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 2025-10-18. Where a claim depends on a specific study, the study is described rather than over-claimed.
GW501516 acts as an agonist at peroxisome proliferator-activated receptor delta, a nuclear receptor involved in transcription of genes related to lipid handling and energy use. Activation of PPARδ can shift skeletal muscle toward greater fatty acid oxidation in animal models, which is one reason it drew interest for metabolic disease and exercise research. The exact downstream effects depend on tissue, species, dose, and duration. Human data are sparse, so many proposed benefits remain hypotheses rather than established clinical outcomes.
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.
Cardarine is a common name for GW501516, a synthetic compound studied for its effects on lipid and glucose metabolism. It functions as an agonist at peroxisome proliferator-activated receptor delta, or PPARδ, a nuclear receptor that influences gene expression. The molecule is not a steroid, nor is it a selective androgen receptor modulator. It is also known in research and sports literature as GW-501516 and endurobol. Early laboratory work examined its metabolic activity in cell cultures and animal models.
Activation of PPARδ changes transcription of genes involved in fatty acid transport, mitochondrial function, and skeletal muscle fuel preference. In rodent studies, pharmacological PPARδ activation was associated with increased endurance and altered body composition. These findings generated interest in performance enhancement, but species differences and study designs limit direct extrapolation to humans. Small human trials were conducted in the 2000s and later discontinued. The extent to which cardarine produces similar metabolic or performance effects in people remains an open question.
| Property | Value | Notes |
|---|---|---|
| Solubility | Soluble in dimethyl sulfoxide and some organic solvents; practically insoluble in water | Solvent choice affects laboratory handling |
| Typical storage | -20 °C, desiccated, protected from light | Common condition for research samples |
| Analytical method | Liquid chromatography–tandem mass spectrometry (LC-MS/MS) | Used for identification and quantification in biological or product samples |
| Common synonyms | GW501516, GW-501516, GSK-516, Endurobol | Names found in research and anti-doping literature |
| Regulatory status | Unapproved therapeutic; prohibited in competitive sport | Status can vary by country and context |
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.
A common misconception is that cardarine has been proven safe for human use. In reality, human clinical data are limited, and long-term animal studies have raised concerns about cancer. Another misconception is that it is a supplement or vitamin-like compound. It is a synthetic research chemical with no approved medical indication. Scientific discussion often focuses on its mechanism and detection rather than therapeutic use. Regulatory and anti-doping literature treats it primarily as a prohibited substance.
Cardarine is explicitly prohibited by the World Anti-Doping Agency under the class of PPARδ agonists. Its presence in urine or blood samples can be detected using mass spectrometry-based methods, often liquid chromatography-tandem mass spectrometry. Athletes who test positive may face sanctions, including bans from competition. The compound is also regulated as a prescription-only or unapproved drug in many countries. Enforcement varies by jurisdiction, and some regions treat it as a controlled substance. Online sales may occur despite these restrictions, creating quality and legal risks.
Laboratory detection of cardarine typically involves sample preparation followed by chromatographic separation and mass spectrometric identification. Urine is the most common matrix for anti-doping tests, though blood and hair have also been explored. Methods can target the parent compound or its metabolites, depending on the expected window of detection. Reference standards are required for accurate quantification. Matrix effects and dilution can influence results, so laboratories use internal standards and validation protocols. The exact detection window varies with dose, route, and individual metabolism.
Published literature on cardarine includes in vitro assays, rodent experiments, and a small number of human studies. Reports describe effects on exercise capacity and lipid metabolism in animals, while human evidence is sparse. Many online descriptions present the compound as a proven endurance aid, a claim not supported by regulatory approval or large clinical trials. Analytical studies focus on identifying the parent compound and its metabolites in biological samples. Important uncertainties include species differences, dose-response relationships, and the relevance of rodent tumor findings to humans.
Cardarine is the common name for GW501516, a synthetic compound studied as a peroxisome proliferator-activated receptor delta agonist. Researchers developed it to explore treatments for lipid disorders and metabolic conditions. It is not an approved medicine in any country. Early clinical work examined changes in HDL cholesterol and triglycerides, but development was discontinued after animal studies raised concerns about cancer. The compound remains available as a research chemical and appears in discussions of performance enhancement.
== Indications == DBNPA is used as a disinfectant, bactericide, algicide, slime remover, and mildew inhibitor in several industrial applications. It is frequently used to regulate the growth of bacteria, algae, and slime in oilfield water injection systems and circulating cooling water systems. DBNPA is used in the paper industry as a slime remover, bactericide, and algicide to keep machinery free of microorganisms and maintain product quality. Additionally, it is utilized as a preservative to prevent microbiological deterioration in paints, waxes, inks, detergents, surfactants, slurries, and resins. DBNPA also serves as a fungicide and algaecide in municipal water landscapes, guaranteeing water safety and clarity, and as a biocide in process water and air purifier systems in the machinery manufacturing sector. The concentration used when it is being used as a water treatment slime stripper is 30~50 mg/L. When it is being used for water treatment, as a bactericide, it is used at a concentration of 10~20 mg/L. In terms of analytical detection in industrial and environmental samples, high-performance liquid chromatography with UV detection, measuring absorption at 230 nm, detects DBNPA at extremely low concentrations (>0.1 mg/L) in water samples. Gas chromatography-mass spectrometry can also identify and quantify DBNPA and the associated degradation products, (detection limit is 0.05 mg/L) in environmental samples.
