A practical reference on Nuclear receptor: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
Reviewed 2025-08-20. Anything still debated is marked as such rather than presented as settled.
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.
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.
At the molecular level, GW501516 binds and activates PPARδ, a nuclear receptor that regulates transcription. Activation shifts expression of genes involved in fatty acid oxidation, energy expenditure, and lipid transport in skeletal muscle and liver. Animal studies report increased endurance and altered lipid profiles after exposure. Human data are limited to small trials and do not establish long-term safety or efficacy. PPARδ also has roles in cell proliferation, so the relationship between activation and cancer risk remains an open question.
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.
| Property | Value | Notes |
|---|---|---|
| Common synonyms | GW501516, GW-501516, GW 501516, endurobol | Names vary in research and anti-doping documents. |
| Chemical class | Synthetic PPARδ agonist | Small-molecule nuclear receptor ligand. |
| CAS Registry Number | 317318-70-0 | Identifier commonly associated with GW501516. |
| Appearance | White to off-white powder | Typical for purified research material. |
| Solubility | Low in water; soluble in DMSO and ethanol | Organic solvents are common for laboratory stock solutions. |
Legal status varies by country. In some places, cardarine is controlled under medicines or psychoactive substances laws; in others, it may be sold with minimal oversight as a research chemical. Customs agencies have intercepted shipments, and several national health agencies have issued warnings about products marketed for bodybuilding or performance enhancement. The lack of a standardized pharmaceutical supply means identity, purity, and contamination levels can differ widely between samples. These factors make cardarine a regulatory and public health concern rather than a conventional prescription drug.
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.
Because cardarine is not an approved medicine, no pharmacopeial monograph defines its identity, purity, or storage requirements. Laboratories typically rely on in-house methods and reference standards when testing materials labeled as GW501516. Certificates of analysis may report purity and identity for a specific batch, but their scope varies and they do not guarantee safety or legal status. Independent verification can include high-performance liquid chromatography, mass spectrometry, nuclear magnetic resonance, and elemental analysis. The distinction between research chemical labeling and human use is significant because quality standards and oversight differ.
Cardarine can be detected in biological samples and product materials using liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). The method separates compounds by chromatography and identifies them by mass-to-charge transitions, allowing low-level detection in urine or blood. Sample preparation often involves enzymatic hydrolysis, solid-phase extraction, or protein precipitation. Certified reference materials and isotope-labeled internal standards improve quantification. Detection windows depend on metabolism, matrix, and assay sensitivity, so no single universal window applies.
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.
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.
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.
=== Single unit transfusion === This refers to transfusing a single unit or bag of red blood cells to a person who is not bleeding and haemodynamically stable followed by an assessment to see if further transfusion is required. The benefits of single unit transfusion include reduced exposure to blood products. Each unit transfused increases the associated risks of transfusion such as infection, transfusion associated circulatory overload and other side effects. Transfusion of a single unit also encourages less wastage of red blood cells.
== History == 4-HO-MET was first synthesized and discovered by Alexander Shulgin in the 1970s. It was first described in the scientific literature by David Repke and colleagues by 1981. Subsequently, 4-HO-MET was described by Shulgin in his book TiHKAL (Tryptamines I Have Known and Loved) in 1997 as being- aside from its synthesis- indistinguishable from any other ethyl homologue. It was encountered as a novel recreational and designer drug in Europe by 2008 and recently in the United States in 2025.
A day later he confirmed that he would stand and was listed as a candidate, decrying Green Party leader Zack Polanski for former comments against Jeremy Corbyn and Polanski's stance on social issues. His decision to stand sparked a controversy within his party, with deputy leader Chris Williamson resigning and urging the party to support Polanski.
Several studies have found that Acraspeda is paraphyletic, with Hydrozoa being more closely related to Scyphozoa than to the other classes. At the same time, other studies have recovered Acraspeda as being monophyletic. The subphylum Anthozoa is argued to have either two or three classes, but the relationships between them is not disputed; the tube-dwelling anemones of the class Ceriantharia have consistently shown to be more closely related to the Hexacorallia than to the Octocorallia.
