GW501516 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 2025-09-29. Where a claim depends on a specific study, the study is described rather than over-claimed.
Laboratory studies indicate that GW501516 activates PPARδ, a nuclear receptor involved in fatty acid oxidation and energy metabolism. In rodent experiments, treated animals often showed increased endurance and reduced fat mass. These effects were observed under controlled conditions and do not establish safe or effective use in humans. The exact dose-response relationship in humans remains poorly characterized. Species differences in metabolism can affect how results translate across animals and people.
Safety concerns emerged from long-term animal studies. In rodents given the compound for extended periods, researchers found an increased incidence of certain cancers, including liver and bladder tumors. These findings contributed to the discontinuation of clinical development. Whether similar risks apply to short-term or low-level exposure in humans is not established, and controlled human safety data are limited. The relevance of high-dose rodent carcinogenicity findings to human use remains a subject of debate.
Human trials of GW501516 were small and short in duration. They examined lipid levels, glucose handling, and other metabolic markers, but the programs were halted after the animal cancer findings. No approved therapeutic product exists, and published human data are insufficient for establishing long-term safety. Reports of use for athletic performance come mainly from non-clinical settings and cannot be verified through controlled trials. Independent testing of products sold as cardarine has found inconsistent purity and labeling.
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 |
|---|---|---|
| Primary target | PPARδ (NR1C2) | Nuclear receptor involved in lipid metabolism |
| Preclinical effect | Increased fatty acid oxidation | Observed in rodent studies |
| Key safety signal | Tumors in rodents after long-term exposure | Contributed to halted clinical development |
| Human trial status | No approved product; development stopped | Limited short-term metabolic data |
| Sport regulatory status | Prohibited at all times | WADA hormone and metabolic modulators class |
Early clinical research explored GW501516 for lipid disorders, obesity, and diabetes. Some short-term human studies reported changes in HDL cholesterol, LDL cholesterol, and triglycerides. The development program was discontinued after rodent studies showed dose-dependent tumor formation in multiple tissues, including liver, bladder, stomach, and skin. These findings raised concerns about long-term cancer risk in humans. Because human exposure data are limited, the clinical significance of the rodent tumors remains uncertain.
Literature on cardarine often separates receptor pharmacology from toxicology. Mechanistic papers describe PPARδ activation and gene expression changes, while safety assessments focus on carcinogenicity and species differences. Questions remain about whether rodent tumors arise through PPARδ-dependent or off-target mechanisms. Another open area is how human metabolism and exposure compare with those in animal studies. Analytical methods such as liquid chromatography–mass spectrometry are used to confirm identity in biological and product samples.
Cardarine is a synthetic compound also known as GW501516, GW-501516, and sometimes endurobol. It was developed as a selective agonist of peroxisome proliferator-activated receptor delta, a nuclear receptor involved in fatty acid oxidation and energy metabolism. The compound was studied in preclinical models for metabolic and cardiovascular conditions, but it did not become a marketed human medicine. In regulatory and anti-doping contexts, it is treated as a prohibited substance rather than a licensed medicine.
The pharmacological interest in cardarine centers on PPARδ activation and its downstream effects on lipid handling and mitochondrial function. In animal studies, PPARδ agonists have been associated with changes in exercise endurance and fatty acid utilization, though results vary by model and protocol. Human data remain sparse, and the absence of large controlled trials limits conclusions about efficacy. Researchers often describe the compound as a tool for probing PPARδ biology rather than a proven therapeutic agent.
Safety discussions about cardarine frequently cite rodent carcinogenicity findings reported in the 2000s. In those studies, treated animals developed tumors at multiple sites, leading sponsors to discontinue clinical development. The relevance of these findings to humans has not been resolved, but they are a major reason the compound is not approved. Current literature emphasizes uncertainty about long-term effects and the risks of unregulated use. Regulators and health agencies have not established a safe human exposure level.
The domesticated saffron crocus, Crocus sativus, is an autumn-flowering perennial plant unknown in the wild. It possibly descends from the eastern Mediterranean autumn-flowering Crocus cartwrightianus which is also known as "wild saffron" and is native to mainland Greece, Euboea, Crete, Skyros and some islands of the Cyclades. The similar species C. thomasii and C. pallasii were considered as other possible ancestors. As a genetically monomorphic clone incapable of seed production, it was slowly propagated by humans throughout much of Eurasia. Various origins have been suggested for saffron, including Iran, Mesopotamia, Kashmir and Greece.
In the Romanian general election of 1946, the Romanian Communist Party (PCR) employed widespread intimidation tactics and electoral fraud to obtain 80 percent of the vote and, thereafter, eliminated the role of the centrist parties and forced mergers, the result of which was that, by 1948, most non-Communist politicians were either executed, in exile or in prison. In the December 1945 Albanian election, the only effective ballot choices were those of the communist Democratic Front (Albania), led by Enver Hoxha. In 1946, Albania was declared the People's Republic of Albania. The defining characteristic of the Stalinist communism implemented in Eastern Bloc states was the unique symbiosis of the state with society and the economy, resulting in politics and economics losing their distinctive features as autonomous and distinguishable spheres. Initially, Stalin directed systems that rejected Western institutional characteristics of market economies, democratic governance (dubbed "bourgeois democracy" in Soviet parlance) and the rule of law subduing discretional intervention by the state. They were economically communist and depended upon the Soviet Union for significant amounts of materials. While in the first five years following World War II, massive emigration from these states to the West occurred, restrictions implemented thereafter stopped most East-West migration, except that under limited bilateral and other agreements.
