This is a working overview of LC-MS/MS, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2025-08-22 and is reviewed periodically as new material appears.
Handling and quality assessment of cardarine reference material follow general laboratory practices for poorly characterized compounds. It typically appears as a white to off-white powder and is sparingly soluble in water but soluble in organic solvents such as dimethyl sulfoxide and ethanol. Storage recommendations usually specify a cool, dry, dark place, with long-term storage at low temperature and desiccation. Purity may be checked by high-performance liquid chromatography with ultraviolet detection, while identity is confirmed by mass spectrometry and nuclear magnetic resonance. No pharmacopeial monograph exists, so reported purity and stability depend on the supplier’s 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.
Analytical laboratories typically identify cardarine and its metabolites using liquid chromatography-tandem mass spectrometry. Urine is a common matrix in anti-doping testing, while blood and tissue may be used in research settings. Detection windows depend on the assay, the sample matrix, and the compound's metabolism. Because cardarine is extensively metabolized, laboratories often target specific metabolites to improve sensitivity and confirmation. Reference standards are required for reliable quantification. Method validation includes checks for selectivity, linearity, and carryover.
A persistent misconception is that cardarine is a fat-burning drug or a safe alternative to anabolic steroids. No approved therapeutic product exists, and human safety data are limited. The tumor findings in rodents remain a central concern in scientific reviews. Products sold online may contain inaccurate labels, impurities, or different compounds entirely, which complicates any assessment of effects. Independent testing of such products has reported frequent mislabeling. For these reasons, discussions in the literature emphasize risks and unknowns rather than benefits.
Cardarine is not approved for human therapeutic use in any major jurisdiction. It appears on the World Anti-Doping Agency Prohibited List as a PPARδ agonist within the hormone and metabolic modulators category. Sports organizations test for it because it has been detected in athlete samples and seized products. Regulatory actions against marketed research chemical versions have occurred in several countries, though enforcement varies. Availability through unregulated channels complicates oversight.
| Property | Value | Notes |
|---|---|---|
| Appearance | White to off-white powder | Visual description for typical solid reference material. |
| Solubility | Poorly soluble in water; soluble in DMSO | Solubility depends on solvent, purity, and form. |
| Storage | Cool, dry, protected from light | Long-term storage often uses low temperature and desiccant. |
| Common analytical method | LC-MS/MS | Used for detection and quantification in biological matrices. |
| Common synonyms | GW-501516; GW501516; endurobol | Naming varies among literature, vendors, and databases. |
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.
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.
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.
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.
20 September – Scientists who reported the earliest known interstellar object, CNEOS 2014-01-08, and members of The Galileo Project, report the discovery of an additional candidate interstellar meteor, CNEOS 2017-03-09, in a preprint using the same fireball catalog. They find that the implied material strength of the two objects suggests that interstellar meteors "come from a population with material strength characteristically higher than meteors originating from within the solar system". 21 September – Engineers report the development of autonomous 3D-printing drones for construction and repair. 22 September Nanoengineers report the development of biocompatible microalgae hybrid microrobots for active drug-delivery in the lungs (22 Sep.) and the gastrointestinal tract (GT) (28 Sep.). The microrobots are related to medical nanobots and proved effective in tests with mice. A separate team reports the development of 'RoboCap', a robotic drug delivery capsule that enhances drug absorption by tunneling through the mucus layer in the GT (28 Sep.). Around September, news outlets report about deployment, research and development of novel military drone technology in the Russo-Ukrainian War in 2022, including demining drones, self-repurposed commercial/hobby drones (including via a hackathon), reconnaissance microdrones, kamikaze drones, bomb-dropping modified drones, and countermeasures such as electronic ones.
Therefore, the development of devices facilitating the transition from samples at higher pressure and in condensed phase (solid or liquid) into a vacuum system has been essential to develop MS as a potent tool for identification and quantification of organic compounds like peptides. MS is now in very common use in analytical laboratories that study physical, chemical, or biological properties of a great variety of compounds. Among the many different kinds of mass analyzers, the ones that find application in LC–MS systems are the quadrupole, time-of-flight (TOF), ion traps, and hybrid quadrupole-TOF (QTOF) analyzers.
== Structure == Lysine carboxypeptidase has a molecular weight of between 270 and 330 kDa (kilodaltons). It is a tetrameric glycoprotein. It is composed of two 83 kDa subunits and two active subunits between 55 kDa and 48 kDa and these are held together by non-covalent interactions. The 83 kDa subunits are regulatory and do not directly contribute to catalytic activity; they are also heavily glycosylated. These function to stabilize the active subunits and keep them in circulation. Catalytic functioning is retained when the 83 kDa subunits are eliminated from the active subunits, but they are still necessary for their support roles. The active subunits are small and relatively unstable at body temperature and blood pH, so they would not last long in the plasma without the regulatory subunits attached. The 55 kDa-48 kDa portions are both catalytically active. The primary structure of the 83 kDa subunit can be split into three main domains. The first domain is located at the N-terminus and consists of 52 amino acids with the first 27 being cysteine-rich. The second domain refers to the next 312 amino acids and it consists of 13 leucine-rich repeat (LRR) sections, each made up of 24 residues. The final C-terminal domain refers to the last 145 residues where amino acids 400-425 hold a cysteine-rich section. The secondary/tertiary structure of the subunit has not yet been experimentally determined, but it has been hypothesized based upon how other LRR proteins fold.
