PPARδ 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 2026-04-25. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
| 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. |
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 is a common name for GW501516, a synthetic compound first described in the 1990s as a selective agonist of the peroxisome proliferator-activated receptor delta. It was studied in preclinical models for metabolic and cardiovascular conditions, but it has not been approved as a medicine in the United States, Europe, or other major jurisdictions. Retail products labeled as cardarine are generally research chemicals or supplements, not pharmaceutical formulations. Because human safety and efficacy data remain limited, regulatory agencies treat it as an unapproved substance rather than a therapeutic product.
Sporting authorities added GW501516 to prohibited lists after it appeared in athlete samples and online markets. The World Anti-Doping Agency classifies it as a hormone and metabolic modulator, and its use can lead to an anti-doping rule violation. Some early laboratory work suggested effects on fatty acid oxidation and endurance-related metabolism in animals, but those findings do not establish safe or effective use in people. Reports of adverse events in humans are scarce and often anecdotal, which complicates risk assessment.
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.
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.
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.
Anti-doping laboratories identify GW501516 and its metabolites using liquid chromatography-tandem mass spectrometry. Urine is the usual matrix, and detection can occur after the parent compound has cleared from blood. The exact detection window depends on dose, formulation, individual metabolism, and assay sensitivity. Because the compound is prohibited at all times, athletes are subject to testing in and out of competition. Analytical methods continue to improve as new metabolites and designer analogs are characterized.
=== Swine Flu Outbreak === In 2009, Hetero established Hetero Biopharma, a dedicated R&D unit, and set up a biological manufacturing unit in Hyderabad and quickly became a manufacturer of affordable biosimilars. In the same year, Hetero garnered widespread attention for its public health emergency response capabilities during the Swine Flu outbreak. As various health organizations and government agencies were piling up stocks of Oseltamivir as precautionary measures, Hetero supplied generic Oseltamivir under its brand name Fluvir. Hetero delivered 10 million doses of Oseltamivir to the Indian government in 2009, and shipped about 80 million doses to over 60 countries.Hetero received its second order from Indian government to supply another 10 million doses of Oseltamivir later in 2009. 2014-2019 In 2014, Hetero launched the blockbuster drug Sofosbuvir, a direct-acting antiviral used for the treatment of Hepatitis C, with approval from Gilead Sciences. The drug was marketed and sold in 90 countries, including India, Asia Pacific, Sub-Saharan Africa and other least developed countries, making it accessible at a substantially lower cost to patients. In 2015, Hetero took a step further in Hep C care by becoming the first company in India to launch the fixed-dose combination of Ledipasvir+ Sofosbuvir, used in the treatment of chronic hepatitis genotype 1 in both treatment –naïve and treatment experienced patients.
==== Metabolism ==== The metabolic pathways involved in the metabolism are not well-characterized. In any case, the cytochrome P450 enzymes CYP3A4, CYP2D6, and CYP1A2 may all be involved to varying extents. Trazodone is known to be extensively metabolized by the liver via hydroxylation, N-oxidation, and N-dealkylation. Several metabolites of trazodone have been identified, including a dihydrodiol metabolite (via hydroxylation), a metabolite hydroxylated at the para position of the meta-chlorophenyl ring (via CYP2D6), oxotriazolepyridinepropionic acid (TPA) and mCPP (both via N-dealkylation of the piperazinyl nitrogen mediated by CYP3A4), and a metabolite formed by N-oxidation of the piperazinyl nitrogen. CYP1A2, CYP2D6, and CYP3A4 genotypes all do not seem to predict concentrations of trazodone or mCPP. In any case, there are large interindividual variations in the metabolism of trazodone. In addition, poor metabolizers of dextromethorphan, a CYP2D6 substrate, eliminate mCPP more slowly and have higher concentrations of mCPP than extensive metabolizers. mCPP is formed from trazodone by CYP3A4 and is metabolized via hydroxylation by CYP2D6 (to a para-hydroxylated metabolite). It may contribute to the pharmacological actions of trazodone. mCPP levels are only 10% of those of trazodone during therapy with trazodone, but is nonetheless present at concentrations known to produce psychic and physical effects in humans when mCPP has been administered alone. In any case, the actions of trazodone, such as its serotonin antagonism, might partially overwhelm those of mCPP.
=== Single-molecule force spectroscopy === Single molecule techniques such as optical tweezers and AFM have been used to understand protein folding mechanisms of isolated proteins as well as proteins with chaperones. Optical tweezers have been used to stretch single protein molecules from their C- and N-termini and unfold them to allow study of the subsequent refolding. The technique allows the measurement of folding rates at single-molecule level; for example, optical tweezers have been recently applied to study folding and unfolding of proteins involved in blood coagulation. von Willebrand factor (vWF) is a protein with an essential role in blood clot formation process. It was discovered – using single molecule optical tweezers measurement – that calcium-bound vWF acts as a shear force sensor in the blood. Shear force leads to unfolding of the A2 domain of vWF, whose refolding rate is dramatically enhanced in the presence of calcium. It has also been shown that the simple src SH3 domain accesses multiple unfolding pathways under force.
