A practical reference on Nuclear receptor: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
Reviewed 2026-06-18. Anything still debated is marked as such rather than presented as settled.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Chemical class | PPARδ agonist | Not an anabolic steroid. |
| Common synonyms | GW501516, GW-1516 | Cardarine is an informal name. |
| Appearance | White to off-white powder | Typical for research-grade solid. |
| Solubility class | Poorly soluble in water; soluble in some organic solvents | Such as DMSO or ethanol in laboratory settings. |
| Typical storage temperature | Cool, dry, protected from light | Specific conditions vary by supplier and form. |
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.
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.
=== Splitting of water === The bound metal ion, plus a glutamate-histidine pair, activates and splits a water molecule from the surrounding solution. This generates a hydroxide ion within the active site.
On 12 December, the Ottoman Grand Vizier, Talaat Pasha, gave an interview to the German newspaper Vossische Zeitung that was published on 31 December and subsequently released in the German-Jewish periodical Jüdische Rundschau on 4 January 1918, in which he referred to the declaration as "une blague" (a deception) and promised that under Ottoman rule "all justifiable wishes of the Jews in Palestine would be able to find their fulfilment" subject to the absorptive capacity of the country. This Turkish statement was endorsed by the German Foreign Office on 5 January 1918. On 8 January 1918, a German-Jewish Society, the Union of German Jewish Organizations for the Protection of the Rights of the Jews of the East, was formed to advocate for further progress for Jews in Palestine. Following the war, the Treaty of Sèvres was signed by the Ottoman Empire on 10 August 1920. The treaty dissolved the Ottoman Empire, requiring Turkey to renounce sovereignty over much of the Middle East. Article 95 of the treaty incorporated the terms of the Balfour Declaration with respect to "the administration of Palestine, within such boundaries as may be determined by the Principal Allied Powers". Since incorporation of the declaration into the Treaty of Sèvres did not affect the legal status of either the declaration or the Mandate, there was also no effect when Sèvres was superseded by the Treaty of Lausanne, which did not include any reference to the declaration.
Hydrogen sulfide gas and the hydrosulfide anion are extremely toxic to mammals, due to their inhibition of the oxygen-carrying capacity of hemoglobin and certain cytochromes in a manner analogous to cyanide and azide (see below, under precautions).
=== Tumours === Proteases are associated with cancer progression due to their ability to degrade extracellular matrices, which facilitates invasion and metastasis; these enzymes target a diversity of substrates and favour all steps of tumour production; some proteases have tumour-suppressive effects, associated with more than 30 different enzymes that belong to three distinct protease classes.
When the Atlantic slave trade began, many of the local slave systems began supplying captives for chattel slave markets outside Africa. Although the Atlantic slave trade was not the only slave trade from Africa, it was the largest in volume and intensity. As Elikia M'bokolo wrote in Le Monde diplomatique:
Sources: en.wikipedia.org
=== Types === Inorganic compounds: potassium alum, aluminium hydroxide, aluminium phosphate, calcium phosphate hydroxide Oils: paraffin oil, propolis (only in preclinical studies). Adjuvant 65 (based on peanut oil) was tested in influenza vaccines in the 1970s, but was never released commercially. Freund's incomplete adjuvant is a water-in-oil emulsion, a classical adjuvant. Water-in-oils are generally too reactogenic to be used on humans, however. Squalene is a natural oil made by human bodies. MF59 is a oil-in-water emulsion based on squalene. Bacterial products: killed bacteria of the species Bordetella pertussis, Mycobacterium bovis, toxoids. MPL (Monophosphorylated lipid A) is a modified form of a bacterial lipid A protein that is used in several vaccines. Plant saponins from Quillaia (soap bark tree), soybean and Polygala senega Cytokines: IL-1, IL-2, IL-12 CpG oligonucleotides Combinations: Freund's complete adjuvant (incomplete + dead Mycobacterium), AS01 (combining MPL and Quillaia saponins), Matrix-M (combining Quillaia saponins and two types of fat) Small molecules: TLR7/8 agonists (imidazoquinolines, imidazopyrimidines) Physical methods: radiofrequency heating (only tested in mice), microneedles (only tested in mice)
H2NCO−2 + 2 H2O ⇌ NH+4 + HCO−3 + OH− H2NCO−2 + H2O ⇌ NH+4 + CO2−3 Calcium carbamate is soluble in water, whereas calcium carbonate is not. Adding a calcium salt to an ammonium carbamate/carbonate solution will precipitate some calcium carbonate immediately, and then slowly precipitate more as the carbamate hydrolyzes.
=== Bridging projects === The enolase superfamily contains evolutionarily related enzymes with a (β/α)7β‑barrel (TIM‑barrel) fold which primarily catalyze metal-assisted epimerization/racemization or β-elimination of carboxylate substrates. The Haloacid dehydrogenase superfamily contains evolutionarily related enzymes with a Rossmanoid α/β fold with an inserted "cap" region which primarily catalyze metal-assisted nucleophilic catalysis, most frequently resulting in phosphoryl group transfer. The isoprenoid synthase (I) superfamily contains evolutionarily related enzymes with a mostly all α-helical fold and primarily catalyze trans-prenyl transfer reactions to form elongated or cyclized isoprene products. The Anaerobic Enzymology bridging project will explore radical-dependent enzymology, which allows the execution of unusual chemical transformations via an iron-sulfur cluster cleaving S-Adenosyl methionine (SAM) and producing a radical intermediate, or alternatively, abstraction of a hydrogen from glycine producing a glycyl radical. The superfamilies containing these enzymes are largely unexplored and thus, ripe with the potential for functional discoveries. The acquisition of an anaerobic protein production pipeline coupled with the installation of a Biosafety Level 2 anaerobic chamber for culturing human gut microbes has readied the EFI to pursue anaerobic enzymology.
== Synthesis == The easiest way of synthesizing PVDF is the radical polymerization of vinylidene fluoride (VF2), however, the polymerization is not completely regiospecific. The asymmetric structure of VF2 leads to the orientation isomers during the polymerization. The configuration of the monomer in the chain can be either "head to head" or "head to tail".
Sources: en.wikipedia.org
Cardarine is commonly known as GW501516 or GW-1516. These names refer to the same synthetic compound. It is not a brand-name approved medicine.
No, cardarine is not a steroid. It is classified as a PPARδ agonist. Its structure and receptor target differ from anabolic steroids.
No regulatory agency has approved cardarine as a medicine. It was investigated in early research but development was discontinued. It is not available as a prescription drug.
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.