Sources: en.wikipedia.org
=== Vapor isotope effects === Vapor isotope effects occur for 1H, 2H, and 3H; since each isotope has different thermodynamic properties in the liquid and gas phases. For water, the condensed phase is more enriched while the vapor is more depleted. For example, rain condensing from a cloud, is heavier than the vapor starting point. Generally, the large variations in deuterium concentration in water are from fractionations between liquid, vapor, and solid reservoirs. In contrast to the fractionation pattern of water, non-polar molecules like oils and lipids, have gaseous counterparts enriched with deuterium relative to the liquid. This is thought to be associated with the polarity from hydrogen bonding in water that does not interfere in long-chain hydrocarbons.
Adolfo Suárez formed a government of young Francoist "reformists", in which he did not include any prominent figures ─ Fraga and Areilza, refused to participate ─ but which did not lack political experience. In his first statement, made before the TVE cameras, the new president presented his "reformist" project which contained important novelties of language and objectives and which caused a great impact on the majority of the population. He stated that his goal was to achieve "that the governments of the future be the result of the free will of the majority of Spaniards" and, after expressing his conviction that sovereignty resided in the people, he announced that they would express themselves freely in a general election to be called for before June 30 of the following year. It was a matter of "elevating to the category of normal what at street level is simply normal." Finally, Suárez announced that the "political reform" to be undertaken would be submitted to a referendum. The Political Reform Act bill, which was drafted jointly by the president of the Cortes, Torcuato Fernández Miranda, the vice-president of the government Alfonso Osorio and the Minister of Justice Landelino Lavilla, was very simple. A new Cortes was created, consisting of two chambers, the Congress of Deputies and the Senate, composed of 350 and 204 members respectively and elected by universal suffrage, except for the senators appointed by the king. And at the same time, all the institutions established in the fundamental laws other than the Cortes were implicitly abolished, i.e.
Pancreatic elastase;Feces-Pancreatic elastase;Clinical Biochemistry Laboratory; Adenovirus DNA PCR;Adenovirus DNA PCR - Feces; Clinical Microbiology Laboratory; "Hemoglobin;F";Feces-Blood; Clinical biochemistry laboratory; "Calprotectin;F";"Fecal Calprotectin;massfr."; Clinical biochemistry laboratory; Worms, eggs and cysts (microscopy of formalin-ether concentrate);Worms, eggs and cysts (microscopy of formalin-ether concentrate); Clinical Microbiology Laboratory; Larviculture (Strongyloides, hookworms);Larviculture (Strongyloides, hookworms); Clinical Microbiology Laboratory; Clostridioides difficile;Clostridioides difficile DNA/RNA (PCR quicktest); Clinical Microbiology Laboratory; Tarmpato e parasites;PCR (Tarmprotozoer); Clinical Microbiology Laboratory; Diarrhea investigation;Diarrhea investigation; Clinical Microbiology Laboratory; Alternative list Gastrointestinal stool and parasite tests The following analyses (Normal Order Name; Designation in the laboratory; Laboratory) can be performed on fecal samples.
Nucleosides are molecules formed by attaching a nucleobase to a ribose or deoxyribose ring. Examples of these include cytidine (C), uridine (U), adenosine (A), guanosine (G), and thymidine (T). Nucleosides can be phosphorylated by specific kinases in the cell, producing nucleotides. Both DNA and RNA are polymers, consisting of long, linear molecules assembled by polymerase enzymes from repeating structural units, or monomers, of mononucleotides. DNA uses the deoxynucleotides C, G, A, and T, while RNA uses the ribonucleotides (which have an extra hydroxyl(OH) group on the pentose ring) C, G, A, and U. Modified bases are fairly common (such as with methyl groups on the base ring), as found in ribosomal RNA or transfer RNAs or for discriminating the new from old strands of DNA after replication. Each nucleotide is made of an acyclic nitrogenous base, a pentose and one to three phosphate groups. They contain carbon, nitrogen, oxygen, hydrogen and phosphorus. They serve as sources of chemical energy (adenosine triphosphate and guanosine triphosphate), participate in cellular signaling (cyclic guanosine monophosphate and cyclic adenosine monophosphate), and are incorporated into important cofactors of enzymatic reactions (coenzyme A, flavin adenine dinucleotide, flavin mononucleotide, and nicotinamide adenine dinucleotide phosphate).
