If you have been reading about Nuclear receptor 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 2026-07-05. Where a claim depends on a specific study, the study is described rather than over-claimed.
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 prohibited in competitive sport under the World Anti-Doping Agency code, where it is classified as a metabolic modulator. It is not approved as a prescription medicine in the United States, European Union, or other major markets. Regulatory action has focused on its presence in sports and in products marketed as research chemicals. Because it has no accepted medical indication, supply is often unregulated. This status creates legal and safety uncertainties for anyone who encounters the substance.
Anti-doping laboratories detect GW501516 and its metabolites using liquid chromatography-tandem mass spectrometry. Urine is the most common matrix, though blood and dried blood spots may also be used in some programs. Detection depends on factors such as dose, timing, metabolism, and the sensitivity of the assay. Published methods describe limits of detection in the low nanogram per milliliter range for related compounds. Exact detection windows are not fixed for all situations and remain an area of ongoing study.
Products sold as cardarine have been found to contain incorrect compounds, variable amounts, or no active ingredient at all. Independent testing is required to verify identity and purity. Common analytical approaches include high-performance liquid chromatography, mass spectrometry, and nuclear magnetic resonance for structural confirmation. These methods can distinguish GW501516 from related PPAR agonists and from unrelated steroids. For regulators and researchers, such verification is central to interpreting both biological results and adverse event reports.
| Property | Value | Notes |
|---|---|---|
| Common name | Cardarine | Common internet and media name. |
| Research code | GW501516 | Also written GW-1516. |
| Drug class | PPARδ agonist | Not a selective androgen receptor modulator. |
| Development status | Discontinued | Clinical development halted after rodent cancer findings. |
| Regulatory status | Prohibited in sport | Listed by WADA; not approved as medicine. |
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.
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.
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.
C6H12O6 + 2 ADP + 2 Pi → 2 CH3CH(OH)COOH + 2 ATP + 2 H2O Anaerobic respiration is respiration in the absence of O2. Prokaryotes can utilize a variety of electron acceptors. These include nitrate, sulfate, and carbon dioxide. In anaerobic organisms and prokaryotes, different pathways result in ATP. ATP is produced in the chloroplasts of green plants in a process similar to oxidative phosphorylation, called photophosphorylation.
=== Persona non grata === The government of a country can declare a diplomat persona non grata, banning them from entering the country or expelling them if they have already entered. In non-diplomatic use, the authorities of a country may also declare a foreigner persona non grata permanently or temporarily, usually because of unlawful activity.
The two substrates of this enzyme are (S)-dihydroorotic acid and oxidised nicotinamide adenine dinucleotide phosphate (NADP+). Its products are orotic acid, reduced NADPH, and a proton. This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-CH group of donor with NAD+ or NADP+ as acceptor. The systematic name of this enzyme class is (S)-dihydroorotate:NADP+ oxidoreductase. Other names in common use include orotate reductase, dihydroorotate dehydrogenase, dihydro-orotic dehydrogenase, L-5,6-dihydro-orotate:NAD+ oxidoreductase, and orotate reductase (NADPH). It has one cofactor, FAD.
Sources: en.wikipedia.org
== Virginia House of Delegates == In 2005, Wittman was elected to the Virginia House of Delegates, representing the 99th district. He served on the Agricultural; Chesapeake and Natural Resources; and Police and Public Safety Committees.
=== Skin === Deficiencies in vitamin A have been linked to an increased susceptibility to skin infection and inflammation. Vitamin A appears to modulate the innate immune response and maintains homeostasis of epithelial tissues and mucosa through its metabolite, retinoic acid (RA). As part of the innate immune system, toll-like receptors in skin cells respond to pathogens and cell damage by inducing a pro-inflammatory immune response which includes increased RA production. The epithelium of the skin encounters bacteria, fungi and viruses. Keratinocytes of the epidermal layer of the skin produce and secrete antimicrobial peptides (AMPs). Production of AMPs resistin and cathelicidin, are promoted by RA.