The Br–Br distance is 227 pm (close to the gaseous Br–Br distance of 228 pm) and the Br···Br distance between molecules is 331 pm within a layer and 399 pm between layers (compare the van der Waals radius of bromine, 195 pm). This structure means that bromine is a very poor conductor of electricity, with a conductivity of around 5 × 10−13 Ω−1 cm−1 just below the melting point, although this is higher than the essentially undetectable conductivity of chlorine. At a pressure of 55 GPa (roughly 540,000 times atmospheric pressure) bromine undergoes an insulator-to-metal transition. At 75 GPa it changes to a face-centered orthorhombic structure. At 100 GPa it changes to a body centered orthorhombic monatomic form.
Sources: en.wikipedia.org
Undernutrition weakens every part of the immune system. Protein and energy undernutrition increases susceptibility to infection; so do deficiencies of specific micronutrients (including iron, zinc, and vitamins). In communities or areas that lack access to safe drinking water, these additional health risks present a critical problem. Undernutrition plays a major role in the onset of active tuberculosis. It also raises the risk of HIV transmission from mother to child, and increases replication of the virus. Undernutrition can cause vitamin-deficiency-related diseases like scurvy and rickets. As undernutrition worsens, those affected have less energy and experience impairment in brain functions. Undernutrition can also cause acute problems, like hypoglycemia (low blood sugar). This condition can cause lethargy, limpness, seizures, and loss of consciousness. Children are particularly at risk and can become hypoglycemic after 4 to 6 hours without food. Dehydration can also occur in malnourished people, and can be life-threatening, especially in babies and small children.
The Raoulii were descended from an Italo-Norman named Raoul, the Petraliphae were descended from a Pierre d'Aulps, and that group of Albanian clans known as the Maniakates were descended from Normans who served under George Maniaces in the Sicilian expedition of 1038. Robert Guiscard, another Norman adventurer previously elevated to the dignity of count of Apulia as the result of his military successes, ultimately drove the Byzantines out of southern Italy. Having obtained the consent of Pope Gregory VII and acting as his vassal, Robert continued his campaign conquering the Balkan peninsula as a foothold for western feudal lords and the Catholic Church. After allying himself with Croatia and the Catholic cities of Dalmatia, in 1081 he led an army of 30,000 men in 300 ships landing on the southern shores of Albania, capturing Valona, Kanina, Jericho (Orikumi), and reaching Butrint after numerous pillages. They joined the fleet that had previously conquered Corfu and attacked Dyrrachium from land and sea, devastating everything along the way. Under these harsh circumstances, the locals accepted the call of Emperor Alexios I Comnenos to join forces with the Byzantines against the Normans. The Byzantine forces could not take part in the ensuing battle because it had started before their arrival. Immediately before the battle, the Venetian fleet had secured a victory in the coast surrounding the city.
In molecular biology the MAPEG (Membrane-Associated Proteins in Eicosanoid and Glutathione metabolism) family of proteins are a group of membrane associated proteins with highly divergent functions. Included are the 5-lipoxygenase-activating protein (gene FLAP), leukotriene C4 synthase (EC 2.5.1.37), which catalyzes the production of leukotriene C4 (LTC4) from leukotriene A4 (LTA4), and microsomal glutathione S-transferase II (EC 2.5.1.18) (GST-II), which also produces LTC4 from LTA4. Another example is prostaglandin E synthase. This enzyme catalyses the synthesis of PGE2 from PGH2 (produced by cyclooxygenase from arachidonic acid). Because of structural similarities in the active sites of FLAP, LTC4 synthase, and PGE synthase, substrates for each enzyme can compete with one another and modulate synthetic activity.
Nausea and vomiting are two of the most feared cancer treatment-related side-effects for people with cancer and their families. In 1983, Coates et al. found that people receiving chemotherapy ranked nausea and vomiting as the first and second most severe side-effects, respectively. Up to 20% of people receiving highly emetogenic agents in this era postponed, or even refused potentially curative treatments. Chemotherapy-induced nausea and vomiting (CINV) are common with many treatments and some forms of cancer. Since the 1990s, several novel classes of antiemetics have been developed and commercialized, becoming a nearly universal standard in chemotherapy regimens, and helping to successfully manage these symptoms in many people. Effective mediation of these unpleasant and sometimes debilitating symptoms results in increased quality of life for the recipient and more efficient treatment cycles, as patients are less likely to avoid or refuse treatment.
== Mechanisms == VIP binds to both VPAC1 and VPAC2 receptors. When VIP binds to VPAC2 receptors, a G-alpha-mediated signaling cascade is triggered. In a number of systems, VIP binding activates adenyl cyclase activity leading to increases in cAMP concentration and PKA activity. The PKA then activates other intracellular signaling pathways like the phosphorylation of CREB and other transcriptional factors. The mPer1 and mPer2 promoters have CRE domains and thus provides the mechanism for VIP to regulate the molecular clock itself. Then it will activate gene expression pathways such as Per1 and Per2 in circadian rhythm. In addition, GABA levels are connected to VIP in that they are co-released. Sparse GABAergic connections are thought to decrease synchronized firing. While GABA controls the amplitude of SCN neuronal rhythms, it is not critical for maintaining synchrony. However, if GABA release is dynamic, it may mask or amplify synchronizing effects of VIP inappropriately. Circadian time is likely to affect the synapses rather than the organization of VIP circuits.
Sources: en.wikipedia.org
Cardarine targets PPARδ, a nuclear receptor involved in lipid and energy metabolism. It does not bind the androgen receptor in the way SARMs do.
Most methods use liquid chromatography with tandem mass spectrometry. Urine is common in anti-doping testing, and blood or plasma may be used in research.
Typical guidance is cool, dry, dark storage, often at low temperature and with desiccant. Stability data are limited, so storage conditions should be verified for each batch or supplier.
No. Cardarine has not received approval for human therapeutic use in major jurisdictions. It remains an investigational compound.