== Age-related prevalence of the CKM syndrome == A study of 231,590,853 individuals living in the USA found older aged patients trended to have higher stages of the CKM syndrome. In the 20-44 years old age group 17.3% were stage 0, 37.6% were stage 1, 43.2% % were stage 2, 0.2% were stage 3, and 1.7% were stage 4. In the 45 to 64 years old group, 5.4% were stage 0, 21.0% were stage 1, 63.8% were stage 2, 1.2 % were stage 3, and 8.6% were stage 4. In the 65 years and older age group, 1.8% were stage 0, 8.4% were stag 1, 39.0% were stage 2, 24.6% were stage 3, and 26.2% were stage 4. The 20 to 44, 45 to 64, and 65 or greater years old groups consisted respectively of 104,113,793, 82,640,261, and 44,836,799 individuals.
== Pathways == The protein C pathways are the specific chemical reactions that control the level of expression of APC and its activity in the body. Protein C is pleiotropic, with two main classes of functions: anticoagulation and cytoprotection (its direct effect on cells). Which function protein C performs depends on whether or not APC remains bound to EPCR after it is activated; the anticoagulative effects of APC occur when it does not. In this case, protein C functions as an anticoagulant by irreversibly proteolytically inactivating Factor Va and Factor VIIIa, turning them into Factor Vi and Factor VIIIi respectively. When still bound to EPCR, activated protein C performs its cytoprotective effects, acting on the effector substrate PAR-1, protease-activated receptor-1. To a degree, APC's anticoagulant properties are independent of its cytoprotective ones, in that expression of one pathway is not affected by the existence of the other. The activity of protein C may be down-regulated by reducing the amount either of available thrombomodulin or of EPCR. This may be done by inflammatory cytokines, such as interleukin-1β (IL-1β ) and tumor necrosis factor-α (TNF-α). Activated leukocytes release these inflammatory mediators during inflammation, inhibiting the creation of both thrombomodulin and EPCR, and inducing their shedding from the endothelial surface. Both of these actions down-regulate protein C activation. Thrombin itself may also have an effect on the levels of EPCR.
Sources: en.wikipedia.org
Research mainly focuses on polymers that show thermoresponsivity in aqueous solution. Promising areas of application are tissue engineering, liquid chromatography, drug delivery and bioseparation. Only a few commercial applications exist, for example, cell culture plates coated with an LCST-polymer.
==== Signalling ==== In innate immunity TLRs play an important role. These TLRs (mainly TLR7 and TLR9) can be proteolytically activated by AEP. The reduction of proinflammatory cytokines by stimulating TLR9 was found in myeloid cells and plasmacytoid dendritic cells which lacked AEP. Enzyme is also important in processing of influenza virus and immune response using TLR7. AEP plays a critical role in TLR processing. and AEP can initiate removal of invariant chain in MHC-II complex, which can critically influence peptide generation and activity of MHCII.
However, this difference is usually neglected most of the time (that is whenever we are not dealing with processes such as sound absorption and attenuation of shock waves, where second viscosity coefficient becomes important) by explicitly assuming
Afghanistan: The Foreign Ministry stipulated that the Assad regime was the "cause of war and instability" and congratulated Tahrir al-Sham. Canada: Prime Minister Justin Trudeau said that the fall of the Assad dictatorship "ends decades of brutal oppression" and said that Canada is monitoring the transition closely. China: The Foreign Ministry stated that it "is closely following the development of the situation in Syria and hopes that Syria returns to stability as soon as possible" and urged all parties to ensure the safety of Chinese citizens in Syria. European Union: EU foreign policy chief Kaja Kallas called the end of Assad's rule a "positive and long-awaited development" and stated she was in close contact with regional ministers. She emphasized that rebuilding Syria would be "long and complicated". France: President Emmanuel Macron commented on social media: "The barbaric state has fallen. At last. I pay tribute to the Syrian people, to their courage, to their patience." He added that France would remain committed to security in the Middle East. Germany: Foreign Minister Annalena Baerbock described the end of the Assad regime as "a big relief for millions of people in Syria" while warning that "the country must not fall into the hands of other radicals". Indonesia: The Ministry of Foreign Affairs reported that the Embassy of Indonesia in Damascus attacked by stray bullets from the Syrian Opposition Forces and causing minor damages to the building on 9 December 2024. No casualties and injured reported from the attack.
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.
Cardarine targets PPARδ, a nuclear receptor involved in lipid and energy metabolism. It does not bind the androgen receptor in the way SARMs do.