Edward Said asked many times, in public and private, where the Mandela of Palestine could be. In rather bold contrast to this decent imagination, Arafat managed to be both a killer and a compromiser (Mandela was neither), both a Swiss bank account artist and a populist ranter (Mandela was neither), both an Islamic "martyrdom" blow-hard and a servile opportunist, and a man who managed to establish a dictatorship over his own people before they even had a state (here one simply refuses to mention Mandela in the same breath). Hitchens had previously collaborated on this issue with Edward Said, publishing the 1988 book Blaming the Victims: Spurious Scholarship and the Palestinian Question. Hitchens had said of himself, "I am an Anti-Zionist. I'm one of those people of Jewish descent who believes that Zionism would be a mistake even if there were no Palestinians." and "If Jews born in Brooklyn have a right to a state in Palestine, then Palestinians born in Jerusalem have a right to a state in Palestine. Anyone who doesn't agree with that principle I think is suspect." A review of his autobiography Hitch-22 in The Jewish Daily Forward refers to Hitchens "at the time [that he had learned that his grandparents were Jews, he had been] a prominent anti-Zionist" and says that he viewed Zionism "as an injustice against the Palestinians". Others have commented on his anti-Zionism as well.
The dependence of medical care on the meat industry assumed threatening proportions in the wake of the COVID-19 pandemic. In 2020, several studies demonstrated the efficacy of heparin in mitigating severe disease progression, as its anticoagulant effect counteracted the formation of immunothrombosis. However, the availability of heparin on the world market was decreased, because concurrently a renewed swine flu epidemic had reduced significant portions of the Chinese hog population. The situation was further exacerbated by the fact that mass slaughterhouses around the world became coronavirus hotspots themselves and were forced to close temporarily. In less affluent countries, the resulting heparin shortage also led to worsened health care beyond the treatment of COVID-19, for example through the cancellation of cardiac surgeries.
Sources: en.wikipedia.org
== Analogues in non-vertebrate organisms == A variety of oxygen-transport and -binding proteins exist in organisms throughout the animal and plant kingdoms. Organisms including bacteria, protozoans, and fungi all have hemoglobin-like proteins whose known and predicted roles include the reversible binding of gaseous ligands. Since many of these proteins contain globins and the heme moiety (iron in a flat porphyrin support), they are often called hemoglobins, even if their overall tertiary structure is very different from that of vertebrate hemoglobin. In particular, the distinction of "myoglobin" and hemoglobin in lower animals is often impossible, because some of these organisms do not contain muscles. Or, they may have a recognizable separate circulatory system but not one that deals with oxygen transport (for example, many insects and other arthropods). In all these groups, heme/globin-containing molecules (even monomeric globin ones) that deal with gas-binding are referred to as oxyhemoglobins. In addition to dealing with transport and sensing of oxygen, they may also deal with NO, CO2, sulfide compounds, and even O2 scavenging in environments that must be anaerobic. They may even deal with detoxification of chlorinated materials in a way analogous to heme-containing P450 enzymes and peroxidases.
==== Japan ==== Taco Bell once operated shops in Tokyo and Nagoya in the 1980s but withdrew several years later. Since then, there were shops only at United States Forces Japan bases. In 2015, Taco Bell returned to the Japanese market with a new shop in the downtown area of Shibuya, Tokyo. It had "Taco rice" and "Shrimp and avocado burrito" on its original menu.
Cyclic glycine-proline (cGP) is a small neuroactive peptide that belongs to a group of bioactive 2,5-diketopiperazines (2,5-DKPs) and is also known as cyclo-glycine-proline. cGP is a neutral, stable naturally occurring compound and is endogenous to the human body; found in human plasma, breast milk and cerebrospinal fluid. DKPs are bioactive compounds often found in foods. Cyclic dipeptides such as 2,5 DKPs are formed by the cyclisation of two amino acids of linear peptides produced in heated or fermented foods. The bioactivity of cGP is a property of functional foods and presents in several matrices of foods including blackcurrants. cGP is metabolite of hormone insulin-like growth factor-1 (IGF-1). It has a cyclic structure, lipophilic nature, and is enzymatically stable which makes it a more favorable candidate for manipulating the binding-release process between IGF-1 and its binding protein thereby, normalizing IGF-1 function. Under the trade name Traneurocin (developmental code name NA-831), it is being developed as a racetam-like drug for the treatment of COVID-19, Alzheimer's disease, fragile X syndrome, Rett syndrome, major depressive disorder, and other neurological disorders. In the case of COVID-19, it is specifically being developed for treatment of COVID-19-induced neuropathy.
