If you have been reading about anti-doping and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Updated 2026-01-16. Numbers and descriptions here follow the published literature rather than marketing material.
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.
PPARδ is a nuclear receptor that influences transcription of genes involved in fatty acid oxidation, lipid transport, and energy homeostasis. GW501516 binds and activates this receptor with high selectivity relative to PPARα and PPARγ in laboratory assays. Activation alters expression of target genes in skeletal muscle, liver, and adipose tissue in animal models. The exact clinical consequences of these changes in humans remain incompletely characterized, and observed effects in animals do not establish therapeutic benefit or safety.
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.
| Property | Value | Notes |
|---|---|---|
| Regulatory status | Prohibited in sport; not approved as medicine | Listed by WADA at all times. |
| Common synonyms | GW501516, GW-501516, endurobol | Cardarine is a colloquial name. |
| Typical analytical method | LC-MS/MS | Detects parent compound and metabolites. |
| Common test matrix | Urine | Blood and dried blood spots also possible. |
| Legal classification | Varies by country | Often treated as unapproved drug or research chemical. |
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.
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.
Researchers in biochemistry use specific techniques native to biochemistry (for instance, enzyme kinetics or subcellular fractionation), but increasingly combine these with techniques and ideas developed in the fields of genetics, molecular biology, and biophysics. There is not a defined line between these disciplines. Biochemistry studies the chemistry required for biological activity of molecules, molecular biology studies those molecules' biological activity, and genetics studies their heredity, which happens to be carried by their genome. This is shown in the following schematic that depicts one possible view of the relationships between the fields:
In mammals, the genome only contains one gene for tropoelastin, called ELN. The human ELN gene is a 45 kb segment on chromosome 7, and has 34 exons interrupted by almost 700 introns, with the first exon being a signal peptide assigning its extracellular localization. The large number of introns suggests that genetic recombination may contribute to the instability of the gene, leading to diseases such as SVAS. The expression of tropoelastin mRNA is highly regulated under at least eight different transcription start sites. Tissue specific variants of elastin are produced by alternative splicing of the tropoelastin gene. There are at least 11 known human tropoelastin isoforms. These isoforms are under developmental regulation, however there are minimal differences among tissues at the same developmental stage.
Nanocomposites are desirable for their mechanical properties. When fillers in a composite are at the nanometer length scale, the surface to volume ratio of the filler material is high, which influences the bulk properties of the composite more compared to traditional composites. The properties of these nanosized elements is markedly different from that of its bulk constituent. In regards to natural fibers, some of the best example of nanocomposites appear in biology. Bone, abalone shell, nacre, and tooth enamel are all nanocomposites. As of 2010, most synthetic polymer nanocomposites exhibit inferior toughness and mechanical properties compared to biological nanocomposites. Completely synthetic nanocomposites do exist, however nanosized biopolymers are also being tested in synthetic matrices. Several types of protein based, nanosized fibers are being used in nanocomposites. These include collagen, cellulose, chitin and tunican. These structural proteins must be processed before use in composites. To use cellulose as an example, semicrystalline microfibrils are sheared in the amorphous region, resulting in microcrystalline cellulose (MCC). These small, crystalline cellulose fibrils are at this points reclassified as a whisker and can be 2 to 20 nm in diameter with shapes ranging from spherical to cylindrical. Whiskers of collagen, chitin, and cellulose have all been used to make biological nanocomposites. The matrix of these composites are commonly hydrophobic synthetic polymers such as polyethylene, and polyvinyl chloride and copolymers of polystyrene and polyacrylate.
Initially, there was a misconception that due to its predominantly water-based composition, cartilage had a Poisson's ratio of 0.5 and should be modeled as an incompressible material. However, subsequent research has disproven this belief. The Poisson's ratio of articular cartilage has been measured to be around 0.4 or lower in humans and ranges from 0.46–0.5 in bovine subjects. The mechanical properties of articular cartilage are largely anisotropic, test-dependent, and can be age-dependent. These properties also depend on collagen-proteoglycan interactions and therefore can increase/decrease depending on the total content of water, collagen, glycoproteins, etc. For example, increased glucosaminoglycan content leads to an increase in compressive stiffness, and increased water content leads to a lower aggregate modulus.
Sources: en.wikipedia.org
== Natural alpha glucosidase inhibitors == There are a large number of natural products with alpha-glucosidase inhibitor action. In fact, the prototypic drug of this class (acarbose) is discovered from soil bacteria. For example, research has shown the culinary mushroom Maitake (Grifola frondosa) has a hypoglycemic effect. The reason Maitake lowers blood sugar is because the mushroom naturally contains an alpha glucosidase inhibitor. All cinnamon species show acarbose-like activity. A single dose of raw cinnamon before a meal containing complex carbohydrates decreases the postprandial hyperglycemia (higher than 140 mg/dL; >7.8 mmol/L) in patients with type II diabetes. Another plant attracting a lot of attention is Salacia oblonga.
