This is a working overview of Nuclear receptor, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2026-07-24 and is reviewed periodically as new material appears.
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 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.
| Property | Value | Notes |
|---|---|---|
| IUPAC name | {4-[({4-methyl-2-[4-(trifluoromethyl)phenyl]-1,3-thiazol-5-yl}methyl)sulfanyl]phenoxy}acetic acid | Systematic name for GW501516 |
| CAS Registry Number | 317318-70-0 | Unique identifier for the parent compound |
| Molecular formula | C21H18F3NO3S2 | Includes carbon, hydrogen, fluorine, nitrogen, oxygen, and sulfur |
| Molecular weight | 453.5 g/mol | Approximate value for the neutral form |
| Appearance | White to off-white powder | Typical description for purified laboratory material |
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 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.
Published human data are sparse and mostly come from early-phase trials. Those studies examined short-term changes in lipids, glucose, and exercise capacity, but they were not large enough to establish efficacy or long-term safety. Some animal experiments reported increased running endurance, yet such findings do not prove a performance benefit in people. Anti-doping laboratories detect GW501516 and its metabolites in urine or blood using liquid chromatography-tandem mass spectrometry. Detection windows depend on dose, sample type, and individual metabolism. The method is sensitive enough to identify trace residues in tested samples.
Laboratory handling focuses on identity, purity, and stability. Reference standards are typically stored cold and dry, protected from light, because solutions can degrade over time. Analytical checks may use high-performance liquid chromatography with ultraviolet detection or mass spectrometry. Impurities and related substances can be separated chromatographically and compared with a known standard. Because cardarine is not an approved drug, compendial monographs are absent, and laboratories often rely on in-house methods. Reported purity varies among unregulated products and should not be assumed from a label.
As gold nanoparticles (AuNPs) are further investigated for targeted drug delivery in humans, their toxicity needs to be considered. For the most part, it is suggested that AuNPs are biocompatible, but the concentrations at which they become toxic needs to be determined, and if those concentrations fall within the range of used concentrations. Toxicity can be tested in vitro and in vivo. In vitro toxicity results can vary depending on the type of the cellular growth media with different protein compositions, the method used to determine cellular toxicity (cell health, cell stress, how many cells are taken into a cell), and the capping ligands in solution. In vivo assessments can determine the general health of an organism (abnormal behavior, weight loss, average life span) as well as tissue specific toxicology (kidney, liver, blood) and inflammation and oxidative responses. In vitro experiments are more popular than in vivo experiments because in vitro experiments are more simplistic to perform than in vivo experiments.
=== EC 1.1.2 With a cytochrome as acceptor === EC 1.1.2.1: glycerolphosphate dehydrogenase. As the acceptor is now known, the enzyme has been transferred to EC 1.1.5.3, glycerol-3-phosphate dehydrogenase. EC 1.1.2.2: mannitol dehydrogenase (cytochrome) EC 1.1.2.3: L-lactate dehydrogenase (cytochrome) EC 1.1.2.4: D-lactate dehydrogenase (cytochrome) EC 1.1.2.5: D-lactate dehydrogenase (cytochrome c-553) EC 1.1.2.6: polyvinyl alcohol dehydrogenase (cytochrome) EC 1.1.2.7: methanol dehydrogenase (cytochrome c) EC 1.1.2.8: alcohol dehydrogenase (cytochrome c) EC 1.1.2.9: 1-butanol dehydrogenase (cytochrome c) EC 1.1.2.10: lanthanide-dependent methanol dehydrogenase EC 1.1.2.11: glucoside 3-dehydrogenase (cytochrome c)
Downtown Emergency Service Center (DESC), in Seattle, Washington, operates several Housing First programmes which utilize the harm reduction model. University of Washington researchers, partnering with DESC, found that providing housing and support services for homeless alcoholics costs taxpayers less than leaving them on the street, where taxpayer money goes towards police and emergency health care. Results of the study funded by the Substance Abuse Policy Research Program (SAPRP) of the Robert Wood Johnson Foundation appeared in the Journal of the American Medical Association in April 2009. This first controlled assessment in the U.S. of the effectiveness of Housing First, specifically targeting chronically homeless alcoholics, showed that the programme saved taxpayers more than $4 million over the first year of operation. During the first six months, the study reported an average cost-savings of 53 percent (even after considering the cost of administering the housing's 95 residents)—nearly $2,500 per month per person in health and social services, compared to the per month costs of a wait-list control group of 39 homeless people. Further, despite the fact residents are not required to be abstinent or in treatment for alcohol use, stable housing also results in reduced drinking among people experiencing homelessness who recreationally use alcohol.
