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Background And Regulatory History — What the Evidence Shows

By Editorial Desk · published 2026-07-12 · last reviewed 2026-07-27 · Info

Everything below concerns GW501516. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.

Updated 2026-07-27. Numbers and descriptions here follow the published literature rather than marketing material.

Background and Regulatory History

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 a common name for the investigational chemical GW501516, also written GW-1516. It was developed as a peroxisome proliferator-activated receptor delta agonist for metabolic conditions such as dyslipidemia. Early research focused on lipid handling and energy use in skeletal muscle and other tissues. The compound was never approved as a medicine. In public discussion, it is often grouped with performance-enhancing substances, although its receptor target differs from that of anabolic steroids or selective androgen receptor modulators. Regulatory and health authorities have issued warnings about its use.

Mechanism and Research Context

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.

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.

Cardarine at a glance

PropertyValueNotes
Common nameCardarineCommon internet and media name.
Research codeGW501516Also written GW-1516.
Drug classPPARδ agonistNot a selective androgen receptor modulator.
Development statusDiscontinuedClinical development halted after rodent cancer findings.
Regulatory statusProhibited in sportListed by WADA; not approved as medicine.

Background and Research Context

PPARδ is a nuclear receptor that regulates gene expression related to fatty acid oxidation, glucose homeostasis, and mitochondrial function. GW501516 binds to this receptor with high affinity and activates downstream signaling in skeletal muscle and other tissues. Animal studies reported increased endurance and altered fuel preference, but human data remain limited and inconsistent. The precise relationship between receptor activation and observed physiological changes is still an area of active investigation. Researchers have also examined whether the compound affects inflammation or cell proliferation. No approved therapeutic indication exists for cardarine.

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.

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Detection, Regulation, and Quality Context

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.

Regulatory treatment of cardarine differs by context and jurisdiction. In competitive sport, the World Anti-Doping Agency lists PPARδ agonists, including GW501516, as prohibited at all times. Outside sport, it lacks approval as a prescription medicine in major drug markets, and products sold for human consumption may be treated as unapproved drugs. Some countries also restrict importation or sale through general consumer protection and medicines laws. These classifications affect availability, testing, and legal risk without establishing therapeutic value.

Cardarine as Investigational PPARδ Agonist

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.

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.

Identity and Pharmacological Mechanism

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.

The compound is typically described as a laboratory compound rather than a therapeutic product. Published reports have explored its role in lipid disorders, insulin sensitivity, and exercise metabolism, yet no major drug regulator has approved it for medical use. Commercial samples sold under the cardarine name may vary in purity and identity. Analytical confirmation is therefore necessary when the material is discussed in scientific or regulatory contexts. Its classification as a prohibited substance in sport further shapes how it is studied and reported.

Notes from published material

The 3C-like protease (3CLpro) or main protease (Mpro), formally known as C30 endopeptidase, is the main protease found in coronaviruses. It cleaves the coronavirus polyprotein at eleven conserved sites. It is a cysteine protease and a member of the PA clan of proteases. It has a cysteine-histidine catalytic dyad at its active site and cleaves a Gln–(Ser/Ala/Gly) peptide bond. The Enzyme Commission refers to this family as SARS coronavirus main proteinase (Mpro; EC 3.4.22.69). The 3CL protease corresponds to coronavirus nonstructural protein 5 (nsp5). The "3C" in the common name refers to the 3C protease (3Cpro) which is a homologous protease found in picornaviruses.

Increased Factor IXa and Xa inhibition requires the minimal heparin pentasaccharide sequence. The conformational changes that occur within antithrombin in response to pentasaccharide binding are well documented. In the absence of heparin, amino acids P14 and P15 (see Figure 3) from the reactive site loop are embedded within the main body of the protein (specifically the top of beta sheet A). This feature is in common with other serpins such as heparin cofactor II, alpha 1-antichymotrypsin and MENT. The conformational change most relevant for Factor IXa and Xa inhibition involves the P14 and P15 amino acids within the N-terminal region of the reactive site loop (circled in Figure 4 model B). This region has been termed the hinge region. The conformational change within the hinge region in response to heparin binding results in the expulsion of P14 and P15 from the main body of the protein and it has been shown that by preventing this conformational change, increased Factor IXa and Xa inhibition does not occur. It is thought that the increased flexibility given to the reactive site loop as a result of the hinge region conformational change is a key factor in influencing increased Factor IXa and Xa inhibition. It has been calculated that in the absence of the pentasaccharide only one in every 400 antithrombin molecules (0.25%) is in an active conformation with the P14 and P15 amino acids expelled.

== History == The earliest description of a lectin is believed to have been given by Peter Hermann Stillmark in his doctoral thesis presented in 1888 to the Imperial University of Dorpat. Stillmark isolated ricin, an extremely toxic hemagglutinin, from seeds of the castor plant (Ricinus communis). Although lectins were first discovered in plants, they are now known to be present throughout nature. The first lectin to be purified on a large scale and available on a commercial basis was concanavalin A, which is now the most-used lectin for characterization and purification of sugar-containing molecules and cellular structures. The legume lectins are probably the most well-studied lectins. Long before a deeper understanding of their numerous biological functions was developed, the plant lectins, also known as phytohemagglutinins, were noted for their particularly high specificity for foreign glycoconjugates (e.g., those of fungi and animals) and used in biomedicine for blood cell testing and in biochemistry for fractionation.

