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Background And Regulatory History — Worked Examples

By Editorial Desk · published 2026-05-01 · last reviewed 2026-05-15 · Faq

A practical reference on GW501516: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.

Reviewed 2026-05-15. Anything still debated is marked as such rather than presented as settled.

Background and Regulatory History

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.

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 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.

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.

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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.

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.

Notes from published material

Crystallization of ubiquitin protein was successfully done using racemic crystallography. Crystallization of either D-ubiquitin or L-ubiquitin alone is difficult, whereas a racemic mixture of D-ubiquitin and L-ubiquitin was readily crystallized and diffraction quality crystals were obtained overnight in almost half the conditions tested in a standard commercial crystallization screen. Crystallization of racemates of disulfide-containing microprotein molecules was used to determine the structure of trypsin inhibitor SFTI-1 (14 amino acids,1 disulfide), conotoxin cVc1.1 (22 amino acids, 2 disul-fides) and cyclotide kB1 (29 amino acids, 3 disulfides). Using X-ray diffraction, it was found that the racemates crystallized in the centrosymmetric spacegroups P3(bar), Pbca and P1(bar). Interestingly, achiral "'peptoid'" chains were found to fold as racemic pairs and crystallize in highly preferred centrosymmetric space groups. A high-resolution crystal structure of the racemate of a heterochiral D-protein complex with vascular endothelial growth factor A (VEGF-A). The mirror image D-protein form of VEGF-A was used in phage display to identify a 56 residue L-protein binder with nanomolar affinity; the chemically synthesized D-protein binder had the same affinity for the L-protein form of VEGF-A. A mixture of chemically synthesized proteins consisting of D-VEGF-A, L-VEGF-A, and two equivalents each of the D-protein binder and L-protein binder, gave racemic crystals in the centrosymmetric space group P21/n.

Peak Identification: Before integration, the peaks corresponding to different components in the sample need to be identified, based on their retention times. This is typically done by comparing the observed peaks with known standards or reference data. Baseline Correction: Establish a baseline for the chromatogram, which represents the lowest signal level along the time axis next to the peak. The baseline represents the noise and background signal. Taking into account the baseline level allows an accurate integration, because it takes into account any drift or fluctuations in the baseline. Peak Integration parameters and settings: Use appropriate algorithms to integrate the peaks in the chromatogram. Adjust integration parameters and settings as needed, such as noting peak width, noise threshold, and baseline correction method, which determine where the peak starts and ends and its maximum point. Optimizing these parameters helps obtain accurate and precise integration results. Quantification: Once the areas under the peaks are determined through integration, the quantification of each component is performed. The integrated areas are compared to a calibration curve, created using standards' concentrations to calculate the concentration of each component in the unknown sample. Data Interpretation: The software analyzes the integrated data to draw conclusions about the composition, concentration, and purity of the sample. The integrated areas provide valuable information for various applications, including quality control, research, and analysis.

=== Glycerol intoxication === Excessive consumption by children can lead to glycerol intoxication. Symptoms of intoxication include hypoglycemia, nausea, and a loss of consciousness. While intoxication as a result of excessive glycerol consumption is rare and its symptoms generally mild, occasional reports of hospitalization have occurred. In the United Kingdom in August 2023, manufacturers of syrup used in slush ice drinks were advised to reduce the amount of glycerol in their formulations by the Food Standards Agency to reduce the risk of intoxication. A 2025 study reported that between 2018 and 2024, at least 21 children aged 2–7 in the UK and Ireland received emergency treatment for symptoms of glycerol intoxication following the consumption of slush ice drinks. Food Standards Scotland advises that slush ice drinks containing glycerol should not be given to children under the age of 4, owing to the risk of intoxication. It also recommends that businesses do not use free refill offers for the drinks in venues where children under the age of 10 are likely to consume them, and that products should be appropriately labelled to inform consumers of the presence of glycerol.

== Documentaries == On 18 August 2023, BBC One broadcast the Panorama documentary Lucy Letby: The Nurse Who Killed, based on reporting by Judith Moritz. In 2024, Channel 5 released two documentaries Lucy Letby: Did She Really Do It? and Letby: The New Evidence. That same year, Moritz and Jonathan Coffey published Unmasking Lucy Letby: The Untold Story of the Killer Nurse. In 2025, ITV broadcast Lucy Letby: Beyond Reasonable Doubt?, while Channel 4 aired two series: Conviction: The Case of Lucy Letby and Lucy Letby: Murder or Mistake. In 2026, Netflix released a feature-length documentary titled The Investigation of Lucy Letby.

Sources: en.wikipedia.org

Background from the literature

=== United States === On 7 February, a US Marine; Lance Cpl Chukwuemeka E. Oforah, fell overboard the USS Iwo Jima. After a search-and-rescue operation was intiated with no body recovered, he was declared dead on 10 February. He is the first known American fatality from Operation Southern Spear.

In chemistry, biochemistry and environmental sciences, deuterium is used as a non-radioactive, stable isotopic tracer, for example, in the doubly labeled water test. In chemical reactions and metabolic pathways, deuterium behaves somewhat similarly to ordinary hydrogen (with a few chemical differences, as noted). It can be distinguished from normal hydrogen most easily by its mass, using mass spectrometry or infrared spectrometry. Deuterium can be detected by femtosecond infrared spectroscopy, since the mass difference drastically affects the frequency of molecular vibrations; 2H–carbon bond vibrations are found in spectral regions free of other signals. Measurements of small variations in the natural abundances of deuterium, along with those of the stable heavy oxygen isotopes 17O and 18O, are of importance in hydrology, to trace the geographic origin of Earth's waters. The heavy isotopes of hydrogen and oxygen in rainwater (meteoric water) are enriched as a function of the temperature of the region where the precipitation falls (and thus enrichment is related to latitude). The relative enrichment of the heavy isotopes in rainwater (as referenced to mean ocean water), when plotted against temperature falls predictably along a line called the global meteoric water line (GMWL). This plot allows samples of precipitation-originated water to be identified along with general information about the climate in which it originated.

== Organization == JWD and its subsidiaries handle logistics operations including land transport, warehouse and supply chain management, IT solutions for logistics and investment. Its main service is warehouse and yard management, which contributes more than 50 percent of revenue. It specializes in three product areas: automotive and parts, cold chain logistics, and dangerous goods & chemicals. It handles approximately 70% of hazardous substances flowing through the ports of the Port Authority of Thailand.

=== Taxonomic history === In bacterial taxonomy, the basionym for L. d. bulgaricus was "Thermobacterium bulgaricum" Orla-Jensen 1919. The entity became Lactobacillus bulgaricus in 1973 with the work of Rugosa and Hansen, and was reclassified as a subspecies under Lactobacillus delbrueckii in 1984.

Thiopental is still used in some places as a truth serum to weaken the resolve of a subject and make the individual more compliant to pressure. Barbiturates decrease both higher cortical brain function and inhibition. It is thought that because lying is a more involved process than telling the truth, suppression of the higher cortical functions may lead to the uncovering of the truth. The drug tends to make subjects verbose and cooperative with interrogators; however, the reliability of confessions made under thiopental is questionable.

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.

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.

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