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Cardarine As Investigational Pparδ Agonist — Field Notes

By Editorial Desk · published 2026-01-28 · last reviewed 2026-03-21 · News

If you have been reading about anti-doping 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.

Updated 2026-03-21. Numbers and descriptions here follow the published literature rather than marketing material.

Cardarine as Investigational PPARδ Agonist

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.

Background and Regulatory Status

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.

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.

Cardarine at a glance

PropertyValueNotes
Common synonymsGW501516, GW-501516, GW 501516, endurobolNames vary in research and anti-doping documents.
Chemical classSynthetic PPARδ agonistSmall-molecule nuclear receptor ligand.
CAS Registry Number317318-70-0Identifier commonly associated with GW501516.
AppearanceWhite to off-white powderTypical for purified research material.
SolubilityLow in water; soluble in DMSO and ethanolOrganic solvents are common for laboratory stock solutions.

Regulation and Analytical Detection

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.

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.

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Background and Research Context

In laboratory settings, cardarine is studied as a tool compound for probing PPARδ biology. Published experiments often use cell cultures, rodent models, or isolated tissues. Some investigations focus on metabolic effects, while others assess potential risks such as carcinogenicity observed in long-term animal studies. Because human trials are sparse, most knowledge comes from preclinical work and adverse event reports. Scientific literature frequently notes the gap between animal findings and human outcomes. The compound is not a dietary supplement and is not intended for human consumption.

Cardarine is a common name for GW501516, a synthetic compound developed in the 1990s through research collaborations involving GlaxoSmithKline. It belongs to a class of molecules known as peroxisome proliferator-activated receptor delta agonists. Early studies explored its effects on lipid metabolism and energy expenditure in animal models. The compound was never approved as a human medicine, and clinical development was discontinued. In the years since, it has appeared in fitness and bodybuilding communities as a performance-enhancing substance. Regulatory agencies classify it as an unapproved drug.

Regulation and Detection

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.

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.

Mechanism and Detection Methods

Handling and quality assessment of cardarine reference material follow general laboratory practices for poorly characterized compounds. It typically appears as a white to off-white powder and is sparingly soluble in water but soluble in organic solvents such as dimethyl sulfoxide and ethanol. Storage recommendations usually specify a cool, dry, dark place, with long-term storage at low temperature and desiccation. Purity may be checked by high-performance liquid chromatography with ultraviolet detection, while identity is confirmed by mass spectrometry and nuclear magnetic resonance. No pharmacopeial monograph exists, so reported purity and stability depend on the supplier’s methods.

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.

Supporting material

== Definitions in science and industry == Temperature ranges are defined as room temperature for certain products and processes in industry, science, standards, and consumer goods. For instance, for the shipping and storage of pharmaceuticals, the United States Pharmacopeia-National Formulary (USP-NF) defines controlled room temperature as between 20 and 25 °C (68 and 77 °F), with excursions between 15 and 30 °C (59 and 86 °F) allowed, provided the mean kinetic temperature does not exceed 25 °C (77 °F). The European Pharmacopoeia defines it as being simply 15 to 25 °C (59 to 77 °F), and the Japanese Pharmacopeia defines "ordinary temperature" as 15 to 25 °C (59 to 77 °F), with room temperature being 1 to 30 °C (34 to 86 °F). Merriam-Webster gives as a medical definition a range of 15 to 25 °C (59 to 77 °F) as being suitable for human occupancy, and at which laboratory experiments are usually performed. In physics and chemistry, room temperature usually refers to the ambient temperature in the laboratory; for calculations one frequently assumes 20 °C, 25 °C or 300 K (26.85 °C).

== Process == Sake kasu is created during the sake brewing process. When koji, a type of fungus used for sake brewing, is added to steamed rice, it releases amylase enzyme. This enzyme breaks down the rice starch, creating sugar. After that, yeast is added to the mixture, transforming the sugar into alcohol. Finally, the fermented rice mash is compressed and the sake is drawn out of the mash. The residue that remains behind from the process is called sake kasu. Sake brewer Todd Bellomy estimates that in his brewery, 250 liters of sake kasu are produced as a by-product of every 700 liters that of sake that they produce. The weather conditions during rice growing can affect the production of sake kasu. In high temperatures, the starch inside the rice grain has a less soluble structure. This boosts the amount of sake kasu and reduces the taste of Japanese sake due to the reduction of the solubility of the rice. In contrast, when the weather is cooler, the rice grains are finer, and the solubility is higher. Thus, creating less sake kasu and the taste of Japanese sake will be stronger.

