This is a working overview of PPAR delta, written for readers who want more than a one-paragraph summary but less than a textbook.
Reviewed 2026-05-23. Anything still debated is marked as such rather than presented as settled.
GW501516 acts as an agonist at peroxisome proliferator-activated receptor delta, a nuclear receptor involved in transcription of genes related to lipid handling and energy use. Activation of PPARδ can shift skeletal muscle toward greater fatty acid oxidation in animal models, which is one reason it drew interest for metabolic disease and exercise research. The exact downstream effects depend on tissue, species, dose, and duration. Human data are sparse, so many proposed benefits remain hypotheses rather than established clinical outcomes.
Laboratory studies have examined GW501516 in cell cultures and rodents for conditions such as dyslipidemia, insulin resistance, and obesity. Some trials in humans were initiated, but development was discontinued after preclinical findings raised concerns about cancer in certain models. Those findings do not prove that the compound causes cancer in people, but they contributed to regulatory caution. Later reviews often describe the evidence as preliminary and insufficient for assessing long-term safety.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Solubility | Soluble in dimethyl sulfoxide and some organic solvents; practically insoluble in water | Solvent choice affects laboratory handling |
| Typical storage | -20 °C, desiccated, protected from light | Common condition for research samples |
| Analytical method | Liquid chromatography–tandem mass spectrometry (LC-MS/MS) | Used for identification and quantification in biological or product samples |
| Common synonyms | GW501516, GW-501516, GSK-516, Endurobol | Names found in research and anti-doping literature |
| Regulatory status | Unapproved therapeutic; prohibited in competitive sport | Status can vary by country and context |
Safety concerns emerged from long-term animal studies. In rodents given the compound for extended periods, researchers found an increased incidence of certain cancers, including liver and bladder tumors. These findings contributed to the discontinuation of clinical development. Whether similar risks apply to short-term or low-level exposure in humans is not established, and controlled human safety data are limited. The relevance of high-dose rodent carcinogenicity findings to human use remains a subject of debate.
Human trials of GW501516 were small and short in duration. They examined lipid levels, glucose handling, and other metabolic markers, but the programs were halted after the animal cancer findings. No approved therapeutic product exists, and published human data are insufficient for establishing long-term safety. Reports of use for athletic performance come mainly from non-clinical settings and cannot be verified through controlled trials. Independent testing of products sold as cardarine has found inconsistent purity and labeling.
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.
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.
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.
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.
== Structure == Peptoid oligomers are known to be conformationally unstable, due to the flexibility of the main-chain methylene groups and the absence of stabilizing hydrogen bond interactions along the backbone. Nevertheless, through the choice of appropriate side chains it is possible to form specific steric or electronic interactions that favour the formation of stable secondary structures like helices, especially peptoids with C-α-branched side chains are known to adopt structure analogous to polyproline I helix. Different strategies have been employed to predict and characterize peptoid secondary structure, with the ultimate goal of developing fully folded peptoid protein structures The cis/trans amide bond isomerization still leads to a conformational heterogeneity which doesn’t allow for the formation of homogeneous peptoid foldamers. Nonetheless, scientists were able to find trans-inducer N-Aryl side chains promoting polyproline type II helix, and strong cis-inducer such as bulky naphtylethyl and tert-butyl side chains. It was also found that n→π* interactions can modulate the ratio of cis/trans amide bond conformers, until reaching a complete control of the cis conformer in the peptoid backbone using a functionalizable triazolium side chain.
According to the North American Mycological Association (NAMA) however, "[i]n humans, no reliably documented cases of death from toxins in these mushrooms [mushrooms that contain isoxazole derivatives] in the past 100 years, though there is one case where a camper froze to death while in the comatose state".
=== 4 February === Ukrainian officials claimed to have done another prisoner swap with Russia, saying that 116 Ukrainian POWs have been returned, including Ukrainian soldiers and guerrillas from occupied territories. Also returned were the bodies of the two deceased British aid workers killed near Soledar, namely Chris Parry, aged 28, and Andrew Bagshaw, aged 47. Russian officials claimed some 63 soldiers were returned. The deal was in part organised by the United Arab Emirates.
Sources: en.wikipedia.org
Lancashire Police confirm the body found in the River Wyre the previous day is that of Nicola Bulley. 21 February – A planned 48-hour strike by nurses is called off to allow the Royal College of Nursing and Department of Health and Social Care to enter into renewed negotiations. The BMA maintains that junior doctor's pay has been cut by 26% since 2008 after inflation is considered. The UK Government recommends a 3.5% pay rise for public sector workers in England, below the rate of inflation. 22 February – Following a trial at Winchester Crown Court, Shaye Grove, 27, a woman obsessed with serial killers, is sentenced to life imprisonment with a minimum of 23 years for the murder of her boyfriend, who she stabbed to death in July 2022. 23 February – Figures produced by the Office for National Statistics show school absences in England remain above their pre-COVID levels, with 25.1% of pupils regularly absent during the autumn term of 2022 compared to 13.1% in autumn 2019. 24 February – The British Medical Association announces that junior doctors in England will begin a three-day strike on 13 March.
