutralization reionization mass spectrometry
=== Pharmacodynamics === Dihydroergotamine's antimigraine activity is due to its action as an agonist at the serotonin 5-HT1B, 5-HT1D, and 5-HT1F receptors. It also interacts with other serotonin, adrenergic, and dopamine receptors. Dihydroergotamine is an agonist of the serotonin 5-HT2B receptor and has been associated with cardiac valvulopathy. In spite of acting as an agonist of the serotonin 5-HT2A receptor, dihydroergotamine has been described as non-hallucinogenic. This is also the case with certain other ergoline derivatives, such as bromocriptine and pergolide.
Osedax is a genus of siboglinid polychaetes, commonly called snot worms, bone-eating worms, or zombie worms. Osedax is Latin for 'bone devourer', derived from the worms' unique ecological niche of bone-boring. Osedax settle on a bone, then secrete an acid through specialized root tissues to dissolve the bone's external layers in order to access the lipids within. Osedax act as ecosystem engineers, enhancing the biodiversity of bones they inhabit by increasing their structural complexity, allowing microfauna to inhabit otherwise inaccessible regions of the internal bone. Scientists from the Monterey Bay Aquarium Research Institute using the submarine ROV Tiburon first discovered the genus in Monterey Bay, California, in February 2002. The worms were found living on the bones of a decaying gray whale in the Monterey Canyon, at a depth of 2,893 m (9,491 ft).
=== Diagnosis === According to one review: "At present, no 'gold standard' test exists for the diagnosis of vitamin B12 deficiency and as a consequence the diagnosis requires consideration of both the clinical state of the patient and the results of investigations." The vitamin deficiency is typically suspected when a routine complete blood count shows anemia with an elevated mean corpuscular volume (MCV). In addition, on the peripheral blood smear, macrocytes and hypersegmented polymorphonuclear leukocytes may be seen. Diagnosis is supported based on vitamin B12 blood levels below 150–180 pmol/L (200–250 pg/mL) in adults. However, serum values can be maintained while tissue B12 stores are becoming depleted. Therefore, serum B12 values above the cut-off point of deficiency do not necessarily confirm adequate B12 status. For this reason, elevated serum homocysteine over 15 micromol/L and methylmalonic acid (MMA) over 0.271 micromol/L are considered better indicators of B12 deficiency, rather than relying only on the concentration of B12 in blood. However, elevated MMA is not conclusive, as it is seen in people with B12 deficiency, but also in elderly people who have renal insufficiency, and elevated homocysteine is not conclusive, as it is also seen in people with folate deficiency. In addition, elevated methylmalonic acid levels may also be related to metabolic disorders such as methylmalonic acidemia. If nervous system damage is present and blood testing is inconclusive, a lumbar puncture may be carried out to measure cerebrospinal fluid B12 levels.
Multiple testing was done to be able to narrow down whether his form of Syncope is caused by mental factors or cardiac abnormalities, the results are still pending. Dr. Lisa Sanders took Matt’s story to the column and awaited for responses from the audience with ideas. Out of the hundreds of responses, only two were the most cohesive towards Matt’s symptoms. The first possibility was Vasovagal Syncope, where the nervous system will send an incorrect message too slow down the heart and can cause it to stop, the tilt table test performed on Matt could provide a definitive answer to this theory. The second possibility is Temporal lobe epilepsy which is a kind of seizure that is correlated to a sense of “strange” thoughts, feelings, or sense of Deja Vu. Matt was subjected to an EEG which did not show any preliminary seizure disorders, however the specialist who reviewed his results noted that the EEG might not express any deep temporal lobe seizures. The tilt table test performed on Matt came back negative for Vasovagal Syncope, however Matt was fitted with a heart tracker to be able to detect any abnormal signals within the heart during an episode. Matt finally had an episode with his heart loop tracker, the tracker was able to detect a 6 second heart stop during his episode. On the same day Matt had this episode he had another one once his stress level started to rise, this was the first time in the entire duration of his illness that he's had two episodes in one day. Dr.
Sources: en.wikipedia.org
Cardarine is a common name for GW501516, a synthetic PPARδ agonist developed for research. It has not been approved as a medication in any country. It is classified as an unapproved drug and a prohibited substance in sport.
No. Cardarine is not an anabolic steroid; it belongs to a different chemical class that targets PPARδ. Steroids act primarily through androgen receptors, while cardarine acts through a nuclear receptor involved in metabolism.
Some rodent studies reported increased endurance and changes in fat metabolism after cardarine exposure. Long-term studies in animals also raised concerns about cancer in certain tissues. Human trial data are limited, so these findings cannot be directly translated to people.
Legal status varies by country. It is not approved as a medicine, and it is prohibited in sport. Some jurisdictions restrict import, sale, or possession.