=== Animal health === One meta-analysis published in 2003 suggested a negative impact of rBST's effects on bovine health. Findings suggested an average increase in milk output ranging from 11–16%, an approximate 24% increase in the risk of clinical mastitis, a 40% reduction in fertility, and 55% increased risk of developing clinical signs of lameness. The same study reported a decrease in body condition score for cows treated with rBST, though an increase in their dry matter intake occurred. Another meta-analysis (2003) reported on body condition scores (BCS) but could not reach a conclusion due to lack of homogeneity in study design and reporting. They found a trend towards decreased BCS in treated cows but state "Depending on the level of body condition in these cows, this effect may have been beneficial or detrimental." This analysis did not report on clinical mastitis. A more recent meta-analysis (2014) published by the Journal of the American Veterinary Medical Association showed no significant increase in risk of clinical mastitis nor other adverse effects on cow health and well-being. This review included 26 peer-reviewed studies that involved the use of the rBST-Zn formulation available to US producers in accordance with the label instructions for treatment initiation (57 to 70 days after birth), dose (500 mg, every 14 days), and route (subcutaneous). Mastitis has cost American dairy industries an estimated $1.5 to 2 billion per year in treating dairy cows.
Sources: en.wikipedia.org
There is a trend towards prohibition of beak trimming in Europe over the course of decades. Analysts expect the practice to be gradually banned across the continent. EU law allows member states to debeak poultry according to two regulations: Directive 1999/74/EC for laying hens allows beak trimming, while Directive 2007/43/EC for broilers permits beak trimming only in certain cases. As of April 2019, 80% of laying hens in the EU were estimated to be beak-trimmed.
== External links == "Opioid Receptors: δ". IUPHAR Database of Receptors and Ion Channels. International Union of Basic and Clinical Pharmacology. Archived from the original on 2014-02-23. Retrieved 2007-07-23. delta+Opioid+Receptor at the U.S. National Library of Medicine Medical Subject Headings (MeSH)
=== Cigars === Like other forms of smoking, cigar smoking poses a significant health risk depending on dosage: risks are greater for those who inhale more when they smoke, smoke more cigars, or smoke them longer. The risk of dying from any cause is significantly greater for cigar smokers, with the risk particularly higher for smokers less than 65 years old, and with risk for moderate and deep inhalers reaching levels similar to cigarette smokers. The increased risk for those smoking 1–2 cigars per day is too small to be statistically significant, and the health risks of the 3/4 of cigar smokers who smoke less than daily are not known and are hard to measure. Although it has been claimed that people who smoke fewer than five cigars a day have no increased risks, a more accurate statement is that their risks are proportionate to their exposure. Health risks are similar to cigarette smoking in nicotine addiction, periodontal health, tooth loss, and many types of cancer, including cancers of the mouth, throat, and esophagus. Cigar smoking can also cause cancers of the lung, and larynx, where the increased risk is less than that of cigarettes. Many of these cancers have extremely low cure rates. Cigar smoking also increases the risk of lung and heart diseases such as chronic obstructive pulmonary disease (COPD).
Amines, alkyl and aryl alike, are organized into three subcategories (see table) based on the number of carbon atoms adjacent to the nitrogen (how many hydrogen atoms of the ammonia molecule are replaced by hydrocarbon groups): Primary (1°) amines—Primary amines arise when one of three hydrogen atoms in ammonia is replaced by an alkyl or aromatic group. Important primary alkyl amines include methylamine, most amino acids, and the buffering agent tris, while primary aromatic amines include aniline. Secondary (2°) amines—Secondary amines have two organic substituents (alkyl, aryl or both) bound to the nitrogen together with one hydrogen. Important representatives include dimethylamine, while an example of an aromatic amine would be diphenylamine. Tertiary (3°) amines—In tertiary amines, nitrogen has three organic substituents. Examples include trimethylamine, which has a distinctively fishy smell, and EDTA. A fourth subcategory is determined by the connectivity of the substituents attached to the nitrogen:
== Method translation == Faster GC methods have shorter times but Kovats indices of the compounds may be conserved if proper method translation is applied. Temperatures of the temperature program stay the same, but ramps and times change when using a smaller column or faster carrier gas. If column dimensions Length×diameter×film are divided by 2 and gas velocity is doubled by using H2 in place of Helium, the hold times must be divided by 4 and the ramps must be multiplied by 4 to keep the same index and the same retention temperature for the same compound analyzed. Method translation rules are incorporated in some chromatography data systems.
Sources: en.wikipedia.org
It binds and activates PPARδ, a nuclear receptor that influences gene expression related to fatty acid metabolism and energy balance. This mechanism has been studied mainly in animals and cell models, not established as a safe human therapy.
No. It is not an anabolic-androgenic steroid; it is a synthetic PPARδ agonist. Because it is banned in sport, it is sometimes grouped with doping agents even though its chemical class differs from steroids.
Human data are limited and development was discontinued, so major effects and long-term risks are not well characterized. Some early studies examined metabolic markers, but they do not provide a basis for unsupervised use.
Cardarine is a common name for GW501516, a synthetic PPARδ agonist. It is not a steroid or a selective androgen receptor modulator. It was developed and studied as a research compound for metabolic pathways.