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Cardarine As Investigational Pparδ Agonist — Common Mistakes

By Editorial Desk · published 2026-03-26 · last reviewed 2026-05-15 · Wiki

If you have been reading about Prohibited substance 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 2026-05-15. Where a claim depends on a specific study, the study is described rather than over-claimed.

Cardarine as Investigational PPARδ Agonist

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.

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.

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.

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.

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Mechanism and Laboratory Detection

GW501516 binds and activates PPARδ, a nuclear receptor that influences transcription of genes involved in fatty acid oxidation and energy use. Activation shifts some metabolic pathways in preclinical models, which is why the compound has been studied for lipid disorders and exercise-related endpoints. The exact downstream effects in humans are incompletely mapped. PPARδ is expressed in many tissues, including skeletal muscle, liver, and adipose tissue, so broad activation may have varied consequences. Researchers continue to examine how selective or partial activation might alter the balance between benefits and risks.

Published human data are sparse and mostly come from early-phase trials. Those studies examined short-term changes in lipids, glucose, and exercise capacity, but they were not large enough to establish efficacy or long-term safety. Some animal experiments reported increased running endurance, yet such findings do not prove a performance benefit in people. Anti-doping laboratories detect GW501516 and its metabolites in urine or blood using liquid chromatography-tandem mass spectrometry. Detection windows depend on dose, sample type, and individual metabolism. The method is sensitive enough to identify trace residues in tested samples.

Regulation and Analytical Detection

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.

Mechanism and Detection 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.

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.

Further detail

This enzyme is the extracellular nuclease of Staphylococcus aureus. Two strains, V8 and Foggi, yield almost identical enzymes. A common source is E.coli cells carrying a cloned nuc gene encoding Staphylococcus aureus extracellular nuclease (micrococcal nuclease). The 3-dimensional structure of micrococcal nuclease (then called Staphyloccal nuclease) was solved very early in the history of protein crystallography, in 1969. Higher-resolution, more recent crystal structures are available for the apo form and for the thymidine-diphosphate-inhibited form. As seen in the ribbon diagram above, the nuclease molecule has 3 long alpha helices and a 5-stranded, barrel-shaped beta sheet, in an arrangement known as the OB-fold (for oligonucleotide-binding fold) as classified in the SCOP database.

In November 2016, India's Drug Consultative Committee announced it was embarking on establishing a definition of drugs which could be dispensed without a prescription. Prior to this, the general assumption was that any drug which did not fall into a prescription schedule could be purchased without a prescription. However, the needed definition had not been enacted by early 2018. The lack of a legal definition for OTC drugs has led to this US$4 billion market segment being effectively unregulated. In the Netherlands, there are four categories:

Recycling chromatography is mode practiced in both HPLC and CCC. In recycling chromatography, the target compounds are reintroduced into the column after they elute. Each pass through the column increases the number of theoretical plates the compounds experience and enhances chromatographic resolution. Direct recycling must be done with an isocratic solvent system. With this mode, the eluant can be selectively re-chromatographed on the same or a different column in order to facilitate the separation. This process of selective recycling has been termed a "heart-cut" and is especially effective in purifying selected target compounds with some sacrificial loss of recovery. The process of re-separating selected fractions from one chromatography experiment with another chromatographic method has long been practiced by scientists. Recycling and sequential chromatography is a streamlined version of this process. In CCC, the separation characteristics of the column may be modified simply by changing the composition of the biphasic solvent system.

Dysphoria and apathy (due to dopamine receptor blockade) Sedation (particularly common with asenapine, clozapine, olanzapine, quetiapine, chlorpromazine and zotepine) Headaches Dizziness Diarrhea Anxiety Extrapyramidal side effects (particularly common with first-generation antipsychotics), which include: Akathisia, an often distressing sense of inner restlessness. Dystonia, an abnormal muscle contraction Pseudoparkinsonism, symptoms that are similar to what people with Parkinson's disease experience, including tremulousness and drooling Hyperprolactinaemia (rare for those treated with clozapine, quetiapine and aripiprazole), which can cause: Galactorrhoea, the unusual secretion of breast milk. Gynaecomastia, abnormal growth of breast tissue Sexual dysfunction (in both sexes) Osteoporosis Orthostatic hypotension Weight gain (particularly prominent with clozapine, olanzapine, quetiapine and zotepine, can be counteracted by starting the drug with metformin) Antipsychotic medication-induced weight gain (AIWG) is a difficult-to-manage condition. In a meta-analysis analyzing data from 9 studies having more than 40,000 patients with AIWG, use of semaglutide was on an average was associated with 7.37kg weight loss with a good reduction in waist circumference. The occurrence of psychiatric adverse events was lower in semaglutide users.

The right side of a positive-sensed AAV genome encodes overlapping sequences of three capsid proteins, VP1, VP2 and VP3, and two accessory proteins, MAAP & AAP, which start from one promoter, designated p40. The molecular weights of these proteins are 87, 72 and 62 kiloDaltons, respectively. The AAV capsid is composed of a mixture of VP1, VP2, and VP3 totaling 60 monomers arranged in icosahedral symmetry in a ratio of 1:1:10, with an empty mass of approximately 3.8 MDa. The crystal structure of the VP3 protein was determined by Xie, Bue, et al.

