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Background And Research Context — Questions and Answers

By Editorial Desk · published 2025-12-17 · last reviewed 2026-01-23 · Topic

This is a working overview of PPARδ agonist, written for readers who want more than a one-paragraph summary but less than a textbook.

This page was last updated on 2026-01-23 and is reviewed periodically as new material appears.

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.

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.

Detection, Stability, and Quality

Quality assessment for cardarine samples usually combines identity, purity, and impurity testing. Nuclear magnetic resonance spectroscopy and mass spectrometry can confirm molecular structure, while high-performance liquid chromatography estimates purity. Certificates of analysis from testing laboratories may list these results, but they do not establish safety or legality. In the absence of approved manufacturing, products sold online may contain the wrong compound, variable amounts, or unlisted contaminants. Independent verification is therefore central to analytical work and to interpreting any reported biological activity.

Laboratory detection of GW501516 commonly uses liquid chromatography coupled with tandem mass spectrometry. The method can identify the parent compound or its metabolites in urine and blood after sample cleanup. Protein precipitation, solid-phase extraction, or enzymatic hydrolysis may precede analysis, depending on the matrix. Reference standards are required for accurate quantification and confirmation. Because the compound is not approved, testing often occurs in anti-doping, forensic, or research settings rather than routine clinical care. Results are reported with limits of detection and quantification.

Stability of GW501516 depends on form, temperature, light exposure, and moisture. Solid reference material is typically stored frozen or refrigerated in a desiccator and protected from light. Solutions in organic solvents such as dimethyl sulfoxide are often kept frozen in aliquots to reduce freeze-thaw cycling. Aqueous solubility is low, so aqueous stock solutions can be difficult to prepare without cosolvents. Degradation may appear as changes in chromatographic purity or mass spectral signal. Stability studies are needed to establish shelf life for any specific preparation.

Cardarine at a glance

PropertyValueNotes
CAS Registry Number317318-70-0Unique identifier for the compound.
Chemical classPPARδ agonistSynthetic ligand for peroxisome proliferator-activated receptor delta.
AppearanceWhite to off-white solidTypical form of research-grade material.
SolubilitySoluble in DMSO and ethanolPoorly soluble in water.
Typical storage-20°CRecommended for long-term storage of 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 Safety Research

Literature on cardarine often separates receptor pharmacology from toxicology. Mechanistic papers describe PPARδ activation and gene expression changes, while safety assessments focus on carcinogenicity and species differences. Questions remain about whether rodent tumors arise through PPARδ-dependent or off-target mechanisms. Another open area is how human metabolism and exposure compare with those in animal studies. Analytical methods such as liquid chromatography–mass spectrometry are used to confirm identity in biological and product samples.

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.

Mechanism and Laboratory Detection

Laboratory handling focuses on identity, purity, and stability. Reference standards are typically stored cold and dry, protected from light, because solutions can degrade over time. Analytical checks may use high-performance liquid chromatography with ultraviolet detection or mass spectrometry. Impurities and related substances can be separated chromatographically and compared with a known standard. Because cardarine is not an approved drug, compendial monographs are absent, and laboratories often rely on in-house methods. Reported purity varies among unregulated products and should not be assumed from a label.

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.

Identity and Regulatory Status

Clinical development stopped after rodent studies showed tumors at multiple sites. Whether those findings predict human cancer risk remains an open question, but they led sponsors to discontinue programs. Human safety data are limited to small, short-term studies that were not designed to assess cancer risk. Reported effects in those studies included changes in blood lipids, but the evidence is insufficient for medical use. Long-term consequences of nonmedical use are not well characterized. Questions about dose, duration, and individual susceptibility remain unresolved.

Cardarine is a common name for GW501516, an investigational compound developed in the 1990s for metabolic conditions. It acts as an agonist at peroxisome proliferator-activated receptor delta, a nuclear receptor involved in lipid and energy metabolism. The compound is frequently mislabeled as a selective androgen receptor modulator, or SARM, but its molecular target is different. GW501516 reached early clinical testing before development was discontinued. It has no approved therapeutic use in any country. The name cardarine is not a formal international nonproprietary name.

