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.
Last reviewed on 2025-12-15. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
Legal status varies by country. In some places, cardarine is controlled under medicines or psychoactive substances laws; in others, it may be sold with minimal oversight as a research chemical. Customs agencies have intercepted shipments, and several national health agencies have issued warnings about products marketed for bodybuilding or performance enhancement. The lack of a standardized pharmaceutical supply means identity, purity, and contamination levels can differ widely between samples. These factors make cardarine a regulatory and public health concern rather than a conventional prescription 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.
In the fitness and bodybuilding literature, cardarine is frequently discussed as an endurance agent or fat-loss compound, although such claims are not supported by robust clinical evidence. Online descriptions often mix animal data, user anecdotes, and marketing language. Researchers who study PPARδ agonists distinguish between receptor activation in controlled experiments and unsupervised use of unverified products. The latter introduces unknown purity, dose, and interactions, making reported experiences difficult to interpret scientifically.
GW501516 acts as an agonist at peroxisome proliferator-activated receptor delta, a nuclear receptor involved in transcription of genes related to lipid handling and energy use. Activation of PPARδ can shift skeletal muscle toward greater fatty acid oxidation in animal models, which is one reason it drew interest for metabolic disease and exercise research. The exact downstream effects depend on tissue, species, dose, and duration. Human data are sparse, so many proposed benefits remain hypotheses rather than established clinical outcomes.
Laboratory studies have examined GW501516 in cell cultures and rodents for conditions such as dyslipidemia, insulin resistance, and obesity. Some trials in humans were initiated, but development was discontinued after preclinical findings raised concerns about cancer in certain models. Those findings do not prove that the compound causes cancer in people, but they contributed to regulatory caution. Later reviews often describe the evidence as preliminary and insufficient for assessing long-term safety.
| 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 |
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.
Because cardarine is not an approved medicine, no pharmacopeial monograph defines its identity, purity, or storage requirements. Laboratories typically rely on in-house methods and reference standards when testing materials labeled as GW501516. Certificates of analysis may report purity and identity for a specific batch, but their scope varies and they do not guarantee safety or legal status. Independent verification can include high-performance liquid chromatography, mass spectrometry, nuclear magnetic resonance, and elemental analysis. The distinction between research chemical labeling and human use is significant because quality standards and oversight differ.
Cardarine can be detected in biological samples and product materials using liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). The method separates compounds by chromatography and identifies them by mass-to-charge transitions, allowing low-level detection in urine or blood. Sample preparation often involves enzymatic hydrolysis, solid-phase extraction, or protein precipitation. Certified reference materials and isotope-labeled internal standards improve quantification. Detection windows depend on metabolism, matrix, and assay sensitivity, so no single universal window applies.
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.
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.
== History == In 1982 Dr Alan Howard, together with his son Jon, formed the Howard Foundation into which all royalties and profits from worldwide sales of the Cambridge Diet and other intellectual property rights were paid. The Foundation currently focuses on biomedical research and philanthropy. The Foundation sponsors research into human nutrition and conferences on obesity, prostate cancer, creatine, and on macular carotenoids.
Amphetamine-Dextroamphetamine is known to hamper appetite. Amphetamine-Dextroamphetamine is used to treat Attention deficit hyperactivity disorder (ADHD) and is usually under the trade name "Adderall" or "Mydayis". Amphetamine sulfate (also known as amfetamine) – US FDA-approved for the treatment of exogenous obesity under the brand name "Evekeo". Methylphenidate Cocaine Caffeine Glucomannan Leptin Lisdexamfetamine - US FDA approved for the treatment of binge-eating disorder in adults under the brand name "Vyvanse". Methamphetamine hydrochloride – USFDA-approved for the treatment of obesity (as a short-term) under the brand name "Desoxyn". Nicotine Liraglutide as brand name Saxenda Semaglutide (brand name Ozempic/Wegovy) GLP-1 agonist Tirzepatide (Brand Name Mounjaro, Zepbound) Metformin Opiates/opioids such as heroin, morphine, codeine, oxycodone, fentanyl, etc. Anti-obesity medication
Advanced product quality planning (APQP) is a framework of procedures and techniques used to develop products in industry, particularly in the automotive industry. It differs from Six Sigma in that the goal of Six Sigma is to reduce variation but has similarities to Design for Six Sigma (DFSS). According to the Automotive Industry Action Group (AIAG), the purpose of APQP is "to produce a product quality plan which will support development of a product or service that will satisfy the customer." It is a product development process employed by General Motors, Ford, Chrysler, and their suppliers.
