The short version of nuclear receptor fits in a sentence. The long version — which is the one that helps — is below.
Reviewed 2026-07-10. Anything still debated is marked as such rather than presented as settled.
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.
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.
Cardarine is a common name for GW501516, an investigational compound developed in the 1990s for metabolic conditions. It acts as an agonist at peroxisome proliferator-activated receptor delta, a nuclear receptor involved in lipid and energy metabolism. The compound is frequently mislabeled as a selective androgen receptor modulator, or SARM, but its molecular target is different. GW501516 reached early clinical testing before development was discontinued. It has no approved therapeutic use in any country. The name cardarine is not a formal international nonproprietary name.
Regulatory treatment varies, but cardarine is not approved as a medicine. Sports authorities list GW501516 as a prohibited substance, and it is banned at all times under the World Anti-Doping Agency code. Many countries restrict sales for human consumption, while online vendors market it as a research chemical. Such products may lack purity data, and their actual contents can differ from the label. Purchasing or possessing cardarine may carry legal consequences depending on jurisdiction. The compound is not a dietary supplement ingredient in regulated markets.
Clinical development stopped after rodent studies showed tumors at multiple sites. Whether those findings predict human cancer risk remains an open question, but they led sponsors to discontinue programs. Human safety data are limited to small, short-term studies that were not designed to assess cancer risk. Reported effects in those studies included changes in blood lipids, but the evidence is insufficient for medical use. Long-term consequences of nonmedical use are not well characterized. Questions about dose, duration, and individual susceptibility remain unresolved.
| Property | Value | Notes |
|---|---|---|
| Molecular target | PPAR delta (NR1C2) | Ligand-activated nuclear receptor. |
| Primary tissues studied | Skeletal muscle, liver, adipose | Effects on fatty acid oxidation and energy use. |
| Typical detection matrix | Urine | Used in anti-doping analysis. |
| Common analytical method | LC-MS/MS | Detects parent compound and metabolites. |
| Sport regulatory class | Prohibited at all times | Listed as a metabolic modulator by WADA. |
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.
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 an agonist at the peroxisome proliferator-activated receptor delta, a nuclear receptor that regulates gene expression. Activation shifts transcription toward genes involved in fatty acid uptake, oxidation, and energy expenditure. The compound does not bind the androgen receptor and therefore differs from anabolic steroids and SARMs. In rodent models, this metabolic shift has been linked to increased running endurance and reduced fat accumulation. The exact downstream pathways in humans remain incompletely characterized.
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.
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.
=== Selected articles === Ganzler, K., Salgó, A., & Valkó, K. (1986). Microwave extraction: A novel sample preparation method for chromatography. Journal of Chromatography A, 371, 299–306. Valkó, K., Snyder, L. R., & Glajch, J. L. (1993). Retention in reversed-phase liquid chromatography as a function of mobile-phase composition. Journal of Chromatography A, 656(1–2), 501–520. Valkó, K., Bevan, C., & Reynolds, D. (1997). Chromatographic hydrophobicity index by fast-gradient RP-HPLC: a high-throughput alternative to log P/log D. Analytical Chemistry, 69(11), 2022–2029. Valko, K., Nunhuck, S., Bevan, C., Abraham, M. H., & Reynolds, D. P. (2003). Fast gradient HPLC method to determine compounds binding to human serum albumin. Relationships with octanol/water and immobilized artificial membrane lipophilicity. Journal of Pharmaceutical Sciences, 92(11), 2236–2248. Valkó, K. (2004). Application of high-performance liquid chromatography based measurements of lipophilicity to model biological distribution. Journal of Chromatography A, 1037(1–2), 299–310. Valko, K. (2016) Lipophilicity and biomimetic properties measured by HPLC to support drug discovery. Journal of Pharmaceutical and Biomedical Analysis, (130), 35–54. Valko, K.Ivanova-Berndt, G. Beswick, P. Kindey, M. Ko, D. (2018) Application of biomimetic HPLC to estimate lipophilicity, protein and phospholipid binding of potential peptide therapeutics. ADMET & DMPK 6(2) 162–175.
She said that "This has nothing to do with tension or relations between Delcy Rodriguez and myself," and discussed that the "criminal structure" that has dominated Venezuela for years would eventually dismantle itself. A week later, Trump said he was considering involving Machado in his plans on Venezuela in some way, without specifying which role she would play. On 26 January, after a hearing on Venezuela on the US Senate, Marco Rubio met with Machado. She later said to reporters that a change in Venezuela was coming. Venezuelan TV network Venevisión broadcast Machado message after meeting with Rubio. According to the Venezuelan national press workers union, the state regulator later cut Venevision's access to some satellite TV providers. In an interview of NBC, Delcy Rodríguez said about Machado that "She will have to answer to Venezuela why she called upon a military intervention, why she called upon sanctions to Venezuela, and why she celebrated the actions that took place at the beginning of January." At Machado's request, she met for a second time with Donald Trump in the White House on 6 March to review plans for her trip to come back to Venezuela. In September 2026, Machado's reported about seven failed attempts to enter the country by air and sea, at least three while Delcy Rodríguez was away during a UN General Assembly.
