If you have been reading about Prohibited substance and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Last reviewed on 2025-11-18. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
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.
| 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. |
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.
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.
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.
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.
Mixed connective tissue disease (MCTD) is a systemic autoimmune disease that shares characteristics with at least two other systemic autoimmune diseases, including systemic sclerosis (Ssc), systemic lupus erythematosus (SLE), polymyositis/dermatomyositis (PM/DM), and rheumatoid arthritis. The idea behind the "mixed" disease is that this specific autoantibody is also present in other autoimmune diseases such as systemic lupus erythematosus, polymyositis, scleroderma, etc. MCTD was characterized as an individual disease in 1972 by Sharp et al., and the term was introduced by Leroy in 1980. Some experts consider MCTD to be the same as undifferentiated connective tissue disease, but other experts specifically reject this idea because undifferentiated connective tissue disease is not necessarily associated with serum antibodies directed against the U1-RNP. Furthermore, MCTD is associated with a more clearly defined set of signs and symptoms.
structural formula A graphical representation of the molecular structure and geometry of a particular chemical compound, showing how the atoms are arranged in real, three-dimensional space. Chemical bonding within the molecule is also shown, either implicitly or explicitly. When known with certainty, structural formulas are very useful because they allow chemists to visualize the molecules and the structural changes that occur in them during chemical reactions.
==== Judiciary ==== The U.S. federal judiciary consists primarily of the U.S. Supreme Court, the U.S. courts of appeals, and the U.S. district courts. Judges for these courts are appointed under Article III: They are nominated by the president, confirmed by the Senate, and hold office subject to good behavior (generally resulting in life tenure). To limit outside interference, their compensation may not be reduced while they remain in office. Congress has also created Article I courts under its legislative powers; unlike Article III judges, whose tenure and compensation are protected by the Constitution, Article I judges generally serve fixed statutory terms. Federal district courts are the primary trial courts of the federal judiciary and hear civil and criminal cases within their jurisdiction, including cases arising under federal statutes, the Constitution, or international treaties. Decisions of federal district courts may generally be challenged to a federal court of appeals. The U.S. judicial system's 12 regional circuits divide the country into geographic regions for appellate purposes, while the Federal Circuit has nationwide jurisdiction over specified types of cases. The Supreme Court is the highest court in the federal judiciary. It has both original and appellate jurisdiction and exercises judicial review, under which it may hold laws or governmental actions unconstitutional. On average, the Supreme Court receives about 7,000 petitions for writs of certiorari each year but grants review in about 80 cases.
== Detection of citrullinated peptides and proteins == Citrullinated peptides and proteins can be detected using antibodies targeting the citrullinated residues, or detected using mass spectrometry-based proteomics technologies. Citrullination of arginine results in a monoisotopic mass increase of +0.984016 Da, which can be measured with mass spectrometry. The mass shift is close to the mass difference between the different peptide isotopes of +1.008665 which can be mistaken for a citrullinated peptide, especially on low-resolution instruments. However, this is less of an issue with modern high resolution/high accuracy mass spectrometers. Furthermore, the mass shift is identical to the mass shift caused by deamidation of the amino acid asparagine or glutamine side chain, which are common modifications. Citrulline residues can be chemically modified with butanedione or by biotinylation prior to analysis, leading to a different mass shift, and this strategy has successfully been used to facilitate identification by mass spectrometry. Another approach is to utilize the neutral loss of isocyanic acid (HNCO) from citrulline residues when submitted to low energy collision induced dissociation fragmentation in mass spectrometers. The loss causes a mass shift of −43.0058 Da, which can be utilized by mass spectrometers to predominantly select citrullinated peptides for fragmentation (sequencing). Finally, the loss of positive charge at physiological pH caused by citrullination can be utilized. Prior to bottom-up proteomics analysis, proteins are enzymatically cleaved into peptides.