=== Time and frequency === Government standard frequency and time signal services operate time radio stations which continuously broadcast extremely accurate time signals produced by atomic clocks, as a reference to synchronize other clocks. Examples are BPC, DCF77, JJY, MSF, RTZ, TDF, WWV, and YVTO. One use is in radio clocks and watches, which include an automated receiver that periodically (usually weekly) receives and decodes the time signal and resets the watch's internal quartz clock to the correct time, thus allowing a small watch or desk clock to have the same accuracy as an atomic clock. Government time stations are declining in number because GPS satellites and the Internet Network Time Protocol (NTP) provide equally accurate time standards.

protein kinase Any of a class of enzymes which phosphorylate proteins by catalyzing the transfer of a phosphate from ATP to an amino acid residue and often causing a functionally relevant conformational change as a result. The great majority of protein kinases phosphorylate the hydroxyl side chains of either serine, threonine, or tyrosine, though other types also exist. Separate classes of kinases phosphorylate non-protein molecules such as lipids and carbohydrates.

Sources: en.wikipedia.org

Supporting material

are the rates of the forward and backward reaction, respectively in the conversion of individual E and S to the enzyme substrate complex. Information theory allows for a more quantitative definition of specificity by calculating the entropy in the binding spectrum.

== Response mechanism == It is not immediately obvious why the capture of electrons by electronegative analytes reduces the current that flows between the anode and cathode: the molecular negative ions of the analyte carry the same charge as the electrons that were captured. The key to understanding why the current decreases is to ask where charged entities can go besides being collected at the anode and cathode. The answer is recombination of negative ions or electrons with the positive ions of the makeup gas before these charged entities can be collected at anode and cathode respectively. Negative and positive ions recombine much more rapidly than electrons and positive ions; it is this more rapid neutralization that is the origin of the observed decrease in current. Examination of the rate balance equation with all charge production and loss mechanisms considered reveals that the current collected when the electron capture detector is saturated with analyte is not zero: it is half the current collected when no analyte is present. To laboratory chromatographers this theoretical result is a well known experimental observation.

The majority of mummies recovered in the Czech Republic come from underground crypts. While there is some evidence of deliberate mummification, most sources state that desiccation occurred naturally due to unique conditions within the crypts. The Capuchin Crypt in Brno contains three hundred years of mummified remains directly below the main altar. Beginning in the 18th century when the crypt was opened, and continuing until the practice was discontinued in 1787, the Capuchin friars of the monastery would lay the deceased on a pillow of bricks on the ground. The unique air quality and topsoil within the crypt naturally preserved the bodies over time. Approximately fifty mummies were discovered in an abandoned crypt beneath the Church of St. Procopius of Sázava in Vamberk in the mid-1980s. Workers digging a trench accidentally broke into the crypt, which began to fill with waste water. The mummies quickly began to deteriorate, though thirty-four were able to be rescued and stored temporarily at the District Museum of the Orlické Mountains until they could be returned to the monastery in 2000. The mummies range in age and social status at time of death, with at least two children and one priest. The majority of the Vamberk mummies date from the 18th century. The Klatovy catacombs currently house an exhibition of Jesuit mummies, alongside some aristocrats, that were originally interred between 1674 and 1783. In the early 1930s, the mummies were accidentally damaged during repairs, resulting in the loss of 140 bodies.

=== Cattle === In dairy cattle, ketosis commonly occurs during the first weeks after giving birth to a calf and is sometimes referred to as acetonemia. This is most likely the result of an energy deficit when intake is inadequate to compensate for the increased metabolic demand of lactating. The elevated β-hydroxybutyrate concentrations can depress gluconeogenesis, feed intake and the immune system, as well as have an impact on milk composition. Point of care diagnostic tests can be useful to screen for ketosis in cattle.

I have not found a "smoking gun" which shows that Mr Galloway has, personally and directly, unlawfully received moneys from the former Iraqi regime. However I have amassed a very substantial body of evidence from a variety of sources which is generally internally consistent and, in my view: a) Clearly shows that Mr Galloway's anti-sanctions work through the Mariam Appeal was in effect supported by the former Iraqi regime, through Mr Fawaz Zureikat and using, among other things, the mechanism of the Oil for Food Programme. b) Clearly shows that Mr Galloway at best turned a blind eye to the fact that this was happening.

Sources: en.wikipedia.org

Frequently asked questions

What is cardarine?

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.

Is cardarine a steroid?

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.

Why was cardarine not developed further?

Early rodent studies reported tumor formation at multiple sites, which raised safety concerns. Sponsors stopped clinical development, and no approved human product exists.

Is cardarine approved for human use?

No. Major drug regulators have not approved GW501516 for treating any medical condition. Products sold as cardarine are typically unapproved research chemicals or supplements, so their contents and safety are not assured.

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