=== Peptide nucleic acids (PNA) === Peptide nucleic acids are synthetic oligonucleotides that resist protease degradation and are used to induce repair at site-specific triplex formation regions on DNA genomic sites. PNAs are able to bind with high affinity and sequence specificity to a complementary DNA sequence through Watson-Crick base-pairing and are able to form triple helices through parallel orientation Hoogsteen bonds, with the PNA facing the 5'-end of the DNA strand. The PNA-DNA triplex is stable because PNAs consist of a neutrally charged pseudopeptide backbone which binds to the double stranded DNA (dsDNA) sequence. Similar to homopyrimidine in TFOs, homopyrimidine in PNAs is able to form a bond with the complementary homopurine in the target sequence of dsDNA. These DNA analogues are able to bind to dsDNA by exploiting ambient DNA conditions and different predicting modes of recognition. This is different from TFOs which bind though the major groove recognition of the dsDNA. One of the predicting modes of recognition used for recognition is through a duplex invasion. Within mixed A–T/G–C dsDNA sequence is targeted by a pair of pseudo-complementary (pc) PNAs which are able to bind to dsDNAs via double invasion through the simultaneous formation of diaminopurine (D) and thiouracil (Us) which substitute for adenine and thymine, respectively. The pc PNA pair form a D-T and Us -A and G-C or C-G Watson-Crick paired PNA-DNA helix with each of complementary DNA strands.
Sources: en.wikipedia.org
239Pu is a key fissile component in nuclear weapons, due to its ease of fission and availability. Encasing the bomb's plutonium pit in a tamper (a layer of dense material) decreases the critical mass by reflecting escaping neutrons back into the plutonium core. This reduces the critical mass from 16 kg to 10 kg, which is a sphere with a diameter of about 10 centimeters (4 in). This critical mass is about a third of that for uranium-235. The Fat Man plutonium bombs used explosive compression of plutonium to obtain significantly higher density than normal, combined with a central neutron source to begin the reaction and increase efficiency. Thus only 6 kg of plutonium was needed for an explosive yield equivalent to 20 kilotons of TNT. Hypothetically, as little as 4 kg of plutonium—and maybe even less—could be used to make a single atomic bomb using very sophisticated assembly designs.
Researchers learned to control the expression of transgenes, and were soon racing—in both academic and industrial contexts—to create organisms capable of expressing human genes for the production of human hormones. However, this was a more daunting task than molecular biologists had expected; developments between 1977 and 1980 showed that, due to the phenomena of split genes and splicing, higher organisms had a much more complex system of gene expression than the bacteria models of earlier studies. The first such race, for synthesizing human insulin, was won by Genentech. This marked the beginning of the biotech boom (and with it, the era of gene patents), with an unprecedented level of overlap between biology, industry, and law.
and Eyad A., accused of committing war crimes in Syria's government-run detention center, appeared in a German court for a first of its kind trial. According to a 2018 report released by the expert panel of United Nations, the Assad government-run detention centers tortured more than 4,000 of the detained protestors and murdered at least 58 others.
=== Surgery === A minimally invasive surgical therapy called serial ultrasound-guided aspiration can be performed to treat breast mastitis in an outpatient setting, achieving a better cosmetic postoperative recovery. On the other side, nipple pain caused by tongue-tie can seek a surgical therapy called frenotomy on infants. In this surgery, the frenulum under the tongue will be clipped to improve latch and remove the restriction of tongue movement. Hence, breastfeeding efficiency can be improved. However, it may not instantly relieve nipple pain since infants probably have developed uncommon tongue movements.
Sources: en.wikipedia.org
No. Cardarine is a PPARδ agonist, while selective androgen receptor modulators act on androgen receptors. The two classes differ in receptor target and downstream effects.
Preclinical rodent studies reported cancers, including liver and bladder tumors, at tested doses. The human relevance of those findings is uncertain, but development was discontinued. No approved human product resulted.
No. It remains an investigational compound without approved therapeutic labeling. Sports regulators prohibit its use, and health agencies have warned against consuming it.
Legal status varies by country, but cardarine is not approved as a medicine in major jurisdictions. It is often sold as a research chemical, a category that may not be lawful for human use. Buyers should check local laws and product labels carefully.