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Background And Regulatory History — Background and Details

By Editorial Desk · published 2025-12-06 · last reviewed 2025-12-23 · Faq

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

This page was last updated on 2025-12-23 and is reviewed periodically as new material appears.

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.

Cardarine Identity and Mechanism

Published literature on cardarine includes in vitro assays, rodent experiments, and a small number of human studies. Reports describe effects on exercise capacity and lipid metabolism in animals, while human evidence is sparse. Many online descriptions present the compound as a proven endurance aid, a claim not supported by regulatory approval or large clinical trials. Analytical studies focus on identifying the parent compound and its metabolites in biological samples. Important uncertainties include species differences, dose-response relationships, and the relevance of rodent tumor findings to humans.

Cardarine is the common name for GW501516, a synthetic compound studied as a peroxisome proliferator-activated receptor delta agonist. Researchers developed it to explore treatments for lipid disorders and metabolic conditions. It is not an approved medicine in any country. Early clinical work examined changes in HDL cholesterol and triglycerides, but development was discontinued after animal studies raised concerns about cancer. The compound remains available as a research chemical and appears in discussions of performance enhancement.

At the molecular level, GW501516 binds and activates PPARδ, a nuclear receptor that regulates transcription. Activation shifts expression of genes involved in fatty acid oxidation, energy expenditure, and lipid transport in skeletal muscle and liver. Animal studies report increased endurance and altered lipid profiles after exposure. Human data are limited to small trials and do not establish long-term safety or efficacy. PPARδ also has roles in cell proliferation, so the relationship between activation and cancer risk remains an open question.

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.

Mechanism and Detection Methods

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.

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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.

Regulation and Detection

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.

Anti-doping laboratories identify GW501516 and related metabolites using liquid chromatography coupled with tandem mass spectrometry. Urine is the most common matrix, though blood and dried blood spots may also be analyzed. The method targets the parent compound and phase I and phase II metabolites, which extend the detection window. Because the substance is prohibited at all times, athletes can be tested outside competition. Detection limits and windows depend on the assay, sample type, and individual metabolism.

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.

Supporting material

Peroxisomes are microbodies bounded by a single membrane. A peroxisome has no DNA or ribosomes and the proteins that it needs are encoded in the nucleus, and selectively imported from the cytosol. Some proteins enter via the endomembrane reticulum. They have enzymes that rid the cell of toxic peroxides. The enzymatic content of the peroxisomes varies widely across the species, as it can in an individual organism. The peroxisomes in animal cells are concentrated in the liver cells and adipocytes.

The enzyme UDP-glucose 4-epimerase (EC 5.1.3.2), also known as UDP-galactose 4-epimerase or GALE, is a homodimeric epimerase found in bacterial, fungal, plant, and mammalian cells. This enzyme performs the final step in the Leloir pathway of galactose metabolism, catalyzing the reversible conversion of UDP-galactose to UDP-glucose. GALE tightly binds nicotinamide adenine dinucleotide (NAD+), a co-factor required for catalytic activity. Additionally, human and some bacterial GALE isoforms reversibly catalyze the formation of UDP-N-acetylgalactosamine (UDP-GalNAc) from UDP-N-acetylglucosamine (UDP-GlcNAc) in the presence of NAD+, an initial step in glycoprotein or glycolipid synthesis.

==== Union of Lublin ==== The Union of Lublin of 1569 established the Polish–Lithuanian Commonwealth, a federal state more closely unified than the earlier political arrangement between Poland and Lithuania. The union was run largely by the nobility through the system of central parliament and local assemblies, but was headed by elected kings. The formal rule of the nobility, who were proportionally more numerous than in other European countries, constituted an early democratic system ("a sophisticated noble democracy"), in contrast to the absolute monarchies prevalent at that time in the rest of Europe. The beginning of the Commonwealth coincided with a period in Polish history when great political power was attained and advancements in civilization and prosperity took place. The Polish–Lithuanian Union became an influential participant in European affairs and a vital cultural entity that spread Western culture (with Polish characteristics) eastward. In the second half of the 16th century and the first half of the 17th century, the Commonwealth was one of the largest and most populous states in contemporary Europe, with an area approaching one million square kilometres (0.39 million square miles) and a population of about ten million. Its economy was dominated by export-focused agriculture. Nationwide religious toleration was guaranteed at the Warsaw Confederation in 1573.

E. × cantabrigiense Stearn, hybrid between E. alpinum and E. pubigerum E. × perralchicum Stearn, hybrid between E. perralderianum and E. pinnatum subsp. colchicum E. × rubrum Morr., hybrid between E. alpinum and E. grandiflorum E. × versicolor Morr., hybrid between E. grandiflorum and E. pinnatum subsp. colchicum E. × warleyense Stearn, hybrid between E. alpinum and E. pinnatum subsp. colchicum E. × youngianum Fisch & C.A.Mey, hybrid between E. diphyllum and E. grandiflorum

Plasma levels of progesterone are similar after vaginal and rectal administration in spite of the different routes of administration, and rectal administration is an alternative to vaginal progesterone in conditions of vaginal infection, cystitis, recent childbirth, or when barrier contraception methods are used. Intramuscular injection of progesterone may achieve much higher levels of progesterone than normal luteal phase concentrations and levels achieved with other routes.

Sources: en.wikipedia.org

Notes from published material

=== 8 February === The SAF claimed to have retaken the Kafouri district of Khartoum Bahri. The SLM and the GSLF launched an incursion into Chad from Darfur, resulting in clashes with the Chadian Army in the vicinity of the tri-border area with Sudan and Libya. Six Sudanese soldiers were killed while 13 others were injured. Three vehicles were also destroyed while two Sudanese commanders were captured and detained at Amdjarass.

== Research == Stem cell therapy may represent a treatment for promoting the healing of diabetic foot ulcers. Diabetic foot ulcers develop their own, distinctive microbiota. Investigations into characterizing and identifying the phyla, genera, and species of nonpathogenic bacteria or other microorganisms populating these ulcers may help identify one group of microbiota that promotes healing. The recent advances in epigenetic modifications, with special focus on aberrant macrophage polarisation, are giving increasing evidence that epigenetic modifications might play a vital role in changing the treatment of diabetic foot ulcer in the near future.

== Side-effects == Many of the side effects of abciximab are due to its anti-platelet effects which increase the risk of bleeding. The most common type of bleeding due to abciximab is gastrointestinal hemorrhage. Thrombocytopenia is a rare but known serious risk characterized by a severe drop in platelets circulating in the blood. Abciximab induced thrombocytopenia is usually rapid occurring hours after administration but may occur up to 16 days later. Transfusing platelets is the only known treatment for abciximab-induced thrombocytopenia, but this therapy may have limited effectiveness because the drug may bind and inhibit the receptors on the newly transfused platelets.

== Historical fiction author == Wilson said of his accomplishments outside of ophthalmology, that writing fiction is a “great pleasure” and a treasured hobby. His first novel, Winter in Kandahar, was a 2004 finalist for the Benjamin Franklin Award for Best New Voice in Fiction. A second novel, Ascent from Darkness, was a finalist in the Action/Adventure category (2008) in the Indie Book Awards. Wilson's third novel, The Ghosts of Anatolia, received multiple awards in 2010 and 2011. A more recent novel, The Benghazi Affair was the Benjamin Franklin Award Audio Book Gold Prize winner in fiction.

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 a common name for the investigational compound GW501516. It acts as a PPARδ agonist and is not approved for human use. It is prohibited in sport.

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