anti-doping is one of those subjects where the details matter more than the headlines. This page pulls together the background, the mechanisms, and the practical points readers ask about most.
Updated 2025-09-21. Numbers and descriptions here follow the published literature rather than marketing material.
GW501516 acts as a selective agonist at PPARδ, a nuclear receptor that regulates transcription of genes involved in lipid handling and energy metabolism. Activation of PPARδ in preclinical models increases fatty acid oxidation, mitochondrial biogenesis, and exercise endurance in rodents. These effects have made the compound a subject of metabolic research and also a target for sport anti-doping rules. In humans, however, controlled studies are limited, and whether similar endurance or metabolic changes occur at tolerated exposures remains an open question. The receptor’s broad tissue distribution also means downstream effects may vary by organ and condition.
Detection of GW501516 in biological samples generally relies on liquid chromatography coupled with tandem mass spectrometry. Urine is a common matrix in anti-doping analysis, while blood or plasma may be used in research settings. Sample preparation can involve enzymatic hydrolysis, protein precipitation, or solid-phase extraction before instrumental analysis. Because the compound undergoes metabolism, assays may target the parent molecule, one or more metabolites, or both. Detection windows are not fixed; they depend on factors such as dose, route, individual metabolism, and assay sensitivity. Reference standards are required for accurate identification and quantification.
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.
| Property | Value | Notes |
|---|---|---|
| Appearance | White to off-white powder | Visual description for typical solid reference material. |
| Solubility | Poorly soluble in water; soluble in DMSO | Solubility depends on solvent, purity, and form. |
| Storage | Cool, dry, protected from light | Long-term storage often uses low temperature and desiccant. |
| Common analytical method | LC-MS/MS | Used for detection and quantification in biological matrices. |
| Common synonyms | GW-501516; GW501516; endurobol | Naming varies among literature, vendors, and databases. |
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.
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.
== Cultivation == The climbing varieties are valued for their ability to scramble up walls, fences, and other structures, and also to grow through other plants, such as shrubs and trees. Some can be trained along the ground to provide cover. Because of their adaptability and masses of spectacular flowers, clematis are among the most popular of all garden plants. Many choice and rare cultivars are to be had from mail order and online catalogues. Specialists regularly put on displays in national flower shows such as the Chelsea Flower Show. In theory, it is possible to have a clematis in flower at any time throughout the year. Many varieties provide a second period of interest with a flush of flowers, or decorative seed heads. They will grow in any good garden soil. The roots usually require a moist, cool substrate, while the herbage can take full sun. Some more delicate cultivars such as 'Nelly Moser' do better in light shade. Many clematis can be grown successfully in containers.
This means that, on average, its papers published in 2015 and 2016 received roughly 42 citations each in 2017. Impact factors are reported in the subsequent year, when all of the previous year's publications have been processed by the indexing agency. The value of impact factor depends on how to define "citations" and "publications"; the latter are often referred to as "citable items". In current practice, both "citations" and "publications" are defined exclusively by ISI as follows: "Publications" are items that are classed as "article", "review" or "proceedings paper" in the Web of Science (WoS) database; other items like editorials, corrections, notes, retractions and discussions are excluded. WoS is accessible to all registered users, who can independently verify the number of citable items for a given journal. In contrast, the number of citations is extracted not from the WoS database, but from a dedicated JCR database, which is not accessible to general readers. Hence, the commonly used "JCR Impact Factor" is a proprietary value, which is defined and calculated by ISI and can not be verified by external users. New journals, which are indexed from their first published issue, will receive an impact factor after two years of indexing; in this case, the citations to the year prior to volume 1, and the number of articles published in the year prior to volume 1, are known zero values. Journals that are indexed starting with a volume other than the first volume will not get an impact factor until they have been indexed for three years.
