This is a working overview of nuclear receptor, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2026-02-15 and is reviewed periodically as new material appears.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Common synonyms | GW501516; GW-1516; endurobol | GW501516 is the research code |
| Drug class | PPARδ agonist | Not a selective androgen receptor modulator |
| Molecular formula | C21H18F3NO3S2 | Established chemical formula |
| Molar mass | 453.5 g/mol | Calculated from the formula |
| Regulatory status | Prohibited in sport; not approved as medicine | Status varies by country |
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.
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 binds and activates PPARδ, a nuclear receptor that influences transcription of genes involved in fatty acid oxidation and energy use. Activation shifts some metabolic pathways in preclinical models, which is why the compound has been studied for lipid disorders and exercise-related endpoints. The exact downstream effects in humans are incompletely mapped. PPARδ is expressed in many tissues, including skeletal muscle, liver, and adipose tissue, so broad activation may have varied consequences. Researchers continue to examine how selective or partial activation might alter the balance between benefits and risks.
Published human data are sparse and mostly come from early-phase trials. Those studies examined short-term changes in lipids, glucose, and exercise capacity, but they were not large enough to establish efficacy or long-term safety. Some animal experiments reported increased running endurance, yet such findings do not prove a performance benefit in people. Anti-doping laboratories detect GW501516 and its metabolites in urine or blood using liquid chromatography-tandem mass spectrometry. Detection windows depend on dose, sample type, and individual metabolism. The method is sensitive enough to identify trace residues in tested samples.
Laboratory handling focuses on identity, purity, and stability. Reference standards are typically stored cold and dry, protected from light, because solutions can degrade over time. Analytical checks may use high-performance liquid chromatography with ultraviolet detection or mass spectrometry. Impurities and related substances can be separated chromatographically and compared with a known standard. Because cardarine is not an approved drug, compendial monographs are absent, and laboratories often rely on in-house methods. Reported purity varies among unregulated products and should not be assumed from a label.
It was first synthesised in 1811 by Pierre Louis Dulong, who lost three fingers and an eye to its explosive tendencies. As a dilute gas it is less dangerous and is thus used industrially to bleach and sterilise flour. Nitrogen tribromide (NBr3), first prepared in 1975, is a deep red, temperature-sensitive, volatile solid that is explosive even at −100 °C. Nitrogen triiodide (NI3) is still more unstable and was only prepared in 1990. Its adduct with ammonia, which was known earlier, is very shock-sensitive: it can be set off by the touch of a feather, shifting air currents, or even alpha particles. For this reason, small amounts of nitrogen triiodide are sometimes synthesised as a demonstration to high school chemistry students or as an act of "chemical magic". Chlorine azide (ClN3) and bromine azide (BrN3) are extremely sensitive and explosive. Two series of nitrogen oxohalides are known: the nitrosyl halides (XNO) and the nitryl halides (XNO2). The first is very reactive gases that can be made by directly halogenating nitrous oxide. Nitrosyl fluoride (NOF) is colourless and a vigorous fluorinating agent. Nitrosyl chloride (NOCl) behaves in much the same way and has often been used as an ionising solvent. Nitrosyl bromide (NOBr) is red. The reactions of the nitryl halides are mostly similar: nitryl fluoride (FNO2) and nitryl chloride (ClNO2) are likewise reactive gases and vigorous halogenating agents.
=== Age-related differences === While the amino acid scores for PDCAAS and DIAAS are based on toddler requirements (1–3 year olds), the essential amino acid requirements differ for adults and infants. The most demanding essential amino acid requirements are for infants; when children become adults, they need lower proportions of essential amino acids. This also means that many of the vegan protein sources that are limited in one or more essential amino acids, are actually less deficient in essential amino acids for adults, perhaps not deficient at all. Old age and pregnancy also change amino acid requirements, because of the necessity of supporting a fetus or slowing the loss of muscle due to age. The essential amino acid requirements for infants are based on the essential amino acid proportions in human breast milk.
