A practical reference on GW501516: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
Reviewed 2026-01-17. Anything still debated is marked as such rather than presented as settled.
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.
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.
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.
| 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. |
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.
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.
Sporting authorities added GW501516 to prohibited lists after it appeared in athlete samples and online markets. The World Anti-Doping Agency classifies it as a hormone and metabolic modulator, and its use can lead to an anti-doping rule violation. Some early laboratory work suggested effects on fatty acid oxidation and endurance-related metabolism in animals, but those findings do not establish safe or effective use in people. Reports of adverse events in humans are scarce and often anecdotal, which complicates risk assessment.
Legal status varies by country. In some places, cardarine is controlled under medicines or psychoactive substances laws; in others, it may be sold with minimal oversight as a research chemical. Customs agencies have intercepted shipments, and several national health agencies have issued warnings about products marketed for bodybuilding or performance enhancement. The lack of a standardized pharmaceutical supply means identity, purity, and contamination levels can differ widely between samples. These factors make cardarine a regulatory and public health concern rather than a conventional prescription drug.
Cardarine is a synthetic compound also known as GW501516, GW-501516, and sometimes endurobol. It was developed as a selective agonist of peroxisome proliferator-activated receptor delta, a nuclear receptor involved in fatty acid oxidation and energy metabolism. The compound was studied in preclinical models for metabolic and cardiovascular conditions, but it did not become a marketed human medicine. In regulatory and anti-doping contexts, it is treated as a prohibited substance rather than a licensed medicine.
The pharmacological interest in cardarine centers on PPARδ activation and its downstream effects on lipid handling and mitochondrial function. In animal studies, PPARδ agonists have been associated with changes in exercise endurance and fatty acid utilization, though results vary by model and protocol. Human data remain sparse, and the absence of large controlled trials limits conclusions about efficacy. Researchers often describe the compound as a tool for probing PPARδ biology rather than a proven therapeutic agent.
Safety discussions about cardarine frequently cite rodent carcinogenicity findings reported in the 2000s. In those studies, treated animals developed tumors at multiple sites, leading sponsors to discontinue clinical development. The relevance of these findings to humans has not been resolved, but they are a major reason the compound is not approved. Current literature emphasizes uncertainty about long-term effects and the risks of unregulated use. Regulators and health agencies have not established a safe human exposure level.
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.
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.
=== TV documentaries === ARTE (French/German TV Channel): Since 2018, ARTE has aired documentaries on the world of fascia, featuring Robert Schleip. SWR (German TV Channel): Documentaries aired on October 25, 2021, and September 10, 2020, explored the "fascia boom" and included contributions from Schleip.
As is typical of the symptoms associated with psilocybin mushroom ingestion, "the effect on mood in particular is dependent on the subject's pre-exposure personality traits", and "identical doses of psilocybin may have widely differing effects in different individuals." Although most cases of intoxication resolve without incident, there have been isolated cases with severe consequences, especially after higher dosages or persistent use. In one case reported in Poland in 1998, an 18-year-old man developed Wolff–Parkinson–White syndrome, arrhythmia, and suffered myocardial infarction after ingesting P. semilanceata frequently over the period of a month. The cardiac damage and myocardial infarction was suggested to be a result of either coronary vasoconstriction, or because of platelet mediated occlusion of small coronary arteries.
=== In Vivo Translation Tracking === The techniques above require lysis of cells and thus cannot be performed in living cells. Single-molecule fluorescence resonance energy transfer (smFRET) and Nascent chain tracking (NCT) use fluorescence to track translational activity. Both methods track elongation rates of the polypeptides on single mRNAs. Neither technique, however, is capable of high throughput.
Sources: en.wikipedia.org
=== Three-dimensional chain codes === The E. coli lactose operon repressor LacI (PDB: 1lcc chain A) and E. coli catabolite gene activator (PDB: 3gap chain A) both have a helix-turn-helix motif, but their amino acid sequences do not show much similarity, as shown in the table below. In 1997, Matsuda, et al. devised a code they called the "three-dimensional chain code" for representing the protein structure as a string of letters. This encoding scheme reveals the similarity between the proteins much more clearly than the amino acid sequence (example from article): The code encodes the torsion angles between alpha-carbons of the protein backbone. "W" always corresponds to an alpha helix.