Based on its amino acid profile C-5 sterol desaturase appears to have four to five membrane-spanning regions, suggesting that it is a transmembrane protein. C5SD activity has been demonstrated in microsomes from rat tissue, implying that rat enzyme localizes to the endoplasmic reticulum Fluorescence microscopy experiments have shown that in the ciliate Tetrahymena thermophila C5SD localizes to the endoplasmic reticulum and that in S. cerevisiae C5SD localizes to both the endoplasmic reticulum and vesicles. In Arabidopsis thaliana C5SD is located in both the endoplasmic reticulum and lipid particles.
Though an effective antibiotic when all others fail, against extremely drug resistant infections, it has many side effects. including inhibition of monoamine oxidase, and as with other nitrofurans generally, minimum inhibitory concentrations also produce systemic toxicity, resulting in tremors, convulsions, peripheral neuritis, gastrointestinal disturbances, and depression of spermatogenesis. Nitrofurans are recognized by FDA as mutagens/carcinogens, and can no longer be used in food-producing animals in the United States as of 1991. Nitrofurazone Nitrofurantoin Norwich Pharmacal Co. & Others v Customs and Excise Commissioners Peptic ulcers and Helicobacter pylori
Sources: en.wikipedia.org
== Production == The production methods for different isotopes vary, and only those for promethium-147 are given because it is the only isotope with industrial applications. Promethium-147 is produced in large quantities (compared to other isotopes) by bombarding uranium-235 with thermal neutrons. The output is relatively high, at 2.6% of the total product. Another way to produce promethium-147 is via neodymium-147, which decays to promethium-147 with a short half-life. Neodymium-147 can be obtained either by bombarding enriched neodymium-146 with thermal neutrons or by bombarding a uranium carbide target with energetic protons in a particle accelerator. Another method is to bombard uranium-238 with fast neutrons to cause fast fission, which, among multiple reaction products, creates promethium-147. As early as the 1960s, Oak Ridge National Laboratory could produce 650 grams of promethium per year and was the world's only large-volume synthesis facility. Gram-scale production of promethium was discontinued in the U.S. in the early 1980s, but will possibly be resumed after 2010 at the High Flux Isotope Reactor. In 2010, Russia was the only country producing promethium-147 on a relatively large scale.
Benfluorex, sold under the brand name Mediator, is an anorectic and hypolipidemic agent that is structurally related to fenfluramine (a substituted amphetamine). It acts mostly as a prodrug of norfenfluramine. It was fraudulently claimed to improve glycemic control and decrease insulin resistance in people with poorly controlled type-2 diabetes through norfenfluramine acting as a 5-HT2B receptor agonist It was on the market between 1976 and 2009, and is thought to have caused between 500 and 2,000 deaths. It was patented and manufactured by the French pharmaceutical company Servier. However, Servier has wittingly concealed the nature of Benfluorex, so that it would avoid the ban of Fenfluramine-related medications, which were mostly marketed by Servier (Racemic Fenfluramine/Ponderal, Dexfenfluramine/Isomeride) Servier has been found to be aware of the Fenfluramine-structure nature when starting marketing Benfluorex as an anti diabetic. The mechanism of action of Benfluorex was the anoretic property that is shared with the other Fenfluramine-related compounds. In fact, Benfluorex acts as a prodrug to norfenfluramine, a worldwide withdrawn anorectic because of its high incidence of cardiac fibrosis which is completely out of line for treating type 2 diabetes.