Sources: en.wikipedia.org

Background from the literature

Other automotive engineers include those listed below: Aerodynamics engineers will often give guidance to the styling studio so that the shapes they design are aerodynamic, as well as attractive. Body engineers will also let the studio know if it is feasible to make the panels for their designs. Change control engineers make sure that all of the design and manufacturing changes that occur are organized, managed and implemented... NVH engineers perform sound and vibration testing to prevent loud cabin noises, detectable vibrations, and/or improve the sound quality while the vehicle is on the road.

Pseudoenzymes are variants of enzymes that are catalytically-deficient (usually inactive), meaning that they perform little or no enzyme catalysis. They are believed to be represented in all major enzyme families in the kingdoms of life, where they have important signaling and metabolic functions, many of which are only now coming to light. Pseudoenzymes are becoming increasingly important to analyse, especially as the bioinformatic analysis of genomes reveals their ubiquity. Their important regulatory and sometimes disease-associated functions in metabolic and signalling pathways are also shedding new light on the non-catalytic functions of active enzymes, of moonlighting proteins, the re-purposing of proteins in distinct cellular roles (Protein moonlighting). They are also suggesting new ways to target and interpret cellular signalling mechanisms using small molecules and drugs. The most intensively analyzed, and certainly the best understood pseudoenzymes in terms of cellular signalling functions are probably the pseudokinases, the pseudoproteases and the pseudophosphatases. Recently, the pseudo-deubiquitylases have also begun to gain prominence.

The major limitation in the development of artificial WBCs is the translation of the technologies into clinical approval and use. Other limitations include the availability of technology necessary to produce artificial WBCs, variability in yield, and difficulties in purifying the particles necessary for standard clinical use. Some studies have also found that these particles may unintentionally target other tissues that are otherwise healthy. The delivery of the therapies faces some difficulties in that too rapid administration might cause systemic side effects, whereas a too slow release would be less effective. A major limitation to polymersomes is that a select number of polymers such as polyethylene glycol and poly(lactic-co-glycolic acid) are approved by the FDA for clinical use. Nanoghosts, or more generally membrane-coated nanoparticles, experience limitations in that cells will have varying degrees of proteins present in their membranes, creating variability and lack of stability in those products. There also is the risk that membrane proteins essential to the biomimetic function of the nanoghosts can become denatured in the manufacturing and storage process. Overall, more studies need to be done on these biomimetic solutions to verify efficacy and safety.

Studies indicate that a substantial part of the modern vehicle's value comes from intelligent systems, and that these represent most of the current automotive innovation. To facilitate this, the modern automotive engineering process has to handle an increased use of mechatronics. Configuration and performance optimization, system integration, control, component, subsystem and system-level validation of the intelligent systems must become an intrinsic part of the standard vehicle engineering process, just as this is the case for the structural, vibro-acoustic and kinematic design. This requires a vehicle development process that is typically highly simulation-driven.

Sources: en.wikipedia.org

Reference notes

The use of a solvent gradient is very well developed in column chromatography but is less common in CCC. A solvent gradient is produced by increasing (or decreasing) the polarity of the mobile phase during the separation to achieve optimal resolution across a wider range of polarities. For example, a methanol-water mobile phase gradient may be employed using heptane as the stationary phase. This is not possible with all biphasic solvent systems, due to excessive loss of stationary phase created by disruption the equilibrium conditions within the column. Gradients may either be produced in steps, or continuously. In dual-mode, the mobile and stationary phases are reversed part way through the separation experiment. This requires changing the phase being pumped through the column as well as the direction of flow. Dual-mode operation is likely to elute the entire sample from the column but the order of elution is disrupted by switching the phase and direction of flow.

Nevertheless, the resistance of extracellular matrix proteins to proteolysis renders their advanced glycation end products less conducive to being eliminated. While the AGE free adducts are released directly into the urine, AGE peptides are endocytosed by the epithelial cells of the proximal tubule and then degraded by the endolysosomal system to produce AGE amino acids. It is thought that these acids are then returned to the kidney's inside space, or lumen, for excretion. AGE free adducts are the major form through which AGEs are excreted in urine, with AGE-peptides occurring to a lesser extent but accumulating in the plasma of patients with chronic kidney failure. Larger, extracellularly derived AGE proteins cannot pass through the basement membrane of the renal corpuscle and must first be degraded into AGE peptides and AGE free adducts. Peripheral macrophage as well as liver sinusoidal endothelial cells and Kupffer cells have been implicated in this process, although the real-life involvement of the liver has been disputed.

Ansuvimab is a monoclonal antibody therapy that is infused intravenously into people with Ebola virus disease. Ansuvimab is a neutralizing antibody, meaning it binds to a protein on the surface of Ebola virus that is required to infect cells. Specifically, ansuvimab neutralizes infection by binding to a region of the Ebola virus envelope glycoprotein that, in the absence of ansuvimab, would interact with virus's cell receptor protein, Niemann-Pick C1 (NPC1). This "competition" by ansuvimab prevents Ebola virus from binding to NPC1 and "neutralizes" the virus's ability to infect the targeted cell.

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.

What is cardarine?

Cardarine is a common name for GW501516, a synthetic PPARδ agonist developed for research. It has not been approved as a medication in any country. It is classified as an unapproved drug and a prohibited substance in sport.

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