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Cardarine Identity And Mechanism — Quick Reference

By Editorial Desk · published 2025-09-22 · last reviewed 2025-10-27 · Info

anti-doping 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.

Updated 2025-10-27. Numbers and descriptions here follow the published literature rather than marketing material.

Cardarine Identity and Mechanism

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.

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.

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.

Cardarine at a glance

PropertyValueNotes
Common nameCardarineAlso called GW501516 and endurobol.
Chemical formulaC21H18F3NO3S2Molecular weight about 453.5 g/mol.
AppearanceWhite to off-white solidForm depends on synthesis and purity.
SolubilitySoluble in DMSO and ethanolLow solubility in water.
Typical storage-20 °C, desiccated, protected from lightCommon for research chemicals.

Detection, Stability, and Quality

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.

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.

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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.

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.

Identity and Pharmacological Mechanism

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.

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.

Background and Research Context

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.

Supporting material

=== MMPs regulation === Under physiological conditions, MMPs are regulated at five levels: transcription; activation of zymogen precursors; interaction with ECM components; inhibition by TIMPs; and regulated absorption/elimination of active proteases from the extracellular environment. The majority of the literature is based on an investigation of transcriptional level (level 1) modifications, which lacks information on the physiologically relevant actions and control of secreted and post-translationally activated proteases. Future study could focus on the post-transcriptional regulation of MMP activity, especially in vivo.

Alprazolam is taken orally, and is absorbed well – 80% of alprazolam binds to proteins in the serum (the majority binding to albumin). The concentration of alprazolam peaks after one to two hours. Alprazolam is metabolized in the liver, mostly by the cytochrome enzyme CYP3A4. Two major metabolites are produced: 4-hydroxyalprazolam and α-hydroxyalprazolam, as well as an inactive benzophenone. The low concentrations and low potencies of 4-hydroxyalprazolam and α-hydroxyalprazolam indicate that they have little to no contribution to the effects of alprazolam. The metabolites and some unmetabolized alprazolam are filtered out by the kidneys and are excreted in the urine.

== Further reading == Kwatra SG, Yosipovitch G, Legat FJ, Reich A, Paul C, Simon D, et al. (October 2023). "Phase 3 Trial of Nemolizumab in Patients with Prurigo Nodularis". The New England Journal of Medicine. 389 (17): 1579–1589. doi:10.1056/NEJMoa2301333. hdl:1854/LU-01JMVNTYQXH55FHHB47BSMETXX. PMID 37888917. Silverberg JI, Wollenberg A, Reich A, Thaçi D, Legat FJ, Papp KA, et al. (August 2024). "Nemolizumab with concomitant topical therapy in adolescents and adults with moderate-to-severe atopic dermatitis (ARCADIA 1 and ARCADIA 2): results from two replicate, double-blind, randomised controlled phase 3 trials". Lancet. 404 (10451): 445–460. doi:10.1016/S0140-6736(24)01203-0. PMID 39067461.

Sources: en.wikipedia.org

Notes from published material

== Education == MD, 1996, School of Medicine, University of Ljubljana MS, 1998, School of Medicine, University of Ljubljana with thesis "Effects of chromium on blood pressure in humans" PhD, 2000, Diabetology School of Medicine, University of California, San Diego, with thesis Mechanism of glucose transport in insulin resistant 3T3-L1 adipocytes Post doctoral, 2005, Joslin Diabetes Clinic, Boston, study on insulin pump therapy in type 1 diabetic patients

Japan imports US$3.6 million of New Zealand blackcurrants for uses as dietary supplements, snacks, functional food products and as quick-frozen (IQF) produce for culinary production as jams, jellies or preserves.

Their subsequent work shows how the SREBP pathway regulates the expression of many genes that control lipid formation and metabolism and body fuel allocation. Cholesterol synthesis can be turned off when cholesterol levels are high. HMG-CoA reductase contains both a cytosolic domain (responsible for its catalytic function) and a membrane domain which senses signals for its degradation. Increasing concentrations of cholesterol (and other sterols) cause a change in this domain's oligomerization state, making it more susceptible to destruction by the proteasome. This enzyme's activity can also be reduced by phosphorylation by an AMP-activated protein kinase. Because this kinase is activated by AMP, which is produced when ATP is hydrolyzed, it follows that cholesterol synthesis is halted when ATP levels are low.

In October 2025, Moore blamed Trump for the 2025 United States federal government shutdown while urging him to end the shutdown, saying that Maryland would likely face "serious damage" as the shutdown continued through infrastructure project delays, federal employees not receiving pay, and small businesses losing revenue. At the same time, he said that he would work with state companies to protect federal workers impacted by the government shutdown and directed state agencies to deploy contingency plans to keep federally funded programs continually operating. Moore initially declined to provide state funding to fund the Supplemental Nutrition Assistance Program (SNAP) after the U.S. Department of Agriculture (USDA) declined to use its contingency fund to continue funding SNAP, but later signed an order declaring a state of emergency and providing $10 million in funds to assist food banks across Maryland. After the Trump administration said it would only partially fund SNAP food benefits following a federal court ruling ordering it to pay SNAP benefits out of the USDA's contingency fund, Moore signed an executive order providing $62 million in state funds to provide SNAP participants with full benefits during the month of November. In November 2025, Moore criticized the bipartisan Senate agreement to end the shutdown, saying that it was "completely unacceptable" to pass a bill ending the shutdown without extending healthcare subsidies.

Sources: en.wikipedia.org

Further detail

Oveporexton, sold under the brand name Orzeyful, is a medication used for the treatment of narcolepsy type 1. It is taken by mouth. The most common side effects include insomnia, increased urinary frequency, urgency to urinate, and increased saliva production. Oveporexton is an orexin OX2 receptor agonist. Oveporexton was approved for medical use in China in July 2026, and in the United States in August 2026. It is recommended for scheduling under the Controlled Substances Act and will be lawful to market in the US following the scheduling decision issued by the Drug Enforcement Administration.