=== Repulsion forces === Because nuclei are all positively charged, they strongly repel one another. Normally, in the absence of a catalyst such as a muon, very high kinetic energies are required to overcome this charged repulsion. Extrapolating from known fusion rates, the rate for uncatalyzed fusion at room-temperature energy would be 50 orders of magnitude lower than needed to account for the reported excess heat. In muon-catalyzed fusion there are more fusions because the presence of the muon causes deuterium nuclei to be 207 times closer than in ordinary deuterium gas. But deuterium nuclei inside a palladium lattice are further apart than in deuterium gas, and there should be fewer fusion reactions, not more. Paneth and Peters in the 1920s already knew that palladium can absorb up to 900 times its own volume of hydrogen gas, storing it at several thousands of times the atmospheric pressure. This led them to believe that they could increase the nuclear fusion rate by simply loading palladium rods with hydrogen gas. Tandberg then tried the same experiment but used electrolysis to make palladium absorb more deuterium and force the deuterium further together inside the rods, thus anticipating the main elements of Fleischmann and Pons' experiment. They all hoped that pairs of hydrogen nuclei would fuse together to form helium, which at the time was needed in Germany to fill zeppelins, but no evidence of helium or of increased fusion rate was ever found.
Sources: en.wikipedia.org
Human-animal chimeras include humans having undergone non-human to human xenotransplantation, which is the transplantation of living cells, tissues or organs from one species to another. Patient derived xenografts are created by xenotransplantation of human tumor cells into immunocompromised mice, and is a research technique frequently used in pre-clinical oncology research.
=== Antibacterial activity === Certain antimicrobial biomolecules found in the spider silk of P. phalangioides are able to elicit an inhibitory effect on drug-resistant human pathogens including gram-positive bacteria L. monocytogenes, gram-negative E. coli, Staphylococcus aureus, Bacillus subtilis, and Pseudomonas aeruginosa. More generally, researchers are hoping that the anti-microbial biomolecules of this spider silk could serve as a natural anti-microbial agent in the future against a host of infectious bacterial diseases that are resistant to antibiotics.
== Research == A 2015 trial found nicotinamide to reduce the rate of new nonmelanoma skin cancers and actinic keratoses in a group of people at high risk for the conditions. Nicotinamide has been investigated for many additional disorders, including treatment of bullous pemphigoid and nonmelanoma skin cancers. Nicotinamide may be beneficial in treating psoriasis. There is tentative evidence for a potential role of nicotinamide in treating acne, rosacea, autoimmune blistering disorders, ageing skin, and atopic dermatitis. Nicotinamide also inhibits poly(ADP-ribose) polymerases (PARP-1), enzymes involved in the rejoining of DNA strand breaks induced by radiation or chemotherapy. ARCON (accelerated radiotherapy plus carbogen inhalation and nicotinamide) has been studied in cancer. Research has suggested nicotinamide may play a role in the treatment of HIV.
== Variations == Other boneless chuck cuts include the chuck eye (boneless cuts from the center of the roll, sold as Delmonico steak or chuck eye steak), chuck fillet (sold as chuck tender steak or mock tender steak), cross-rib roast (sold as cross-rib pot roast, English roast, or "the bread and butter cut"), top blade steak or chicken steak, under-blade steak (otherwise known as the "Denver cut"), shoulder steak and shoulder roast, and arm steak and arm roast. The average meat market cuts thick and thin chuck steaks (often sold as chuck steak or chuck steak family pack) from the neck and shoulder, but some markets also cut it from the center of the cross-rib portion. Short ribs are cut from the lip of the roll. Some meat markets will sell cross-rib pot roast under the generic name pot roast. The difference between a pot roast and a cross-rib pot roast is the vertical line of fat separating the two types of chuck meat; the cross-rib pot roast contains the line of fat. This is what creates richness of flavor in the roast.
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.
It binds to and activates PPAR delta, a nuclear receptor that controls expression of genes related to fatty acid oxidation. This mechanism can alter energy metabolism in animal models. It is not a direct stimulant or fat-burning enzyme.