He became a fellow of the American Physical Society in 1959, was elected to the National Academy of Sciences in 1979, and was named a Fellow of the American Academy of Arts and Sciences (AAAS) in 1983. Redfield received the Max Delbruck Prize from the American Physical Society in 2006. In 2007 he was recognized with the Russell Varian Prize for contributing the Redfield Relaxation Theory to the field of nuclear magnetic resonance. Redfield is descended from a family of pioneering scientists, including his father, Alfred C. Redfield, his second great-grandfather, William Charles Redfield, and his great-grandfather, the naturalist John Howard Redfield.

Ravneet Singh Bittu is an Indian politician from Punjab who served as the Minister of State for Railways and as the Minister of State for Food Processing Industries from 2024 till 2026 as a member of the Bharatiya Janata Party.

Sources: en.wikipedia.org

Further detail

Typically, healthy hearts have only two audible heart sounds, called S1 and S2. The first heart sound S1, is the sound created by the closing of the atrioventricular valves during ventricular contraction and is normally described as "lub". The second heart sound, S2, is the sound of the semilunar valves closing during ventricular diastole and is described as "dub". Each sound consists of two components, reflecting the slight difference in time as the two valves close. S2 may split into two distinct sounds, either as a result of inspiration or different valvular or cardiac problems. Additional heart sounds may also be present and these give rise to gallop rhythms. A third heart sound, S3 usually indicates an increase in ventricular blood volume. A fourth heart sound S4 is referred to as an atrial gallop and is produced by the sound of blood being forced into a stiff ventricle. The combined presence of S3 and S4 give a quadruple gallop. Heart murmurs are abnormal heart sounds which can be either related to disease or benign, and there are several kinds. There are normally two heart sounds, and abnormal heart sounds can either be extra sounds, or "murmurs" related to the flow of blood between the sounds.

=== Colubrids === Opisthoglyphous colubrids have enlarged, grooved teeth situated at the posterior extremity of the maxilla, where a small posterior portion of the upper labial or salivary gland produces venom.

==== pH regulation ==== Secretin primarily functions to neutralize the pH in the duodenum, allowing digestive enzymes from the pancreas (e.g., pancreatic amylase and pancreatic lipase) to function optimally. Secretin targets the pancreas; pancreatic centroacinar cells have secretin receptors in their plasma membrane. As secretin binds to these receptors, it stimulates adenylate cyclase activity and converts ATP to cyclic AMP. Cyclic AMP acts as second messenger in intracellular signal transduction and causes the organ to secrete a bicarbonate-rich fluid that flows into the intestine. Bicarbonate is a base that neutralizes the acid, thus establishing a pH favorable to the action of other digestive enzymes in the small intestine. Secretin also increases water and bicarbonate secretion from duodenal Brunner's glands to buffer the incoming protons of the acidic chyme, and also reduces acid secretion by parietal cells of the stomach. It does this through at least three mechanisms: 1) By stimulating release of somatostatin, 2) By inhibiting release of gastrin in the pyloric antrum, and 3) By direct downregulation of the parietal cell acid secretory mechanics. It counteracts blood glucose concentration spikes by triggering increased insulin release from pancreas, following oral glucose intake.

Thioquinapiperifil (also known as KF31327) is a synthetic drug which acts as a phosphodiesterase inhibitor, selective for the PDE5 subtype. It was synthesised as a potential treatment for disorders susceptible to treatment with PDE5 inhibitors such as erectile dysfunction, but was never developed for medical use. Subsequently it has been identified as an undisclosed ingredient in supposedly natural supplements for sexual enhancement, making it one of the few examples of a designer PDE5 inhibitor which is not a close analogue derived from either sildenafil, tadalafil or vardenafil.

Sources: en.wikipedia.org

Background from the literature

As Duke of Cumberland Ernest Augustus had been Grand Master of the Orange Order in England until it dissolved itself at the request of the King William IV following a government inquiry into public disorder in Ireland caused by Orange marches.

== Soundtrack == The film's soundtrack album was released by Deadmau5 on January 25, 2019, through his record label Mau5trap. The soundtrack's release details were announced on January 8, 2019, along with the film's initial trailer. A single from the soundtrack album, "Midas Heel" was released on January 11, 2019, followed by the vocal version called "Drama Free" featuring Lights which was previously released on Mau5ville: Level 2. Several tracks of the score (such as "Somb", "Wilhelm" and "End") feature elements from Deadmau5's previous tracks from his seventh studio album While(1<2), as well as two new tracks named "Nosedive" and "Camilla", the former being a remake of his unreleased track "Rio", the latter being known previously as "Suite 02". Elements of "Nosedive" would later be reused in his 2023 track "Input Output" as well.

==== Infections: HIV-AIDS, measles, RSV, others ==== The role of SP in HIV-AIDS has been well-documented. Doses of aprepitant greater than those tested to date are required for demonstration of full efficacy. Respiratory syncytial and related viruses appear to upregulate SP receptors, and rat studies suggest that NK1RAs may be useful in treating or limiting long term sequelae from such infections. Entamoeba histolytica is a unicellular parasitic protozoan that infects the lower gastrointestinal tract of humans. The symptoms of infection are diarrhea, constipation, and abdominal pain. This protozoan was found to secrete serotonin as well as Substance P and neurotensin.

Sources: en.wikipedia.org

Frequently asked questions

Is cardarine a selective androgen receptor modulator?

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.

Why did clinical development stop?

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.

Is cardarine approved for medical use?

No. It remains an investigational compound without approved therapeutic labeling. Sports regulators prohibit its use, and health agencies have warned against consuming it.

How does cardarine work in the body?

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.

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