Regulatory treatment varies, but cardarine is not approved as a medicine. Sports authorities list GW501516 as a prohibited substance, and it is banned at all times under the World Anti-Doping Agency code. Many countries restrict sales for human consumption, while online vendors market it as a research chemical. Such products may lack purity data, and their actual contents can differ from the label. Purchasing or possessing cardarine may carry legal consequences depending on jurisdiction. The compound is not a dietary supplement ingredient in regulated markets.

Further detail

Affecting generosity by increasing empathy during perspective taking: In a neuroeconomics experiment, intranasal oxytocin increased generosity in the Ultimatum Game by 80%, but had no effect in the Dictator Game that measures altruism. Perspective-taking is not required in the Dictator Game. However, the researchers in this experiment explicitly induced perspective-taking in the Ultimatum Game by not informing participants which role they would be placed. Serious methodological questions have arisen, however, about the role of oxytocin in trust and generosity. Empathy in healthy males is increased after intranasal oxytocin This is most likely due to the effect of oxytocin in enhancing eye gaze. There is some discussion about which aspect of empathy oxytocin might alter – for example, cognitive vs. emotional empathy. While studying wild chimpanzees, it was noted that after a chimpanzee shared food with a non-kin related chimpanzee, the subjects' levels of oxytocin increased, as measured through their urine. In comparison to other cooperative activities between chimpanzees that were monitored, including grooming, food sharing generated higher levels of oxytocin. This comparatively higher level of oxytocin after food sharing parallels the increased level of oxytocin in nursing mothers, sharing nutrients with their kin. Trust is increased by oxytocin. Study found that with the oxytocin nasal spray, people place more trust to strangers in handling their money. Disclosure of emotional events is a sign of trust in humans.

Typical antipsychotics Chlorpromazine Haloperidol Haloperidol functions by blocking the KCNH2 channel, the same pathway that other drug-inducing LQTS block. Patients taking haloperidol are at a higher risk if they also have electrolyte abnormalities (such as hypokalemia and/or hypomagnesemia), congenital LQTS, cardiac abnormalities, hypothyroidism, or if they are concurrently taking other medications known to lengthen the QT interval. Sulpiride Thioridazine (especially high risk; withdrawn by the manufacturer for this precise reason) Atypical antipsychotics Amisulpride Quetiapine Overdoses on quetiapine cause QT prolongation in patients with cardiac risks. Risperidone Mild QT prolongation can be caused by risperidone but there are no specific drug warnings associated with this. Sertindole Ziprasidone SSRIs An EKG is recommended before patients are prescribed SSRI agents citalopram and escitalopram if the prescribed dose is above 40 mg or 20 mg per day, respectively. Fluoxetine Paroxetine Sertraline SNRIs Venlafaxine Tricyclic antidepressants Amitriptyline Desipramine Doxepin Imipramine

If these viruses each contain an RNA segment with a lethal damage, multiple infection can lead to reactivation providing that at least one undamaged copy of each virus gene is present in the infected cell. This phenomenon is known as "multiplicity reactivation". Multiplicity reactivation has been reported to occur in influenza virus infections after induction of RNA damage by UV-irradiation, and ionizing radiation.

For amino acids with uncharged side-chains the zwitterion predominates at pH values between the two pKa values, but coexists in equilibrium with small amounts of net negative and net positive ions. At the midpoint between the two pKa values, the trace amount of net negative and trace of net positive ions balance, so that average net charge of all forms present is zero. This pH is known as the isoelectric point pI, so pI = ⁠1/2⁠(pKa1 + pKa2). For amino acids with charged side chains, the pKa of the side chain is involved. Thus for aspartate or glutamate with negative side chains, the terminal amino group is essentially entirely in the charged form −NH+3, but this positive charge needs to be balanced by the state with just one C-terminal carboxylate group is negatively charged. This occurs halfway between the two carboxylate pKa values: pI = ⁠1/2⁠(pKa1 + pKa(R)), where pKa(R) is the side chain pKa. Similar considerations apply to other amino acids with ionizable side-chains, including not only glutamate (similar to aspartate), but also cysteine, histidine, lysine, tyrosine and arginine with positive side chains. Amino acids have zero mobility in electrophoresis at their isoelectric point, although this behaviour is more usually exploited for peptides and proteins than single amino acids. Zwitterionic amino acids exhibit minimal solubility at their isoelectric point, and in some cases can be isolated from aqueous solution by adjusting the pH to the appropriate isoelectric value.