In autumn 1981 he visited Liverpool again, this time with a thirty-strong task force of representatives of local employers and civil servants (unusually for the time, drawn from different departments – DOE, DTI and Employment, but not the Home Office this time – Heseltine had been pushing for greater cooperation between departments since the setting up of the European Space Agency in 1973). For the next fifteen months he visited Liverpool for a day almost every week, refusing police protection and often driving himself, persuading business and local government to work together. Colette Bowe, a DTI official who was deputy director of the task force, recorded that Heseltine was the most effective minister she had ever seen at getting the official machine to do his bidding through a mixture of charm and tough questions.
Sources: en.wikipedia.org
Directed by Sheila Hayman, made by Uden Associates 8 November Rebuilding Berlin, how German telecommunication and electrical engineers found great difficulty in connecting the infrastructure and technology of East and West Berlin, which were largely totally incompatible, and why the two technological systems were so different; East and West Germany were founded in 1953; the trains in East (Deutsche Reichsbahn or DR) and West Germany ran on electric motors that worked in opposite ways; Erich Kratky of Berliner Verkehrsbetriebe (former West Berlin Public Transport) and how East Berlin drivers had 60% of those in West Berlin; Mahlow station, on the S2 line on the Berlin S-Bahn, was completely rebuilt in 1991, opening on 31 August 1992; before 1989, West Berlin could not connect to any neighbouring electrical power networks, so had to make all of its own power itself, by nine power stations; in 1992 West Berlin could not make enough electrical power;Jürgen Beyer of the East Berlin Electricity Board; in 1992 East and West Germany could not connect their electricity systems together; Klaus Krämer of the West Berlin Electricity Board, and how East German load frequency control (LFC) was not good enough for West Germany; East German power stations were polluting; Müggelsee in East Berlin; East Berlin had natural gas - from Russia - but West Berlin did not have natural gas, and had to produce its own gas from processing, and there were many more gas leaks in East Berlin, run by the Berlin Gas Board, and British Gas plc was installing most of the new plastic gas mains in East Berlin; one fifth of housing in East Berlin was uninhabitable, due to lack of renovation and unsafe electrical wiring; much housing in East Berlin did not have any bathrooms; the post system in East Berlin was three times slower than West Berlin, as it was all sorted by hand, and mail hand to be sent in standard envelopes only, in East Germany - the two post systems were incompatible, and East and West Germany had totally different postcode systems, although both had four digits, so a letter was put in front of each Deutsche Post postcode, to show if it was an East or West German postcode; in 1952, telephone connections between East and West Germany were stopped, but four lines were installed in 1972; the East German telephone exchanges were all mechanical, and could not transmit any digital communications; one in ten people in East Berlin had a phone - telecommunications in East Berlin were hopeless and expensive; in 1992 Deutsche Telekom connected East and West Berlin, and the price would be a local call, not the price of an international call, under the phrase Wir schaffen Verbingdungen; not only were East German telecommunications often impossible, but the Stasi secret police were listening in to most calls; Rudolf Reichel of the former East German Economic Institute; science research in East Germany had been greatly restricted; Volker Hassemer; East Germans viewed West Germans as selfish, and West Germans viewed East Germans as backward. Narrated by Su-Lin Looi, directed by Cosima Dannoritzer, produced by Karl Sabbagh, made by Skyscraper Productions 15 November 21st Century Jet, how the Boeing 777 moved from the drawing board to manufacture in 1992, with the innovative new method called CATIA; the Boeing 777 was the largest jet aircraft to have been developed mostly by computer, with assembly beginning in January 1993; there were 10,000 people in the 777 programme, who met the managers in a weekly meeting; meeting the needs of Robert Crandall of American Airlines, and competition from the new Airbus A340; parts of the tail were built in Australia; the nose cone and