The extent to which psilocin (and by extension psilocybin) is metabolized by MAO, specifically MAO-A, is not fully clear, but has ranged from 4% to 33% in different studies based on metabolite excretion. However, circulating levels of the deaminated metabolite of psilocin are far higher than those of free unmetabolized psilocin with psilocybin administration. An early clinical study of psilocybin in combination with short-term tranylcypromine pretreatment found that tranylcypromine marginally potentiated the peripheral effects of psilocybin, including pressor effects and mydriasis, but overall did not significantly modify the psychoactive and hallucinogenic effects of the psilocybin, although some of its emotional effects were said to be reduced and some of its perceptual effects were said to be amplified. Some psychedelics are substrates of cytochrome P450 (CYP450) enzymes, for instance LSD being a substrate of CYP2D6 as well as of several other CYP450 enzymes. As such, CYP450 inhibitors may increase exposure to CYP450-substrate psychedelics such as LSD and thereby potentiate their effects as well as risks. A clinical study found that administration of LSD to people taking paroxetine, a selective serotonin reuptake inhibitor (SSRI) and strong CYP2D6 inhibitor, increased LSD exposure by about 1.5-fold. The combination was well-tolerated and did not modify the pleasant subjective effects or physiological effects of LSD, whereas negative effects of LSD, including "bad drug effect", anxiety, and nausea, were reduced.
E3 enzymes possess one of two domains: the homologous to the E6-AP carboxyl terminus (HECT) domain and the really interesting new gene (RING) domain (or the closely related U-box domain). HECT domain E3s transiently bind ubiquitin in this process (an obligate thioester intermediate is formed with the active-site cysteine of the E3), whereas RING domain E3s catalyse the direct transfer from the E2 enzyme to the substrate. The anaphase-promoting complex (APC) and the SCF complex (for Skp1-Cullin-F-box protein complex) are two examples of multi-subunit E3s involved in recognition and ubiquitylation of specific target proteins for degradation by the proteasome. In the ubiquitylation cascade, E1 can bind with many E2s, which can bind with hundreds of E3s in a hierarchical way. Having levels within the cascade allows tight regulation of the ubiquitylation machinery. Other ubiquitin-like proteins (UBLs) are also modified via the E1–E2–E3 cascade, although variations in these systems do exist. E4 enzymes, or ubiquitin-chain elongation factors, are capable of adding pre-formed polyubiquitin chains to substrate proteins. For example, multiple monoubiquitylation of the tumor suppressor p53 by Mdm2 can be followed by addition of a polyubiquitin chain using p300 and CBP. Some proteins contain extended lysine-free regions, known as lysine deserts, which have been studied as features that may limit lysine-directed ubiquitination while still allowing other forms of ubiquitin-dependent regulation.
Sources: en.wikipedia.org
inorganic ions (typically monitored as electrical conductivity or resistivity or specific tests) organic compounds (typically monitored as TOC or by specific tests) bacteria (monitored by total viable counts or epifluorescence) endotoxins and nucleases (monitored by LAL or specific enzyme tests) particulates (typically controlled by filtration) gases (typically managed by degassing when required)
This intracellular screening technique allows for the discovery of ligands that engage targets in their native conformation and cellular environment, enabling screening of targets that are difficult to express or purify, and potentially improving the physiological relevance of identified compounds.
Tropical bats tend to be homoeothermic (having a stable body temperature), while temperate and subtropical species which enter hibernation or torpor are more heterothermic (where body temperature can vary). Compared to other mammals, bats have a high thermal conductivity. They lose heat via the wings when they are spread, so resting bats wrap their wings around themselves to keep warm. Smaller bats generally have a higher metabolic rate than larger bats and so need to consume more food in order to maintain homoeothermy. Bats may avoid flying during the day to prevent overheating in the sun, since they would absorb sun radiation via their dark wing membranes. Bats may not be able to release heat if the ambient temperature is too high; they use saliva to cool themselves in extreme conditions. Among megabats, the flying fox Pteropus hypomelanus uses saliva and wing-fanning to cool itself while roosting during the hottest part of the day. Among microbats, the Yuma myotis (Myotis yumanensis), the Mexican free-tailed bat (Tadarida brasiliensis), and the pallid bat (Antrozous pallidus) cope with temperatures up to 45 °C (113 °F) by panting, salivating, and licking their fur to promote evaporative cooling; this is sufficient to release twice their metabolic heat production.
== Interaction with integrin α2β1 == Cellular receptors for collagens belong to the family of β1 integrins. Collagen XXIII interacts in an ion-and conformation-dependent manner with integrin α2β1. Integrin α2β1 is a collagen-binding integrin present at the epidermis, therefore this is the location where the interaction takes place. Both proteins co-localize on basal keratinocytes surface.
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 a common name for GW501516, a synthetic PPARδ agonist developed for research. It has not been approved as a medication in any country. It is classified as an unapproved drug and a prohibited substance in sport.