Nuclear receptor 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.
Updated 2026-08-01. Numbers and descriptions here follow the published literature rather than marketing material.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Regulatory status | Prohibited in sport | Listed by WADA as a metabolic modulator. |
| Approved medical use | None in major jurisdictions | Not a registered drug. |
| Common test matrix | Urine | Most anti-doping samples use urine. |
| Typical detection method | LC-MS/MS | Detects parent compound and metabolites. |
| Reference standard storage | -20 °C, desiccated | Typical for analytical standards. |
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.
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.
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.
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.
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 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.
Soy products such as tofu and tempeh, (which contain the inhibitor "genistein") Agaricus subrufescens mushrooms (contain the inhibitors sodium pyroglutamate and ergosterol) Black raspberry (Rubus occidentalis) extract Lingzhi mushrooms (via inhibition of VEGF and TGF-beta) Trametes versicolor mushrooms (Polysaccharide-K) Maitake mushrooms (via inhibition of VEGF) Phellinus linteus mushrooms (via active substance Interfungins A inhibition of glycation) Green tea (catechins) Liquorice (glycyrrhizic acid) Red wine (resveratrol) Antiangiogenic phytochemicals and medicinal herbs Royal jelly (queen bee acid)
=== Failed proposed changes === 2015: Proposals to amalgamate local councils in Wellington and Northland were accepted by the Local Government Commission for consideration, although following consultation they ultimately were not formed into a final proposal. The status quo remains. 2015: Amalgamation of four local councils and the regional council in Hawke's Bay was proposed by the Local Government Commission. A district wide referendum was held in Sep-2015, and the proposal was defeated by 66% of voters. 2015: The Local Government Commission received a proposal to review local government arrangements on the West Coast. In August 2016 the Commission decided to progress the application. The Commission then invited alternative applications to the original application. The Commission's call for alternative reorganisation applications or other proposals for change to West Coast local government arrangements closed on 15 March 2017. The Commission received 23 responses, 19 of which made specific proposals for change. In December 2017 the Local Government Commission determined its preferred option for local government reorganisation on the West Coast to be the transfer of district plan preparation from the Buller, Grey and Westland district councils to the West Coast Regional Council. 2017: The Local Government Commission received a proposal to amalgamate the Masterton, Carterton and South Wairarapa District Councils into a combined Wairarapa District Council. The proposal was defeated by referendum with 59% of voters rejecting the proposed merger.
=== Olmutinib safety concerns === On September 30, 2016, Korean regulatory authorities issued a safety alert about olmutinib in which it described two cases of toxic epidermal necrolysis, one of which was fatal, and a case of Stevens–Johnson syndrome; Boeheringer announced the termination its deal with Hanmi the same day, citing that the decision came after a review of "all available clinical data" on the drug, and also referring to competing drugs. In April 2018 Hanmi was found to have violated two laws in Korea by not disclosing adverse effects of olmutinib sooner. In that month Zai said it was dropping olmutinib and a few days later Hanmi said it was terminating development of the drug.
=== Influenza === A study of an outbreak of an (H1N1) influenza in an Israeli military unit of 336 healthy young men to determine the relation of cigarette smoking to the incidence of clinically apparent influenza, revealed that, of 168 smokers, 69% had influenza, as compared with 47% of non-smokers. Influenza was also more severe in the smokers; 51% of them lost work days or required bed rest, or both, as compared with 30% of the non-smokers. According to a study of 1,900 male cadets after the 1968 Hong Kong A2 influenza epidemic at a South Carolina military academy, compared with people who did not smoke, people who smoked heavily (more than 20 cigarettes per day) had 21% more illnesses and 20% more bed rest, people who smoked lightly (20 cigarettes or fewer per day) had 10% more illnesses and 7% more bed rest. The effect of cigarette smoking on epidemic influenza was studied prospectively among 1,811 male college students. Clinical influenza incidence among those who smoked 21 or more cigarettes daily was 21% higher than that of people who did not smoke. Influenza incidence among people who smoked 1 to 20 cigarettes daily was intermediate between those who did not smoke and people who smoked heavily. Surveillance of a 1979 influenza outbreak at a military base for women in Israel revealed that influenza symptoms developed in 60% of the current smokers vs. 42% of the non-smokers. Smoking seems to cause a higher relative influenza risk in older populations than in younger populations.