=== Synthesis === A number of methods of synthesis have also been reported. One method begins with alkylation of 1-(2-pyrimidyl)piperazine (1) with 3-chloro-1-cyanopropane (4-chlorobutyronitrile) (2) to give (3). Next, reduction of the nitrile group is performed either by catalytic hydrogenation or with lithium aluminium hydride (LAH) giving (4). The primary amine is then reacted with 3,3-tetramethyleneglutaric anhydride (5) in order to yield buspirone (6).

Sources: en.wikipedia.org

Supporting material

Terlipressin, sold under the brand name Terlivaz among others, is an analogue of vasopressin used as a vasoactive drug in the management of low blood pressure. It has been found to be effective when norepinephrine does not help. Terlipressin is a vasopressin receptor agonist. Terlipressin was approved for medical use in the United States in 2022. The US Food and Drug Administration (FDA) considers it to be a first-in-class medication.

In addition, Carlos Menem is often accused of having an anti-Peruvian attitude after selling weapons to Ecuador when it was in a war against Peru, generating another accusation of treason against Peruvians after the help that Peruvians gave to Argentina in the Malvinas War. Between 1995 and 2010, diplomatic relations between Argentina and Peru remained frozen at their lowest historical point. Although later the Government of Argentina ended up expressing its reparation to the Peruvian State for this action. While some Peruvian newspapers concluded that Cristina Fernández had complied with what was morally due to the claims of dignity in Peruvian society with those words, other newspapers considered that this had not been enough, coming to suspect a possible camouflaged anti-Peruvian conduct. Examples of such tendencies could be seen in the newspaper Correo, on whose cover the headline "He did not ask for forgiveness" would appear, later pointing out that "Fernández was very cautious in his speech and only used the word 'reparation' in allusion to the questioned sale of arms to Ecuador". Another case was that of Peru 21, which considered that in reality the Argentine president "almost asked for forgiveness".

== Academic career == After Edlich completed his 8-year residency training at the University of Minnesota Hospital, he completed a 2-year plastic surgical residency at the University of Virginia Health Sciences Center. During his time at the University of Virginia School of Medicine, both in his residency and subsequent career, he published hundreds of publications and book chapters on burn care, wound healing, surgical instrument design, and rehabilitation. He began his research career at the University of Virginia Health Sciences Center and was involved in the development of the burn unit and prehospital care service.

== Poor usage of Iran's agricultural land == Approximately one-third of Iran's total surface area consists of arable farmland; however, less than one-fourth of this—equivalent to about one-tenth of the total land area—is actively cultivated. This limited cultivation is due to poor soil quality and inadequate water distribution across many regions. Of the cultivated land, less than one-third benefits from irrigation, while most rely on dry farming techniques. The most fertile soils are found in the western and northwestern regions of the country.

Sources: en.wikipedia.org

Frequently asked questions

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.

Is cardarine a steroid?

No. Cardarine is not an anabolic steroid; it belongs to a different chemical class that targets PPARδ. Steroids act primarily through androgen receptors, while cardarine acts through a nuclear receptor involved in metabolism.

What did animal studies find?

Some rodent studies reported increased endurance and changes in fat metabolism after cardarine exposure. Long-term studies in animals also raised concerns about cancer in certain tissues. Human trial data are limited, so these findings cannot be directly translated to people.

How is cardarine measured in biological samples?

LC-MS/MS is common, often after sample cleanup. The assay targets GW501516 or its metabolites.

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