These immobilized CSP are much more rugged and the "non-standard" solvents can be employed. Thus expanding the choice of co-solvent. The major strength of immobilized CSPs are high solvent versatility in selection of mobile phase composition, enhanced sample solubility, high selectivity, robustness and extended durability, excellent column efficiency, and broad application domain in the resolution of enantiomers. Solvent is a key factor in HPLC MD. More solvents to play with means better sample solubility, Improves resolution, and enables effective chiral method development.
== R == r-selection – radiobiology – receptor (biochemistry) – receptor (immunology) – recombination – Red Queen – redox reaction – redox system – reduction – reflex – Renal corpuscle – repeats – replication bubble – repressor – reproduction – reproductive system – respiration (physiology) – restriction enzyme – retrovirus – reverse genetics – RFLP – Rh blood group system – ribosome – RNA – RNA virus – Robert Koch – root – rough ER – RuBP – Rudolf Steiner –
== Use and effects == According to Alexander Shulgin in his book TiHKAL (Tryptamines I Have Known and Loved), 6-HO-DET has been reported to be active at a dose of 10 mg by intramuscular injection. Lower doses of 1 to 2 mg were inactive, whereas 5 mg produced threshold effects. The drug at a dose of 10 mg was said to produce psychedelic effects very similar to those with 60 mg diethyltryptamine (DET), with these effects starting after 1 hour and lasting 2 to 3 hours. Based on this report, the drug would be about 5 to 6 times more potent than DET in humans. However, this report of 6-HO-DET's properties and effects is a second-hand early account in a single subject provided by Stephen Szara and colleagues and has not been replicated. Moreover, it is seemingly inconsistent with the inactivity of the closely related compounds 6-HO-DMT, 6-MeO-DMT, and 6-fluoro-DET. Relatedly, Shulgin wrote in TiHKAL that it is generally accepted that 6-HO-DET is inactive.
Sources: en.wikipedia.org
=== Genetic susceptibility of certain breeds === This list of risk factors for canine diabetes is taken from the genetic breed study that was published in 2007. Their "neutral risk" category should be interpreted as insufficient evidence that the dog breed genetically shows a high, moderate, or a low risk for the disease. All risk information is based only on discovered genetic factors.
=== EC 1.2.2 With a cytochrome as acceptor === EC 1.2.2.1: formate dehydrogenase (cytochrome) EC 1.2.2.2: Now covered by EC 1.2.5.1, pyruvate dehydrogenase (quinone) EC 1.2.2.3: Now EC 1.17.2.3, formate dehydrogenase (cytochrome-c-553) EC 1.2.2.4: Now classified as EC 1.2.5.3, aerobic carbon monoxide dehydrogenase
== Anatomy in visual arts == Gross anatomy has become a key part of visual arts. Basic concepts of how muscles and bones function and deform with movement is key to drawing, painting or animating a human figure. Many books such as Human Anatomy for Artists: The Elements of Form, are written as a guide to drawing the human body anatomically correctly. Leonardo da Vinci sought to improve his art through a better understanding of human anatomy. In the process he advanced both human anatomy and its representation in art. Because the structure of a living organism is complex, anatomy is organized by levels, from the smallest components of cells to the largest organs and their relationship to other organs.
== Materials == Stainless steels, such as Type 304L and 316L, are used extensively in the fabrication of water treatment plants due to their corrosion resistance to water and to the corrosivity of chlorination used for disinfection.
1 March to 8 May The 4th Marine Regiment launched Operation Purple Martin against three PAVN regiments operating near the Vietnamese Demilitarized Zone (DMZ). The operation results in 347 PAVN killed and approximately 100 Marines killed.
Sources: en.wikipedia.org
It binds and activates PPARδ, a nuclear receptor that influences gene expression related to fatty acid metabolism and energy balance. This mechanism has been studied mainly in animals and cell models, not established as a safe human therapy.
No. It is not an anabolic-androgenic steroid; it is a synthetic PPARδ agonist. Because it is banned in sport, it is sometimes grouped with doping agents even though its chemical class differs from steroids.
Human data are limited and development was discontinued, so major effects and long-term risks are not well characterized. Some early studies examined metabolic markers, but they do not provide a basis for unsupervised use.
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.