The glycerol released by lipase action is phosphorylated by glycerol kinase in the liver (the only tissue in which this reaction can occur), and the resulting glycerol 3-phosphate is oxidized to dihydroxyacetone phosphate. The glycolytic enzyme triose phosphate isomerase converts this compound to glyceraldehyde 3-phosphate, which is oxidized via glycolysis, or converted to glucose via gluconeogenesis.
The Schengen rules do not require any other procedures; thus, the Schengen states are free to regulate further details on the content of the registration forms, and identity documents which are to be produced, and may also require the persons exempted from registration by Schengen laws to be registered. A Schengen state is also permitted to reinstate border controls with another Schengen country for a short period where there is a serious threat to that state's "public policy or internal security" or when the "control of an external border is no longer ensured due to exceptional circumstances". When such risks arise out of foreseeable events, the state in question must notify the European Commission in advance and consult with other Schengen states. Since the implementation of the Schengen Agreement, this provision has been invoked frequently by member states, especially in response to the European migrant crisis.
Sources: en.wikipedia.org
Taking five weeks to record, the sessions ended in December. On February 14, 2007, an announcement was made on the official Rush website that the title of the new album would be Snakes & Arrows. The first single, "Far Cry", was released to North American radio stations on March 12, 2007, and reached No. 2 on the Mediabase Mainstream and Radio and Records Charts.
== Academic career == In 1974, Candace Pert earned a Ph.D. in pharmacology from Johns Hopkins University School of Medicine, where she worked in the laboratory of Solomon Snyder and discovered the brain's opiate receptor. Pert conducted a National Institutes of Health Postdoctoral Fellowship with the Department of Pharmacology at the Johns Hopkins University School of Medicine from 1974 to 1975. She conducted research at the National Institute of Mental Health from 1975 to 1987. In 1983, she became the Chief of the Section on Brain Biochemistry of the Clinical Neuroscience Branch, the only female chief at NIMH. She left to found and direct a private biotech laboratory in 1987. Pert was a research professor in the department of physiology and biophysics at Georgetown University School of Medicine in Washington, D.C. In her latter years, she was with RAPID Pharmaceuticals. In 1997 she published her book Molecules of Emotion. She appeared as one of the experts in Bill Moyers 1993 PBS video production, "Healing and the Mind", and in the 2004 film What the #$*! Do We Know!?. She died on September 12, 2013, in Potomac, Maryland.
==== Genes and proteins expressed in the epidermis ==== About 70% of all human protein-coding genes are expressed in the skin. Almost 500 genes have an elevated pattern of expression in the skin. There are fewer than 100 genes that are specific for the skin, and these are expressed in the epidermis. An analysis of the corresponding proteins show that these are mainly expressed in keratinocytes and have functions related to squamous differentiation and cornification.
==== Detection in biological fluids ==== Methamphetamine and amphetamine are often measured in urine or blood as part of a drug test for sports, employment, poisoning diagnostics, and forensics. Chiral techniques may be employed to help distinguish the source of the drug to determine whether it was obtained illicitly or legally via prescription or prodrug. Chiral separation is needed to assess the possible contribution of levomethamphetamine, which is an active ingredient in some OTC nasal decongestants, toward a positive test result. Dietary zinc supplements can mask the presence of methamphetamine and other drugs in urine.
26 December - 5 January 1970 The SS Badger State under contract to Military Sea Transportation Service and carrying a load of munitions bound for Da Nang had a bomb explode onboard causing a fire. The crew abandoned ship with 29 crewmen killed and the ship drifted before sinking on 5 January.
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.
It binds and activates PPARδ, a nuclear receptor that influences gene expression related to fatty acid metabolism and energy balance. This mechanism has been studied mainly in animals and cell models, not established as a safe human therapy.