Significant efforts in the mid-20th century helped clarify its nomenclature, stabilising its current name. Although there were challenges to this name in the 1980s, it was confirmed as valid in 2004. More recently, DNA studies suggest that there may be hidden diversity within the species, indicating the need for further taxonomic evaluation. The lichen is used as a spice in Indian cuisine. For this purpose, it is commonly known as black stone flower or kalpasi (among other names). Although nearly tasteless on its own, it releases an earthy fragrance and taste when cooked in with oil or butter.
Sources: en.wikipedia.org
== Historical applications == By 2001, over 175 analytes had been measured using DBS, ranging from acylcarnitines and C-reactive protein to cyclosporine A, cytokines, hepatitis B virus, glucose, and antibodies for over 30 viruses and microorganisms. Other analytes included gentamicin, lipoproteins, prolactin, selenium, trace elements, vitamin A, and zinc protoporphyrin were also measured. In the 20th century, the use of blood and serum collected and dried on a filter paper for serologic testing for syphilis was already reported. Both field and home sample collections were described. The first report of blood absorbed onto filter paper for enzyme measurements was published in 1953. In 1962, Berry explored the use of filter paper urine samples for population-based screening programs. In 1980, an immunochemical test for colorectal cancer screening using fecal occult blood smears on specially treated filter paper was introduced. In 1987, successful extraction of DNA from blood collected on “blotter” paper and dried was first reported by McCabe. The United States can serve as one of the best examples of a widespread usage of DBS. There, DBS is a part nationally-coordinated effort (controlled by the American Center for Disease Control and Prevention) for newborn screening. This programme, named Newborn Screening Quality Assurance Program (NSQAP), ensures that newborns routinely undergo screening tests to detect those with diseases that need an increased medical attention. The NSQAP is based on dried blood spots sampling, where the blood is collected from the newborn's heel.
On 13 December 1904, Hungarian Sándor Just and Croatian Franjo Hanaman were granted a Hungarian patent (No. 34541) for a tungsten filament lamp that lasted longer and gave brighter light than the carbon filament. Tungsten filament lamps were first marketed by the Hungarian company Tungsram in 1904. This type is often called Tungsram-bulbs in many European countries. Filling a bulb with an inert gas such as argon or nitrogen slows the evaporation of the tungsten filament compared to operating it in a vacuum. This allows for greater temperatures and therefore greater efficacy with less reduction in filament life. In 1906, William D. Coolidge developed a method of making "ductile tungsten" from sintered tungsten which could be made into filaments while working for General Electric Company. By 1911 General Electric had begun selling incandescent light bulbs with ductile tungsten wire. In 1913, Irving Langmuir found that filling a lamp with inert gas (nitrogen at first, and later argon) instead of a vacuum resulted in twice the luminous efficacy and reduced bulb blackening. He patented his device on April 18, 1916.
On July 6, 2025, furious that their Acting Grand Master had been arrested, dozens of members of the High Chamber held a large protest in front of the National Masonic Temple in rejection of Filema Duarte's authority to call any session of the High Chamber. The session had been scheduled to occur later that day. However, when they tried to enter the building, the Tyler was joined by three Freemasons who sided with Filema Duarte – Jesús Martínez Frómeta, Raúl Pérez Martín and Rolando Céspedes Mena – who refused the protesters entry to the building. The two sides pushed and shoved. The protestors cried and shouted for Filema Duarte to exit the building, and he did come down to try and meet with them. But Former Grand Master Ernesto Zamora Fernández then, in a video which appeared on Zamora Fernández's Facebook profile, was seen leading a chant of "Out, traitor! Get out!" Filema Duarte retreated back into his office, with the Freemasons still shouting at him that he was a traitor to the Brotherhood and a puppet of the Cuban government. Filema Duarte issued a statement that he had cancelled the session of the High Chamber, in which he also stated that he would not be stepping aside as Grand Master. On Facebook, Zamora Fernández wrote: "This is the face of the dictatorship dressed as the Grand Master of the Cuban Masons, his name: Maikel Filema. He is worse than Agent Collera Vento. Dismissed by the Masons, he clings to power with the support of the government... Your betrayal, your lack of civility, your lack of morality, your ignorance. Your baseness, your lack of ethics.
Sources: en.wikipedia.org
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.
Early-stage trials examined lipid and glucose markers, but the development program was discontinued. Published human results are limited and do not support approved use for any indication. Claims of performance or health benefits remain unproven.
Yes. Laboratories use LC-MS/MS to detect GW501516 and its metabolites in urine. Detection depends on timing and sensitivity, but the substance is banned at all times.
No. Cardarine is GW501516, a PPARδ agonist, while SARMs act on androgen receptors. The two classes are often grouped in informal discussions despite different mechanisms.