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Identity And Pharmacological Classification — Quick Reference

By Editorial Desk · published 2026-03-15 · last reviewed 2026-04-20 · Topic

PPARδ agonist 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.

Last reviewed on 2026-04-20. Where a claim depends on a specific study, the study is described rather than over-claimed.

Identity and Pharmacological Classification

Published studies have examined GW501516 in animal models of obesity, insulin resistance, and exercise endurance. Early human trials reportedly ended, and development was discontinued after preclinical findings raised concerns about cancer in some rodent studies. Regulatory agencies have not approved cardarine for any medical use. Its availability through non-pharmaceutical channels raises questions about identity, purity, and legal status that are separate from its laboratory pharmacology. Those questions are often addressed through analytical testing rather than assumptions about product labels.

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.

Identity and Pharmacological Mechanism

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.

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.

Cardarine at a glance

PropertyValueNotes
Chemical classPPARδ agonistNot an anabolic steroid.
Common synonymsGW501516, GW-1516Cardarine is an informal name.
AppearanceWhite to off-white powderTypical for research-grade solid.
Solubility classPoorly soluble in water; soluble in some organic solventsSuch as DMSO or ethanol in laboratory settings.
Typical storage temperatureCool, dry, protected from lightSpecific conditions vary by supplier and form.

Mechanism and Laboratory Detection

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.

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.

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Detection, Stability, and Quality

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 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.

Background from the literature

Glycerol is a stable preserving agent for botanical extracts that, when utilized in proper concentrations in an extraction solvent base, does not allow inverting or reduction-oxidation of a finished extract's constituents, even over several years. Both glycerol and ethanol are viable preserving agents. Glycerol is bacteriostatic in its action, and ethanol is bactericidal in its action.

=== Calls for regulation and reform === The British Medical Association called for a formal mechanism to hold NHS managers and healthcare administrators accountable for mismanagement, comparable to the General Medical Council's ability to strike off doctors. A neonatal consultant who had raised concerns about Letby also urged the introduction of regulation for healthcare management. The Parliamentary and Health Service Ombudsman, Rob Behrens, said that radical reform of NHS management was needed to prevent similar failures. Dewi Evans called for an investigation into potential corporate manslaughter in relation to the case. Dame Ruth May, NHS England's Chief Nursing Officer, stated that the NHS was committed to learning from the case and welcomed the independent inquiry announced by the Department of Health and Social Care. On 21 August 2023, it was announced that the nursing director at the Countess of Chester Hospital during Letby's employment had been suspended from her subsequent role at Northern Care Alliance NHS Foundation Trust, following information that emerged during the trial. The Nursing and Midwifery Council later confirmed that she would face a fitness‑to‑practise investigation. She and other senior executives at the hospital were accused of failing to act on warnings about Letby.

Vasopressin is regulated by AVP gene expression which is managed by major clock controlled genes. In this circadian circuit known as the transcription-translation feedback loop (TTFL), Per2 protein accumulates and is phosphorylated by CK1E. Per2 subsequently inhibits the transcription factors Clock and BMAL1 in order to reduce Per2 protein levels in the cell. At the same time, Per2 also inhibits the transcription factors for the AVP gene in order to regulate its expression, the expression of vasopressin, and other AVP gene products. Many factors influence the secretion of vasopressin:

== Entactogens == Entactogens are a class of psychoactive drugs that produce distinctive emotional and social effects similar to those of MDMA. Users of entactogens say the drugs often produce feelings of empathy, love, and emotional closeness to others.

Nineteen states require a bear hunting license, with some also requiring a big game license. In eight states, only a big game license is required. Overall, over 481,500 American black bear hunting licenses are sold per year. The hunting methods and seasons vary greatly according to state, with some bear hunting seasons including fall only, spring and fall, or year-round. New Jersey, in November 2010, approved a six-day bear-hunting season in early December 2010 to slow the growth of the population. Bear hunting had been banned in New Jersey for five years before that time. A Fairleigh Dickinson University PublicMind poll found that 53% of New Jersey voters approved of the new season if scientists concluded that bears were leaving their usual habitats and destroying private property. Men, older voters and those living in rural areas were more likely to approve of a bear hunting season in New Jersey than women, younger voters and those living in more developed parts of the state. In the western states, where there are large American black bear populations, there are spring and year-round seasons. Approximately 18,000 American black bears were killed annually in the U.S. between 1988 and 1992. Within this period, annual kills ranged from six bears in South Carolina to 2,232 in Maine. According to Dwight Schuh in his Bowhunter's Encyclopedia, American black bears are the third most popular quarry of bowhunters, behind deer and elk.