Sources: en.wikipedia.org
The earliest humans must have had and passed on knowledge about plants and animals to increase their chances of survival. This may have included knowledge of human and animal anatomy and aspects of animal behavior (such as migration patterns). However, the first major turning point in biological knowledge came with the Neolithic Revolution about 10,000 years ago. Humans first domesticated plants for farming, then livestock animals to accompany the resulting sedentary societies.
Androgens are involved in prostate-related conditions such as benign prostatic hyperplasia (BPH), chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS), and prostate cancer. In BPH, C21 11-oxygenated steroids (pregnanes) have been identified are precursors to androgens. Specifically, steroids like 11β-hydroxyprogesterone (11OHP4) and 11-ketoprogesterone (11KP4) can be converted to 11-ketodihydrotestosterone (11KDHT), an 11-oxo form of DHT with the same potency. These precursors have also been detected in tissue biopsy samples from patients with BPH, as well as in their serum levels. The relationship between steroid serum levels and CP/CPPS suggests that deficiencies in the enzyme CYP21A2 may contribute to the development of this condition. Non-classical congenital adrenal hyperplasia (CAH) resulting from CYP21A2 deficiency is typically considered asymptomatic in men. However, non-classical CAH could be a comorbidity associated with CP/CPPS.
Audit management Fully track and maintain an audit trail Barcode handling Assign one or more data points to a barcode format; read and extract information from a barcode Chain of custody Assign roles and groups that dictate access to specific data records and who is managing them Compliance Follow regulatory standards that affect the laboratory Customer relationship management Handle the demographic information and communications for associated clients Document management Process and convert data to certain formats; manage how documents are distributed and accessed Instrument calibration and maintenance Schedule important maintenance and calibration of lab instruments and keep detailed records of such activities Inventory and equipment management Measure and record inventories of vital supplies and laboratory equipment Manual and electronic data entry Provide fast and reliable interfaces for data to be entered by a human or electronic component Method management Provide one location for all laboratory process and procedure (P&P) and methodology to be housed and managed as well as connecting each sample handling step with current instructions for performing the operation Personnel and workload management Organize work schedules, workload assignments, employee demographic information, training, and financial information Quality assurance and control Gauge and control sample quality, corrective and preventive action (CAPA), data entry standards, and workflow Reports Create and schedule reports in a specific format; schedule and distribute reports to designated parties Time tracking Calculate and maintain processing and handling times on chemical reactions, workflows, and more Traceability Show audit trail and/or chain of custody of a sample Workflows Track a sample, a batch of samples, or a "lot" of batches through its lifecycle
Sources: en.wikipedia.org
No. Major drug regulators have not approved GW501516 for treating any medical condition. Products sold as cardarine are typically unapproved research chemicals or supplements, so their contents and safety are not assured.
It is prohibited by the World Anti-Doping Agency as a hormone and metabolic modulator. Athletes who test positive for GW501516 can face sanctions, including suspensions and loss of results.
Cardarine is a common or trade-style name, while GW501516 is the research code for the same chemical entity. Some sources also use Endurobol or GSK-516. The names refer to the same compound, not distinct drugs.
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.