Mass spectrometry raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
This page was last updated on 2025-11-23 and is reviewed periodically as new material appears.
Clinical development stopped after rodent studies showed tumors at multiple sites. Whether those findings predict human cancer risk remains an open question, but they led sponsors to discontinue programs. Human safety data are limited to small, short-term studies that were not designed to assess cancer risk. Reported effects in those studies included changes in blood lipids, but the evidence is insufficient for medical use. Long-term consequences of nonmedical use are not well characterized. Questions about dose, duration, and individual susceptibility remain unresolved.
Cardarine is a common name for GW501516, an investigational compound developed in the 1990s for metabolic conditions. It acts as an agonist at peroxisome proliferator-activated receptor delta, a nuclear receptor involved in lipid and energy metabolism. The compound is frequently mislabeled as a selective androgen receptor modulator, or SARM, but its molecular target is different. GW501516 reached early clinical testing before development was discontinued. It has no approved therapeutic use in any country. The name cardarine is not a formal international nonproprietary name.
Regulatory treatment varies, but cardarine is not approved as a medicine. Sports authorities list GW501516 as a prohibited substance, and it is banned at all times under the World Anti-Doping Agency code. Many countries restrict sales for human consumption, while online vendors market it as a research chemical. Such products may lack purity data, and their actual contents can differ from the label. Purchasing or possessing cardarine may carry legal consequences depending on jurisdiction. The compound is not a dietary supplement ingredient in regulated markets.
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 studies indicate that GW501516 activates PPARδ, a nuclear receptor involved in fatty acid oxidation and energy metabolism. In rodent experiments, treated animals often showed increased endurance and reduced fat mass. These effects were observed under controlled conditions and do not establish safe or effective use in humans. The exact dose-response relationship in humans remains poorly characterized. Species differences in metabolism can affect how results translate across animals and people.
| Property | Value | Notes |
|---|---|---|
| Common synonyms | GW501516; GW-1516; endurobol | GW501516 is the research code |
| Drug class | PPARδ agonist | Not a selective androgen receptor modulator |
| Molecular formula | C21H18F3NO3S2 | Established chemical formula |
| Molar mass | 453.5 g/mol | Calculated from the formula |
| Regulatory status | Prohibited in sport; not approved as medicine | Status varies by country |
Laboratory detection of GW501516 commonly uses liquid chromatography coupled with tandem mass spectrometry. The method can identify the parent compound or its metabolites in urine and blood after sample cleanup. Protein precipitation, solid-phase extraction, or enzymatic hydrolysis may precede analysis, depending on the matrix. Reference standards are required for accurate quantification and confirmation. Because the compound is not approved, testing often occurs in anti-doping, forensic, or research settings rather than routine clinical care. Results are reported with limits of detection and quantification.
Stability of GW501516 depends on form, temperature, light exposure, and moisture. Solid reference material is typically stored frozen or refrigerated in a desiccator and protected from light. Solutions in organic solvents such as dimethyl sulfoxide are often kept frozen in aliquots to reduce freeze-thaw cycling. Aqueous solubility is low, so aqueous stock solutions can be difficult to prepare without cosolvents. Degradation may appear as changes in chromatographic purity or mass spectral signal. Stability studies are needed to establish shelf life for any specific preparation.
Regulatory treatment of cardarine differs by context and jurisdiction. In competitive sport, the World Anti-Doping Agency lists PPARδ agonists, including GW501516, as prohibited at all times. Outside sport, it lacks approval as a prescription medicine in major drug markets, and products sold for human consumption may be treated as unapproved drugs. Some countries also restrict importation or sale through general consumer protection and medicines laws. These classifications affect availability, testing, and legal risk without establishing therapeutic value.
Because cardarine is not an approved medicine, no pharmacopeial monograph defines its identity, purity, or storage requirements. Laboratories typically rely on in-house methods and reference standards when testing materials labeled as GW501516. Certificates of analysis may report purity and identity for a specific batch, but their scope varies and they do not guarantee safety or legal status. Independent verification can include high-performance liquid chromatography, mass spectrometry, nuclear magnetic resonance, and elemental analysis. The distinction between research chemical labeling and human use is significant because quality standards and oversight differ.