=== Presence in other species === Atherosclerosis primarily affects herbivorous species. Carnivorous animals such as dogs, cats, lions, and tigers can consume diets high in saturated fat and cholesterol without developing atherosclerotic plaques, as demonstrated in various studies. Atherosclerosis can be experimentally induced in carnivorous animals only by thyroidectomy. Removal of the thyroid gland appears to alter lipid metabolism, rendering saturated fat and cholesterol atherogenic in these species, similar to the effect observed in herbivores.
Sources: en.wikipedia.org
Coninae Fleming, 1822 — synonyms: Conulinae Rafinesque, 1815 (inv.); Textiliinae da Motta, 1995 (n.a.) Clathurellinae H. Adams & A. Adams, 1858 — synonyms: Defranciinae Gray, 1853 (inv.); Borsoniinae A. Bellardi, 1875; Pseudotominae A. Bellardi, 1888; Diptychomitrinae L. Bellardi, 1888; Mitrolumnidae Sacco, 1904; Mitromorphinae Casey, 1904; Lorinae Thiele, 1925 Conorbiinae de Gregorio, 1880—synonym: Cryptoconinae Cossmann, 1896 Mangeliinae P. Fischer, 1883—synonym: Cytharinae Thiele, 1929 Oenopotinae Bogdanov, 1987—synonym: Lorinae Thiele, 1925 sensu Thiele Raphitominae A. Bellardi, 1875—synonyms: Daphnellinae Casey, 1904; Taraninae Casey, 1904; Thatcheriidae Powell, 1942; Pleurotomellinae F. Nordsieck, 1968; Andoniinae Vera-Pelaez, 2002 † Siphopsinae Le Renard, 1995
On 4 June, Anvisa approved exceptional imports of Sputnik V, restricting it mainly to healthy adults and limiting it to only 1% of the population of 6 importing states, in order to manage risks through control and supervision of side effects. Anvisa said that the concern with replicating viruses has not been fully resolved, but that additional documents received indicate a substantially reduced acceptable amount. The new parameter would be in an FDA manual, which was not found. Anvisa also said that impurity and quality controls are insufficient and that the manufacturing plants must undergo corrections to meet WHO quality standards. As of 16 June, the same import conditions were extended to a total of 13 states. On 5 August, the consortium of northeastern Brazilian states, corresponding to 7 of the 13 states, suspended the import of 37 million doses due to the restrictions imposed by Anvisa. These doses will supply Mexico, Argentina and Bolivia.
=== Homology === In the genomic branch of bioinformatics, homology is used to predict the function of a gene: if the sequence of gene A, whose function is known, is homologous to the sequence of gene B, whose function is unknown, one could infer that B may share A's function. In structural bioinformatics, homology is used to determine which parts of a protein are important in structure formation and interaction with other proteins. Homology modeling is used to predict the structure of an unknown protein from existing homologous proteins. One example of this is hemoglobin in humans and the hemoglobin in legumes (leghemoglobin), which are distant relatives from the same protein superfamily. Both serve the same purpose of transporting oxygen in the organism. Although both of these proteins have very different amino acid sequences, their protein structures are very similar, reflecting their shared function and shared ancestor. Other techniques for predicting protein structure include protein threading and de novo (from scratch) physics-based modeling. Another aspect of structural bioinformatics include the use of protein structures for Virtual Screening models such as Quantitative Structure-Activity Relationship models and proteochemometric models (PCM). Furthermore, a protein's crystal structure can be used in simulation of for example ligand-binding studies and in silico mutagenesis studies.
== Semiconductor == The total current flow in the semiconductor consists of drift current and diffusion current of both the electrons in the conduction band and holes in the valence band. General form for electrons in one-dimension:
== External links == Insulin-Like+Growth+Factor+I at the U.S. National Library of Medicine Medical Subject Headings (MeSH) Overview of all the structural information available in the PDB for UniProt: P05019 (Insulin-like growth factor I) at the PDBe-KB.
Sources: en.wikipedia.org
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.
No. Cardarine is not a steroid hormone; it targets the nuclear receptor PPARδ. Its classification in anti-doping rules differs from anabolic steroids, though it remains prohibited in sport.
Early rodent studies reported tumor formation at multiple sites, which raised safety concerns. Sponsors stopped clinical development, and no approved human product exists.
Cardarine is a common name for the investigational compound GW501516. It acts as a PPARδ agonist and is not approved for human use. It is prohibited in sport.