A practical reference on Reference standard: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
Reviewed 2026-05-10. Anything still debated is marked as such rather than presented as settled.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic PPARδ agonist | Not a steroid or a selective androgen receptor modulator. |
| Common synonyms | Cardarine, GW501516, GW-501516, endurobol | Names vary by supplier and literature source. |
| Appearance | White to off-white powder | Consistent with many small-molecule research chemicals. |
| Solubility | Low in water; soluble in DMSO and ethanol | Often prepared in organic solvent for laboratory work. |
| Primary target | PPARδ (NR1C2) | Nuclear receptor involved in lipid and energy metabolism. |
Literature on cardarine often separates receptor pharmacology from toxicology. Mechanistic papers describe PPARδ activation and gene expression changes, while safety assessments focus on carcinogenicity and species differences. Questions remain about whether rodent tumors arise through PPARδ-dependent or off-target mechanisms. Another open area is how human metabolism and exposure compare with those in animal studies. Analytical methods such as liquid chromatography–mass spectrometry are used to confirm identity in biological and product samples.
GW501516 acts as an agonist at the peroxisome proliferator-activated receptor delta, a nuclear receptor that regulates gene expression. Activation shifts transcription toward genes involved in fatty acid uptake, oxidation, and energy expenditure. The compound does not bind the androgen receptor and therefore differs from anabolic steroids and SARMs. In rodent models, this metabolic shift has been linked to increased running endurance and reduced fat accumulation. The exact downstream pathways in humans remain incompletely characterized.
Early clinical research explored GW501516 for lipid disorders, obesity, and diabetes. Some short-term human studies reported changes in HDL cholesterol, LDL cholesterol, and triglycerides. The development program was discontinued after rodent studies showed dose-dependent tumor formation in multiple tissues, including liver, bladder, stomach, and skin. These findings raised concerns about long-term cancer risk in humans. Because human exposure data are limited, the clinical significance of the rodent tumors remains uncertain.
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.
In the fitness and bodybuilding literature, cardarine is frequently discussed as an endurance agent or fat-loss compound, although such claims are not supported by robust clinical evidence. Online descriptions often mix animal data, user anecdotes, and marketing language. Researchers who study PPARδ agonists distinguish between receptor activation in controlled experiments and unsupervised use of unverified products. The latter introduces unknown purity, dose, and interactions, making reported experiences difficult to interpret scientifically.
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.
Cardarine is explicitly prohibited by the World Anti-Doping Agency under the class of PPARδ agonists. Its presence in urine or blood samples can be detected using mass spectrometry-based methods, often liquid chromatography-tandem mass spectrometry. Athletes who test positive may face sanctions, including bans from competition. The compound is also regulated as a prescription-only or unapproved drug in many countries. Enforcement varies by jurisdiction, and some regions treat it as a controlled substance. Online sales may occur despite these restrictions, creating quality and legal risks.
Laboratory detection of cardarine typically involves sample preparation followed by chromatographic separation and mass spectrometric identification. Urine is the most common matrix for anti-doping tests, though blood and hair have also been explored. Methods can target the parent compound or its metabolites, depending on the expected window of detection. Reference standards are required for accurate quantification. Matrix effects and dilution can influence results, so laboratories use internal standards and validation protocols. The exact detection window varies with dose, route, and individual metabolism.
Myxedema coma is an extreme or decompensated form of hypothyroidism and, while uncommon, is potentially lethal. A person may have laboratory values identical to a "normal" hypothyroid state, but a stressful event (such as an infection, myocardial infarction, or stroke) precipitates the myxedema coma state, usually in the elderly. Primary symptoms of myxedema coma are altered mental status and low body temperature. Low blood sugar, low blood pressure, hyponatremia, hypercapnia, hypoxia, slowed heart rate, and hypoventilation may also occur. Myxedema, although included in the name, is not necessarily seen in myxedema coma. Coma is also not necessarily seen in myxedema coma, as patients may be obtunded without being comatose. According to newer theories, myxedema coma could result from allostatic overload in a situation where the effects of hypothyroidism are amplified by nonthyroidal illness syndrome.
The three main kinds of judgments the Court of Justice gives following (1) preliminary rulings, requested by the courts of member states, (2) enforcement actions, brought by the commission or Member States, against the EU, a member state, or any other party that is alleged to violate EU law, and (3) other direct actions, where the EU or member state is involved as a party to the dispute, and gives final rulings. The Rules of Procedure of the Court of Justice, modelled on the International Court of Justice, begin with submission of written cases to the court, followed by a short oral hearing. In each case a judge is designated to actively manage the hearing (called a rapporteur) and draft the judgment (probably with help from referendaires). The court always deliberates and votes before the final opinion is written and published. Cases in the General Court can be appealed to the Court of Justice on points of law. While there is no formal appeal procedure from the Court of Justice, in practice its actions are subject to scrutiny by both the supreme courts of member states and the European Court of Human Rights, even if the final balance of power is unresolved.
=== International aid === On 8 February 2023, President Lula authorized immediate emergency aid, including several Brazilian fire brigades, Brazilian Air Force air tankers and other emergency services and equipment to be sent to Chile after severe wildfires broke out across the country. In the following day, Brazil sent aid, rescue crews, including search and rescue dogs, among other equipment and staff to Turkey and Syria following the 2023 Turkey-Syria earthquake. In July 2023, Lula also sent Brazilian firefighters teams to Canada to help with the 2023 Central Canada wildfires.