flaps were made in Italy; the landing gear was made in Canada, the US, and France; parts of the wing ribs and passenger doors were made in Japan; the nose landing gear door was made in Belfast; some of the electronics was made in England; there were about 230 design teams, from different manufacturers; the CATIA system was a digital mockup; Thomas Gaffney, head of passenger doors; Henry Shomber, one of the chief engineers; John Roundhill, a chief project engineer; United Airlines placed the first order, which started the project; Al Tyler of Aerospace Technologies of Australia (ASTA), who made the 777 rudder - the company became Boeing Australia; John King, Baron King of Wartnaby of British Airways visits to look at legroom for the new 777. Narrated by Simon Prebble, directed by Karl Sabbagh, made by Skyscraper Productions 22 November The Puzzle of HIV, scientists after ten years did not understand how HIV worked; immunologists Anthony Fauci and Max Essex; Angus Dalgleish of St George's, University of London; virologist Stephen S. Morse, and the origination of viruses, and how most pandemics originated in China; Stella Knight of the MRC, and dendritic cells, researched by Brigid Balfour; French immunologist Jean-Claude Ameisen of the Pasteur Institute of Lille; virologist Jonas Salk; Claude Nicolau, and the CD4 glycoprotein. Narrated by Scottish actress Sandra Clark, directed by Nigel Maslin, produced by Chris Haws, made by InCA Productions 29 November The Alpha Link, much of medical understanding of radiation protection and health comes from what occurred in Japan in August 1945. Martin Gardner (1940–93), an epidemiologist, and Professor of Medical Statistics at the University of Southampton, thought that health was affected by working in a nuclear power station, which the British nuclear industry vehemently would not believe. Directed by Vivienne King, made by Box Productions 6 December Toying with the Future, about electronic children's toys, visiting Ocean Software in Manchester; Brian Sutton-Smith of the University of Pennsylvania, and how toys were small replicas of large world events; Eugene F. Provenzo of the University of Miami and how the culture of childhood began in the early 1700s, and how German Friedrich Fröbel developed educational toys in the early 1800s, but it often lacked fun; Meccano Ltd sets, developed by Frank Hornby, launching the international Meccano Guild network of children's mechanical clubs in 1919, publicised by the Meccano Magazine; Richard Gregory, neuropsychologist at the University of Bristol, and his Exploratory Hands-on Science Centre, which closed in 1999, replaced by We the Curious in 2000; toy designer Patrick Rylands; Gary Bracey of Ocean Software; Keith Tinman, computer game musician; Elizabeth Curran of GameTek; Ocean Software designers Ray Coffey, James Higgins and Dawn Drake. Directed by Christopher Rawlence, produced by Debra Hauer, made by Rawlence Hauer Productions 13 December The Elements, a repeat of the 20 October 1991 episode 20 December E.T. Please Phone Earth, about the SETI Institute, with Prof Philip Morrison, a professor of physics at MIT, who played a starring if not dangerous role in the Manhattan Project; Jill Tarter at the Hat Creek Radio Observatory in California; Dr John Billingham, a British medical doctor at the Ames Research Center in California; Prof Antony Hewish of the University of Cambridge, who discovered pulsars in 1967; Frank Drake, and his work at the National Radio Astronomy Observatory in Green Bank, West Virginia; Barney Oliver of SETI; David Blair of the University of Western Australia; Paul Horowitz of Harvard University; the Ohio State University Radio Observatory (known as Big Ear) and its 1977 Wow! signal; Jack Cohen; chemist Stanley Miller and his 1953 experiment; blind SETI investigator Kent Cullers; and biologist Jared Diamond from UCLA. Jointly made with ABC of Australia, narrated by Heather Couper, directed by Richard Smith, produced by Stuart Carter, made by Pioneer Productions
== Early life == Darshan Ranganathan was born as Darshan Markan on 4 June 1941 to Vidyavati Markan and Shanti Swarup in Delhi. She was educated in Delhi and received a Ph.D. in chemistry from Delhi University in 1967. First hired as a lecturer, she became head of the Chemistry Department at Miranda College, Delhi, and went on to receive an 1851 Research Fellowship from the Royal Commission for the Exhibition of 1851, to enable her to conduct postdoctoral work at Imperial College London with Professor D.H.R. Barton.