Sources: en.wikipedia.org

Reference notes

=== Blood parameters === During acute inflammatory periods, people with AS may show an increase in the blood concentration of CRP and an increase in the ESR, but there are many with AS whose CRP and ESR rates do not increase, so normal CRP and ESR results do not always correspond with the amount of inflammation that is actually present. In other words, some people with AS have normal levels of CRP and ESR, despite experiencing a significant amount of inflammation in their bodies.

Breastfeeding Resources – La Leche League International (archived 6 November 2006) "Breast-Feeding Content Resources" – WHO reports on Breast Feeding "Breastfeeding and Breast Milk" – US National Institute of Health Center for Disease Control and Prevention Breastfeeding Academy of Breastfeeding Medicine The World Alliance for Breastfeeding Action LactMed – a database of the safety of drugs to which breastfeeding mothers may be exposed by the US National Library of Medicine

== Human pathology == Accumulation of excess homogentisic acid and its oxide, named alkapton, is a result of the failure of the enzyme homogentisic acid 1,2-dioxygenase (typically due to a mutation) in the degradative pathway of tyrosine, consequently associated with alkaptonuria.

A calibration first consists of a preliminary test in which the fundamental calibration capability is checked. The quartz control plates must meet the required minimum requirements with respect to their dimensions, optical pureness, flatness, parallelism of the faces and optical axis errors. After that, the actual measurement value - the optical rotation - is measured with the precision polarimeter. The measurement uncertainty of the polarimeter amounts to 0.001° (k=2).

Sources: en.wikipedia.org

Notes from published material

=== Quigley Company asbestos settlement (2013) === The Quigley Company, which sold asbestos-containing insulation products until the early 1970s, was acquired by Pfizer in 1968. In June 2013, asbestos victims and Pfizer negotiated a settlement that required Pfizer to pay a total of $964 million: $430 million to 80% of existing plaintiffs and place an additional $535 million into a settlement trust that will compensate future plaintiffs as well as the remaining 20% of plaintiffs with claims against Pfizer and Quigley. Of that $535 million, $405 million is in a 40-year note from Pfizer, while $100 million is from insurance policies.

Non-pathogenic organisms can become pathogenic given specific conditions, and even the most virulent organism requires certain circumstances to cause a compromising infection. Some colonizing bacteria, such as Corynebacteria sp. and Viridans streptococci, prevent the adhesion and colonization of pathogenic bacteria and thus have a symbiotic relationship with the host, preventing infection and speeding wound healing.

=== The American Revolution === After his disenchantment with socialism, Hitchens increasingly emphasized the centrality of the American Revolution and the U.S. Constitution to his political philosophy. As early as 2002, Hitchens wrote, "as the third millennium gets under way, and as the Russian and Chinese and Cuban revolutions drop below the horizon, it is possible to argue that the American revolution, with its promise of cosmopolitan democracy, is the only 'model' revolution that humanity has left to it". His enthusiasm for the U.S. Bill of Rights contrasts with a dim opinion of constitutional politics on the other side of the Atlantic. Hitchens notes, "the utter failure [of the EU] to compose a viable constitution" and the "brevity of the British constitution, perhaps because the motherland of the English-speaking peoples has absent-mindedly failed to evolve one in written form".

Sources: en.wikipedia.org

Frequently asked questions

What is cardarine also known as?

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.

Is cardarine a steroid?

No, cardarine is not a steroid. It is classified as a PPARδ agonist. Its structure and receptor target differ from anabolic steroids.

Has cardarine been approved for human use?

No regulatory agency has approved cardarine as a medicine. It was investigated in early research but development was discontinued. It is not available as a prescription drug.

What is cardarine?

Cardarine is a common name for GW501516, a synthetic PPARδ agonist. It is not a steroid or a selective androgen receptor modulator. It was developed and studied as a research compound for metabolic pathways.

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