=== LFA-1 and LFA-3–based therapeutics for autoimmune disease === Although Springer made the first antibodies to LFA-1 and LFA-3, he did not patent them. An antibody isolated by Hildreth and McMichael was licensed to Genentech, which was humanized and approved by the FDA in 2003 for moderate to severe psoriasis as Raptiva. Its generic name efalizumab simulate the letters F and L in LFA-1. Springer and lab member Mike Dustin collaborated with Barbara Wallner at Biogen to clone the cDNA for LFA-3. The LFA-3 ectodomain, which contains one immunoglobulin-like domain, was fused to the Fc domain of IgG to create Amevive. Amevive was approved for moderate to severe psoriasis in 2003. Its generic name, alefacept, is a homophone of LFA plus "cept" from receptor. Royalties paid by Biogen to Dana Farber Cancer Institute were equally shared by Dustin and Springer.
== Sources == Magurno, B. A.; Pearlstein, S., eds. (1981). Proceedings of the conference on nuclear data evaluation methods and procedures. BNL-NCS 51363 (PDF). Vol. II. Upton: Brookhaven National Laboratory. Archived (PDF) from the original on March 8, 2021. Retrieved August 6, 2014. Miner, William N.; Schonfeld, Fred W. (1968). "Plutonium". In Clifford A. Hampel (ed.). The Encyclopedia of the Chemical Elements. New York (NY): Reinhold Book Corporation. pp. 540–546. LCCN 68029938.
Sources: en.wikipedia.org
== Animal studies == Infusion of Ucn2 into rat hearts resulted in an immediate and significant improvement in left ventricle function, increased coronary flow, significantly altered intracellular calcium handling and increased SR calcium. These relaxation effects can be explained by the increased calcium clearance into the SR would assist in relaxation of the cell. Increased calcium in the SR by Ucn2 is a result of Ucn2 mediated production of cAMP and phosphokinase A (PKA). Ucn2 increases cAMP levels in myocytes and nonmyocytes. The production of PKA results in the phosphorylation of phospholamban and inhibition of its block on the sarcoendoplasmic reticulum calcium ATPase (SERCA). In rat coronary vessels, PKA mediates inhibition of calcium-independent phospholipase A and calcium influx which results in relaxation of the vasculature. This suggests Ucn2 may be beneficial in improving blood but these findings have less biological applicability to human medicine as they were completed on rats. In 2011 a similar relationship was found in human heart. Ucn2 produced a dose dependent relaxation of coronary. This correlation was a result of the cAMP/ PKA pathway and independent of endothelial function. Ucn2 may be a beneficial drug in damaged hearts where the endothelium is not intact.
In the example of lysosomal lipase, the enzyme is confined within an organelle called the lysosome. Other lipase enzymes, such as pancreatic lipases, are secreted into extracellular spaces where they serve to process dietary lipids into more simple forms that can be more easily absorbed and transported throughout the body. Fungi and bacteria may secrete lipases to facilitate nutrient absorption from the external medium (or in examples of pathogenic microbes, to promote invasion of a new host). Certain wasp and bee venoms contain phospholipases that enhance the effects of injury and inflammation delivered by a sting. As biological membranes are integral to living cells and are largely composed of phospholipids, lipases play important roles in cell biology. Malassezia globosa, a fungus thought to be the cause of human dandruff, uses lipase to break down sebum into oleic acid and increase skin cell production, causing dandruff. Genes encoding lipases are even present in certain viruses. Some lipases are expressed and secreted by pathogenic organisms during an infection. In particular, Candida albicans has many lipases, possibly reflecting broad-lipolytic activity, which may contribute to the persistence and virulence of C. albicans in human tissue.
The pia mater (Latin: tender mother) is a very delicate membrane. It is the meningeal envelope that firmly adheres to the surfaces of the brain and spinal cord, following all of the brain's contours (gyri and sulci). It is a very thin sheet of connective tissue that interfaces with the glial limitans superficialis but lacks capillaries itself.
Glycogen synthesis is, unlike its breakdown, endergonic—it requires the input of energy. Energy for glycogen synthesis comes from uridine triphosphate (UTP), which reacts with glucose-1-phosphate, forming UDP-glucose, in a reaction catalysed by UTP—glucose-1-phosphate uridylyltransferase. Glycogen is synthesized from monomers of UDP-glucose initially by the protein glycogenin, which has two tyrosine anchors for the reducing end of glycogen, since glycogenin is a homodimer. After about eight glucose molecules have been added to a tyrosine residue, the enzyme glycogen synthase progressively lengthens the glycogen chain using UDP-glucose, adding α(1→4)-bonded glucose to the nonreducing end of the glycogen chain. The glycogen branching enzyme catalyzes the transfer of a terminal fragment of six or seven glucose residues from a nonreducing end to the C-6 hydroxyl group of a glucose residue deeper into the interior of the glycogen molecule. The branching enzyme can act upon only a branch having at least 11 residues, and the enzyme may transfer to the same glucose chain or adjacent glucose chains.
== Europe == German centenarians receive a letter of congratulations from the president of Germany. In Ireland, centenarians can receive a €2,540 "Centenarians' Bounty" and a letter from the president of Ireland, even if they are resident abroad. Irish people celebrating their 101st birthday may also receive a special silver minted coin with a quote by a famous Irish writer or poet. Centenarians born in Italy receive a letter of congratulations from the president of Italy. In the Netherlands, the monarch and their commissioner sends a letter on the 100th birthday and on every birthday beginning with the 105th. Swedish centenarians receive a telegram from the king and queen of Sweden.
Sources: en.wikipedia.org
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.
It binds to and activates PPARδ, a nuclear receptor that regulates genes related to fatty acid oxidation and energy use. This activation alters transcription in tissues such as skeletal muscle and liver. The full range of downstream effects in humans is not fully established.
No, cardarine is not known to occur naturally in plants, animals, or humans. It is a synthetic molecule produced for laboratory research. Products labeled as cardarine should therefore be treated as manufactured chemicals with variable purity.
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.