From 1928 to 1932, Albert Szent-Györgyi and Joseph L. Svirbely's Hungarian team, and Charles Glen King's American team, identified the anti-scorbutic factor. Szent-Györgyi isolated hexuronic acid from animal adrenal glands, and suspected it to be the antiscorbutic factor. In late 1931, Szent-Györgyi gave Svirbely the last of his adrenal-derived hexuronic acid with the suggestion that it might be the anti-scorbutic factor. By the spring of 1932, King's laboratory had proven this, but published the result without giving Szent-Györgyi credit for it. This led to a bitter dispute over priority. In 1933, Walter Norman Haworth chemically identified the vitamin as l-hexuronic acid, proving this by synthesis in 1933. Haworth and Szent-Györgyi proposed that L-hexuronic acid be named a-scorbic acid, and chemically l-ascorbic acid, in honor of its activity against scurvy. The term's etymology is from Latin, "a-" meaning away, or off from, while -scorbic is from Medieval Latin scorbuticus (pertaining to scurvy), cognate with Old Norse skyrbjugr, French scorbut, Dutch scheurbuik and Low German scharbock. Partly for this discovery, Szent-Györgyi was awarded the 1937 Nobel Prize in Medicine, and Haworth shared that year's Nobel Prize in Chemistry. In 1957, J. J. Burns showed that some mammals are susceptible to scurvy as their liver does not produce the enzyme l-gulonolactone oxidase, the last of the chain of four enzymes that synthesize vitamin C. American biochemist Irwin Stone was the first to exploit vitamin C for its food preservative properties.
Early surgical techniques like iridectomy and fistulating methods have recently been supplemented by less invasive procedures like small implants, a range of options now widely called MIGS (micro-invasive glaucoma surgery).
Sources: en.wikipedia.org
However, new kits such as "NETSPOT" for more rapidly preparing Ga-68 edotreotide or DOTATATE from Ga-68(III) ions have increased the flexibility of sourcing of this radiopharmaceutical for Ga-68 endocrine receptor (octreotide) scans. With NETSPOT the preparation of the Ga-68 DOTATATE is immediate once the Ga-68 has been acquired from the generator and mixed with the reagent.
=== Distribution === The drug is distributed rapidly and widely to most tissues and fluids, including sputum, pleural fluid, peritoneal fluid, interstitial fluid, bile, aqueous humor, reproductive organs, and bone; highest concentrations occur in pleural fluid, interstitial fluid, peritoneal fluid, and reproductive organs; low concentrations occur in CSF; it crosses the placenta, and enters breast milk
==== Historiography ==== Liu Wenhui retains a positive reputation in Chinese historiography, including a 2022 study by Wang Haibing, which credits his governance for promoting regional economic development and maintaining national unity. One of the main accounts of Liu Wenhui's life, a 1990 biography by Peng Dixian and Shu Guofan, is in itself written by authors who had directly participated in the events surrounding his defection and contact with the Communist Party (and more generally, the communist revolution.) Peng and Shu's biography generally characterizes Liu as a progressive and patriotic reformer, overcoming his warlord past to embrace the communist cause. Here, they assert that Liu's later alignment with the communists was the natural conclusion of his political evolution, and that his conviction towards the Communist Party became genuine over time. Liu's own autobiographical account states that his initial opposition to Chiang Kai-shek and even his initial pro-communist tilt were purely out of pragmatic self-interest driven by a desire for political survival. According to Liu, he had become a committed communist over time after receiving political education from the Ya'an radio station during the Second Sino-Japanese War. Western journalist A.
Sources: en.wikipedia.org
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.
No. It has no approved medical indication in any country. Regulatory agencies have not cleared it for treatment or prevention of any condition.
Early clinical work stopped after rodent carcinogenicity findings. Those animal results raised concerns about long-term human risk, although direct human evidence is lacking. The human relevance of the tumors remains an open scientific question.
Cardarine is an investigational synthetic compound that acts as a PPARδ agonist. It is also known as GW501516 and has been studied mainly in preclinical research. It is not an approved medicine.