== Role in disease == High levels of kynurenic acid have been identified in patients with tick-borne encephalitis, schizophrenia and HIV-related illnesses. In all these situations, increased levels were associated with confusion and psychotic symptoms. Kynurenic acid acts in the brain as a glycine-site NMDAr antagonist, key in glutamatergic neurotransmission system, which is thought to be involved in the pathophysiology and pathogenesis of schizophrenia. The kynurenic acid hypothesis of schizophrenia was proposed in 2007, based on its action on midbrain dopamine activity and NMDArs, thus linking dopamine hypothesis of schizophrenia with the glutamate hypothesis of the disease. Kynurenic acid is reduced in individuals with mood disorders, such as major depressive disorder and bipolar disorder, especially during depressive episodes. High levels of kynurenic acid have been identified in human urine in certain metabolic disorders, such as marked pyridoxine deficiency and deficiency/absence of kynureninase. When researchers decreased the levels of kynurenic acid in the brains of mice, their cognition was shown to improve markedly. However, kynurenic acid also shows neuroprotective properties. Some researchers have posited that the increased levels found in cases of neurological degradation is due to a failed attempt to protect the cells.
Light irradiance and wavelength Water absorption Carbon dioxide concentration Temperature. Total photosynthesis is limited by a range of environmental factors. These include the amount of light available, the amount of leaf area a plant has to capture light (shading by other plants is a major limitation of photosynthesis), the rate at which carbon dioxide can be supplied to the chloroplasts to support photosynthesis, the availability of water, and the availability of suitable temperatures for carrying out photosynthesis.
North American box turtles breathe continuously during locomotion, and the ventilation cycle is not coordinated with the limb movements. This is because they use their abdominal muscles to breathe during locomotion. The last species to have been studied is the red-eared slider, which also breathes during locomotion, but takes smaller breaths during locomotion than during small pauses between locomotor bouts, indicating that there may be mechanical interference between the limb movements and the breathing apparatus. Box turtles have also been observed to breathe while completely sealed up inside their shells.
== Mechanism == Pulsatile insulin secretion from individual beta cells is driven by oscillation of the calcium concentration in the cells. In beta cells lacking contact, the periodicity of these oscillations is rather variable (2-10 min). However, within an islet of Langerhans the oscillations become synchronized by electrical coupling between closely located beta cells that are connected by gap junctions, and the periodicity is more uniform (3-6 min).
Sources: en.wikipedia.org
Some studies report increased depressive symptoms and anxiety, potentially linked to the sensitization of the hypothalamic-pituitary-adrenal (HPA) axis and elevated cortisol levels. Others find no association or even reduced symptoms. Copper IUDs confer an increased risk of longer, heavier, and/or more painful menstrual periods.
=== Nephrogenesis === One example of this, the most well described of the developmental METs, is kidney ontogenesis. The mammalian kidney is primarily formed by two early structures: the ureteric bud and the nephrogenic mesenchyme, which form the collecting duct and nephrons respectively (see kidney development for more details). During kidney ontogenesis, a reciprocal induction of the ureteric bud epithelium and nephrogenic mesenchyme occurs. As the ureteric bud grows out of the Wolffian duct, the nephrogenic mesenchyme induces the ureteric bud to branch. Concurrently, the ureteric bud induces the nephrogenic mesenchyme to condense around the bud and undergo MET to form the renal epithelium, which ultimately forms the nephron. Growth factors, integrins, cell adhesion molecules, and protooncogenes, such as c-ret, c-ros, and c-met, mediate the reciprocal induction in metanephrons and consequent MET.
White Paper on Full Employment in Australia (1945) – defined economic policy for 30 years Reserve Bank Act 1959 s 10 NAIRU reporting Fiscal policy Full employment and industrial policy Unemployment insurance Workforce Australia, Employment Services Act 1994
=== Antibiotics === Physicians often prescribe the antibiotic trimethoprim-sulfamethoxazole to prevent bacterial infections. This drug also has the benefit of sparing the normal bacteria of the digestive tract. Fungal infection is commonly prevented with itraconazole, although a newer drug of the same type called voriconazole may be more effective. The use of this drug for this purpose is still under scientific investigation.
Action Half-Life is a mod for the first-person shooter video game Half-Life. It strives to simulate action movies, especially those directed by John Woo. Action Half-Life is the second mod in the "Action" series. The first was Action Quake 2 and the third was Action Unreal Tournament 2004.
Sources: en.wikipedia.org
Legal status varies by country. It is not approved as a medicine, and it is prohibited in sport. Some jurisdictions restrict import, sale, or possession.
Laboratories use liquid chromatography-tandem mass spectrometry to detect GW501516 and its metabolites. Urine is commonly tested, and testing can occur in and out of competition.
No, cardarine is not a SARM. It is a PPARδ agonist, which acts on a different receptor. The two classes are often confused in online discussions.
Cardarine is commonly known as GW501516 or GW-1516. These names refer to the same synthetic compound. It is not a brand-name approved medicine.