=== Decoration (1808–1955) === The original Palmes académiques was instituted by Napoleon on 17 March 1808. In this sense, it shares its origins with the Legion of Honour which Napoleon had established shortly before. Palmes académiques was established to decorate people associated with the university, including high schools (lycées). It was not an order as such, but a title of honour identifiable by its insignia sewn on the recipients' costumes. It was bestowed only upon teachers or professors. The original decoration included three classes:
Sources: en.wikipedia.org
=== Norway === Reports from Norway have shown carisoprodol has addictive potential as a prodrug of meprobamate and/or potentiator of hydrocodone, oxycodone, codeine, and similar drugs. In May 2008 it was taken off the market in Norway.
== External links == Clinical trial number NCT02896192 for "Setmelanotide for the Treatment of Early-Onset POMC Deficiency Obesity" at ClinicalTrials.gov Clinical trial number NCT03287960 for "Setmelanotide for the Treatment of LEPR Deficiency Obesity" at ClinicalTrials.gov
== Mechanical properties == The ongoing research has shown that mechanical properties can vary significantly in nanomaterials compared to bulk material. Nanomaterials have substantial mechanical properties due to the volume, surface, and quantum effects of nanoparticles. This is observed when the nanoparticles are added to common bulk material, the nanomaterial refines the grain and forms intergranular and intragranular structures which improve the grain boundaries and therefore the mechanical properties of the materials. Grain boundary refinements provide strengthening by increasing the stress required to cause intergranular or transgranular fractures. A common example where this can be observed is the addition of nano Silica to cement, which improves the tensile strength, compressive strength, and bending strength by the mechanisms just mentioned. The understanding of these properties will enhance the use of nanoparticles in novel applications in various fields such as surface engineering, tribology, nanomanufacturing, and nanofabrication. Techniques used: Steinitz in 1943 used the micro-indentation technique to test the hardness of microparticles, and now nanoindentation has been employed to measure elastic properties of particles at about 5-micron level. These protocols are frequently used to calculate the mechanical characteristics of nanoparticles via atomic force microscopy (AFM) techniques. To measure the elastic modulus; indentation data is obtained via AFM force-displacement curves being converted to force-indentation curves.
=== 2016–2025: Hayden leadership === Appointed in 2016 by President Barack Obama, Carla D. Hayden was sworn in as the fourteenth librarian of Congress on September 14, 2016. She is the first professional librarian to hold the post since 1974, holding a Ph.D. in library science from the University of Chicago. She was the CEO of Enoch Pratt Free Library in Baltimore, Maryland, from 1993 until 2016, and president of the American Library Association (ALA) from 2003 to 2004. She also is the first woman and the first African American to hold the position. She continued the work of digitizing as much as possible of the collection and of expanding electronic access to the collection. She initiated programs to modernize the library, expand access from rural areas, and expanding the infrastructure and technological capacity of the library and assessment of her leadership of the library by the community reflects her expressed goals. The Association of Research Libraries noted Hayden's transformation of the library "into a more open, accessible, and celebrated U.S. institution, while reaffirming its role as the people’s library". The American Library Association characterized Hayden as a "wise and faithful steward of the Library of Congress – the library she has called our 'national treasure'".
Sources: en.wikipedia.org
For example, γδ T cells express a T-cell receptor comprising γ and δ chains instead of the α and β chains that conventional T cell receptors use, and they are able to recognize antigen without the need for presenting it on MHC proteins (though some have shown the ability to recognize MHC-presented antigens), instead having a mode of recognition that resembles that of antibodies, or recognizing phosphoantigens (antigens that are phosphorylated) through butyrophilin. Mucosa-associated invariant T cells (MAIT) cells recognize ligands presented by the MHC-related protein MR1, which presents metabolites of riboflavin, pyridoxine, and folates. NKT cells recognize glycolipid antigens presented on CD1d, most prominently α-galactosylceramide. In contrast to T cell receptors, antibodies can recognize any type of molecule at virtually any size and can recognize either linear or conformational epitopes (the amino acids that comprise an epitope do not need to be next to each other in the primary structure but do need to be near one another when the protein is folded). At the molecular level, an antigen can be characterized by its ability to bind to an antibody's paratopes. Different antibodies have the potential to discriminate among specific epitopes present on the antigen surface.
== History == Because smallpox is eradicated, the effectiveness of brincidofovir was studied in animals infected with viruses that are closely related to the variola virus. Effectiveness was determined by measuring animals' survival at the end of the studies. Safety information to support approval of brincidofovir was derived from clinical trials of the drug for a non-smallpox indication, primarily from patients who received hematopoietic stem cell transplants. The U.S. Food and Drug Administration (FDA) granted the application for brincidofovir priority review, fast track, and orphan drug designations. The FDA approved brincidofovir under the agency's Animal Rule, which allows findings from adequate and well-controlled animal efficacy studies to serve as the basis of an approval when it is not feasible or ethical to conduct efficacy trials in humans.
==== Philanthropy ==== As chairman emeritus of Ferring, Paulsen is a founding sponsor of The Peptide Therapeutics Foundation. He has contributed to the opening of several fertility clinics throughout Russia to help solve its demographics problem. He has donated approximately $40 million to the Museum Kunst der Westküste (Museum of West Coast Art). He has also substantially contributed to the Salk Institute in San Diego, California, Bhutan's Royal Textile Academy and the South Georgia Heritage Trust in Scotland.
Sources: en.wikipedia.org
Rodent studies reported increased endurance and fat oxidation after GW501516 exposure. Long-term studies also found higher rates of some tumors, which led to halted development.
Small short-term human trials examined metabolic markers such as lipids and glucose. The trials did not continue after rodent cancer findings, so long-term human safety is unknown.
Controlled human trials have not established a performance benefit. Anecdotal reports exist, but they are not reliable evidence.
Cardarine targets PPARδ, a nuclear receptor involved in lipid and energy metabolism. It does not bind the androgen receptor in the way SARMs do.