== Lifespan == Gastric pit cells are replaced every 2–4 days. This high rate of turnover is a protective mechanism designed to protect the epithelial lining of the stomach from both the proteolytic action of pepsin and the acid produced by parietal cells. Gastric chief cells are much longer lived and are believed to differentiate from stem cells located higher in the gastric unit in the isthmus. These stem cells differentiate into mucous neck cells in the isthmus and transition into chief cells as they migrate towards the base. Since the mucus neck cells do not divide as it becomes a chief cell this process is known as transdifferentiation. The gene Mist1 has been shown to regulate mucus neck cell to chief cell transdifferentiation and plays a role in the normal development of the chief cell organelles and structures.
Sources: en.wikipedia.org
=== Active regions === A model based on electron crystallographic density and nuclear magnetic resonance deconvolution has been proposed to explain the binding of docetaxel to β-tubulin. In this T-shaped/butterfly model, a deep hydrophobic cleft exists near the surface of the β-tubulin where three potential hydrogen bonds and multiple hydrophobic contacts bind to docetaxel. The hydrophobic pocket walls contain helices H1, H6, H7 and a loop between H6 and H7 that form hydrophobic interactions with the 3'-benzamido phenyl, 3'-phenyl, and the 2-benzoyl phenyl of docetaxel. 3'-phenyl also has contact with β-sheets B8 and B10. The C-8 methyl of docetaxel has Van der Waals interactions with two residues, Thr-276 and Gln-281 near the C-terminal end of β-tubulin. Docetaxel's O-21 experiences electrostatic attraction to Thr-276 and the C-12 methyl has proximity with Leu-371 on the loop between B9 and B10.
William Henry Vanderbilt* (1841), eldest son of Cornelius Vanderbilt; president of the New York Central Railroad, Lake Shore and Michigan Southern Railway, Canada Southern Railway, and Michigan Central Railroad Robert Morrison Olyphant (1842), heir to trading company Olyphant & Co. and president of the Delaware and Hudson Railway Charles Carow* (1844), businessman son of shipping magnate Isaac Carow, father of first lady Edith Carow Roosevelt Frederic W. Rhinelander (1847), 3rd president of the Metropolitan Museum of Art William Backhouse Astor Jr. (1849), son of William Backhouse Astor Sr. and husband of Caroline Webster Schermerhorn Astor, co-founder of The Four Hundred list of socialites and Florida Yacht Club Robert L. Cutting Jr. (1856), banker and clubman, son of Robert L. Cutting '30 George Lovett Kingsland (1856), merchant and railroad executive, son of New York City mayor Ambrose Kingsland Goold H. Redmond (1857), banker and sportsman Charles Henry Marshall (1858), businessman, former commissioner of Docks and Ferries of the City of New York, grandfather of publisher Marshall Field IV John Crosby Brown (1859), heir to investment bank Brown Bros. & Co., which later became Brown Brothers Harriman & Co., the oldest private bank in the U.S. Emory McClintock (1859), actuary; president of the American Mathematical Society and the Actuarial Society of America Robert Goelet (1860), real estate developer Rutherfurd Stuyvesant (1863), socialite, heir to the Stuyvesant family fortune J.
== Further reading == Bachner, Paul (2021). In further pursuit of excellence: the college of American pathologists 1946-2020 (PDF) (1st ed.). Northfield: College of American Pathologists. ISBN 978-1-941096-61-1.
Sources: en.wikipedia.org
Cardarine targets PPARδ, a nuclear receptor involved in lipid and energy metabolism. It does not bind the androgen receptor in the way SARMs do.
Most methods use liquid chromatography with tandem mass spectrometry. Urine is common in anti-doping testing, and blood or plasma may be used in research.
Typical guidance is cool, dry, dark storage, often at low temperature and with desiccant. Stability data are limited, so storage conditions should be verified for each batch or supplier.
Cardarine is commonly known as GW501516 or GW-1516. These names refer to the same synthetic compound. It is not a brand-name approved medicine.