=== 15 April === Poland and Hungary banned imports of grain and some other food from Ukraine "to protect the local agricultural sector", due to Ukrainian supplies lowering the price of food. The bans were criticized by the Ukrainian Ministry of Agrarian Policy as contradicting bilateral agreements on exports, while the European Commission said that "unilateral actions are not acceptable". Jarosław Kaczyński, the leader of the Polish Law and Justice party, said that Poland will continue supporting Ukraine and that it was ready to start talks to settle the issue.
Sources: en.wikipedia.org
Some of a patient's single nucleotide polymorphisms—slight differences in their DNA—can help predict how quickly they will metabolise particular drugs; this is called pharmacogenomics. For example, the enzyme CYP2C19 metabolises several drugs, such as the anti-clotting agent Clopidogrel, into their active forms. Some patients possess polymorphisms in specific places on the 2C19 gene that make poor metabolisers of those drugs; physicians can test for these polymorphisms and find out whether the drugs will be fully effective for that patient. Advances in molecular biology have helped show that some syndromes that were previously classed as a single disease are actually multiple subtypes with entirely different causes and treatments. Molecular diagnostics can help diagnose the subtype—for example of infections and cancers—or the genetic analysis of a disease with an inherited component, such as Silver-Russell syndrome.
=== μ-opioid receptors === In clinical trials, the MOR is the main target of opioid ligand binding. While binding of the opioid to the MOR typically causes analgesia, there can be instances where hyperalgesia occurs. It has been speculated that the opposite analgesic and hyperanalgesic effects are due to different isoforms of the receptor. The MOR is a G protein-coupled receptor with seven transmembrane domains. Variants of the receptor have been discovered and are due to alternative splicing mechanisms. A particular receptor variant, 6TM MOR, has been heavily studied because of its role in nociception. The 6TM MOR is missing residues in the N-terminal region which has implications for the extracellular tail and first transmembrane domain. This causes an excitatory effect compared to the inhibition in the normal seven transmembrane domain receptor because of differences in G-protein activation. Studies on mice have shown silencing of the 6TM MOR variant decreased morphine-induced hyperalgesia which suggested G-protein coupling in the 6TM isoform could be a factor in the development of OIH.
=== Other formulations === The original oral formulation of selegiline was developed for the treatment of depression. However, it ended up being developed and approved for the treatment of Parkinson's disease instead. In any case, oral selegiline has been widely used off-label to treat depression. The transdermal patch form of selegiline was developed and approved specifically for the treatment of depression. It was also under development for the treatment of Alzheimer's disease, attention deficit hyperactivity disorder (ADHD), cognition disorders, and Parkinson's disease, but development for these indications was discontinued. The ODT form of selegiline was developed and licensed exclusively for the treatment of Parkinson's disease.
The yellow pulp, which contains the seeds, is naturally sweet and is processed into a valuable carbohydrate food. The seeds are processed into a seasoning, known as sikomu and dodowa/ dawadawa among the Yoruba and Hausa people respectively, and sunbala in the Inner Niger Delta. The pulp is also used to make beverages. The seeds of the locust bean are the most valuable part of the plant. They are high in lipids (29%), protein (35%), carbohydrates (16%), and are a good source of fat and calcium for rural dwellers. The seed is first cooked to remove the seed coat and then fermented to produce the desired result. Seeds can then be pounded into powder, then formed into cakes. In a study conducted on the fermentation of dawadawa, it was found that Gmelina arborea and banana leaves accelerated fermentation of seeds, while increasing fat, protein and moisture content, but also decreasing carbohydrate content.
Sources: en.wikipedia.org
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.
Anti-doping laboratories use LC-MS/MS to detect GW501516 and its metabolites, usually in urine. The method can identify the parent compound at low concentrations. Detection windows vary with dose and individual factors.
No, cardarine has no approved medical uses in major jurisdictions. Early research explored metabolic conditions, but those programs were discontinued. It is not a registered treatment for any disease.
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.