=== Sympathetic skin response === Sympathetic skin response (SSR) refers to the change in skin resistance to electrical conduction associated with the sympathetic activation of sudomotor function in response to external or internal stimuli, such as electrical stimulation, deep breathing, and mental stress. It is mediated by a poorly understood somato-sympathetic reflex with spinal, bulbar, and suprabulbar components. The SSR is frequently utilized in psychophysiological studies and is a well-known component of the polygraph test. The test is performed using standard electromyography (EMG) equipment in a lightly dimmed, humidity- and temperature-controlled room. A surface electrode is positioned on the patient's palm or sole, along with a reference electrode on the dorsal side of the same body area. A change in skin potential is then induced either through electrical stimulation or deep breathing. The recorded SSR is then plotted on a graph and analyzed for presence or absence, latency, and amplitude. The SSR is thought to be mainly influenced by the electrolyte content of sweat secreted from eccrine glands. In addition, there is significant intra-individual and inter-individual variability, and SSR declines with age and is commonly absent in individuals over the age of 50. SSR is only considered a surrogate marker of sudomotor function and its results should be interpreted in the context of other sudomotor testing.

== History == Frederick L. "Freddy" Simon grew up in Colwich, Kansas, near Wichita. He was a World War II veteran, joining the U.S. Army infantry in 1943 and serving in the 1st Cavalry Division. He was awarded the Purple Heart due to combat wounds sustained in the Pacific Theater, as well as a Bronze Star for valor. After the war, Simon worked for the same company in the hospitality industry for 55 years, building connections with many restaurateurs. Freddy lent his name to, and was a business partner in, a Simon family-owned restaurant called Freddy's Frozen Custard & Steakburgers. Founded by his sons Randy and Bill and Bill's friend, restaurateur Scott Redler, the first location opened in Wichita on August 26, 2002. Freddy's quickly gained a loyal customer base, leading to further expansion beginning in 2004. Freddy's menu has remained consistent over the years, offering signature steakburgers, Vienna Beef hot dogs, and fresh frozen custard desserts across all locations. The food was based on "All American" meals that Freddy had served his own family, with the setting of the restaurant based on fast-casual dining of the late 1940s and early 1950s, evoking "a post-war era of optimism, pride, and values focusing on unity and quality family time." On December 17, 2016, Freddy's co-founder Bill Simon died at the age of 61 after a battle with cancer. Freddy Simon died at the age of 95 on October 25, 2020. In March 2021, private equity firm Thompson Street Capital Partner purchased Freddy's Frozen Custard & Steakburgers for an undisclosed amount.

He has received 17 honorary degrees from institutions including Johns Hopkins and Yale University. In 1987 Hood shared the Albert Lasker Award for Basic Medical Research with Philip Leder and Susumu Tonegawa for studies of the mechanism of immune diversity. He subsequently was awarded the Dickson Prize in 1988. In 1987, Hood also received the Golden Plate Award of the American Academy of Achievement. He won the 2002 Kyoto Prize for Advanced Technology for developing automated technologies for analyzing proteins and genes; the 2003 Lemelson-MIT Prize for Innovation and Invention for inventing "four instruments that have unlocked much of the mystery of human biology" by helping decode the genome; the 2004 Biotechnology Heritage Award; the 2004 Association for Molecular Pathology Award for Excellence in Molecular Diagnostics the 2006 Heinz Award in Technology, the Economy and Employment, for breakthroughs in biomedical science on the genetic level; inclusion in the 2007 Inventors Hall of Fame for the automated DNA sequencer; the 2008 Pittcon Heritage Award for helping to transform the biotechnology industry; and the 2010 Kistler Prize for contributions to genetics that have increased knowledge of the human genome and its relationship to society. Leroy Hood won the 2011 Fritz J. and Dolores H.

Also, no evidence exists that rBST use has increased human exposure to antibiotic residues in milk. Concerns that IGF-1 present in milk could have biological effects on humans have been allayed by studies showing that oral consumption of IGF-1 by humans has little or no biological activity. Additionally, concentrations of IGF-1 in digestive tract fluids of humans far exceed any IGF-1 consumed when drinking milk. Furthermore, chronic supplementation of cows with rBST does not increase concentrations of milk IGF-1 outside the range typically observed for effects of farm, parity, or stage of lactation. Use of rBST has not affected expression of retroviruses in cattle or posed an increased risk to human health from retroviruses in cattle. Furthermore, risk for development of type 1 or type 2 diabetes mellitus has not increased in children or adults consuming milk and dairy products from rBST-supplemented cows. Overall, milk and dairy products provide essential nutrients and related benefits in health maintenance and the prevention of chronic diseases." Keeping in mind that bovine somatotropin is a protein growth hormone, it can increase average milk yield anywhere from 10 to 15%, which in turn would lead to cows consuming substantially more nutrients in order to keep up with the increased milk production. Most of a cow's energy consumption goes directly towards milk production.

Sources: en.wikipedia.org

Frequently asked questions

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.

How does cardarine work?

It activates PPARδ, a nuclear receptor that influences gene expression related to lipid and energy metabolism. Animal studies show changes in endurance and lipid levels. Human effects and risks are not well established.

Is cardarine a steroid?

No, cardarine is not a steroid. It belongs to a different chemical class, the PPARδ agonists. It is also not a selective androgen receptor modulator.

What receptor does cardarine target?

Cardarine targets PPARδ, a nuclear receptor involved in lipid and energy metabolism. It does not bind the androgen receptor in the way SARMs do.

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