Cardarine can be detected in biological samples and product materials using liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). The method separates compounds by chromatography and identifies them by mass-to-charge transitions, allowing low-level detection in urine or blood. Sample preparation often involves enzymatic hydrolysis, solid-phase extraction, or protein precipitation. Certified reference materials and isotope-labeled internal standards improve quantification. Detection windows depend on metabolism, matrix, and assay sensitivity, so no single universal window applies.
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.
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.
If a designer is interested only in the best sequence, the protein design algorithm only requires the lowest-energy conformation of the lowest-energy sequence. In these cases, the amino acid identity of each rotamer can be ignored and all rotamers belonging to different amino acids can be treated the same. Let ri be a rotamer at residue position i in the protein chain, and E(ri) the potential energy between the internal atoms of the rotamer. Let E(ri, rj) be the potential energy between ri and rotamer rj at residue position j. Then, we define the optimization problem as one of finding the conformation of minimum energy (ET):
=== Effect of cell cytotoxicity === The enhancement of antitumour immune response by immunomodulators is capable of stimulating reticuloendothelial and T-cell-mediated tumour destruction. The effect of tuftsin on augmentation of cellular cytotoxicity was evaluated both in vitro and in vivo.
Transgenic mice with a fluorescently tagged UBE3A were used to test the effectiveness of unsilencing the paternal copy. When tested on mice in vivo, topotecan affected the hippocampus, striatum and cerebral cortex but not the cerebellum unless a higher dose was administered (21.6 micrograms/hour for five days). The study suggested that the topoisomerase inhibitors have the potential to produce a normally functioning UBE3A protein. Most symptoms due to Angelman syndrome are traditionally treated by speech therapy, physical therapy and occupational therapy. Anti-seizure medication is often prescribed as seizures are a common symptom of Angelman syndrome. These treatments target only symptoms. This drug has been administered to cancer patients. It was well tolerated when administered to pediatric and adult patients.
The true percentage utilization (usually shown with a percent symbol). The percentage utilization relative to a readily utilizable protein source, often egg (usually shown as unitless). The two values will be similar but not identical. The BV of a food varies greatly, and depends on a wide variety of factors. In particular the BV of a food varies depending on its preparation and the recent diet of the organism. This makes reliable determination of BV difficult and of limited use — fasting prior to testing is universally required in order to ascertain reliable figures. BV is commonly used in nutrition science in many mammalian organisms, and is a relevant measure in humans. It is a popular guideline in bodybuilding in protein choice.
Sources: en.wikipedia.org
All lepidosaurs and turtles have a three-chambered heart consisting of two atria, one variably partitioned ventricle, and two aortas that lead to the systemic circulation. The degree of mixing of oxygenated and deoxygenated blood in the three-chambered heart varies depending on the species and physiological state. Under different conditions, deoxygenated blood can be shunted back to the body or oxygenated blood can be shunted back to the lungs. This variation in blood flow has been hypothesized to allow more effective thermoregulation and longer diving times for aquatic species, but has not been shown to be a fitness advantage.
Banting was appointed Senior Demonstrator in Medicine at the University of Toronto in 1922. Next year he was elected to the new Banting and Best Chair of Medical Research, endowed by the Legislature of the province of Ontario. He also served as Honorary Consulting Physician to the Toronto General, the Hospital for Sick Children, and the Toronto Western Hospital. At the Banting and Best Institute, he focused his research on silicosis, cancer, and the mechanisms of drowning. In 1938, Banting's interest in aviation medicine resulted in his participation with the Royal Canadian Air Force (RCAF) in research concerning the physiological problems encountered by pilots operating high-altitude combat aircraft. Banting headed the RCAF's Number 1 Clinical Investigation Unit (CIU), which was housed in a secret facility on the grounds of the former Eglinton Hunt Club in Toronto. During the Second World War he investigated the problems of aviators, such as "blackout" (syncope). He also helped Wilbur Franks with the invention of the G-suit to stop pilots from blacking out when they were subjected to g-forces while turning or diving. Another of Banting's projects during the Second World War involved using and treating mustard gas burns. Banting even tested the gas and antidotes on himself to see if they were effective.
Following a Round 22 61-point demolition at the hands of lower-placed Hawthorn, Thompson's job was under immense pressure. After a very public review of the club, it was decided that Thompson should keep his job as senior coach. After a shaky start to the 2007 season that led many supporters to believe that nothing had changed from the 2006 season, Thompson led Geelong to a massive 15 match winning streak (the biggest in a single season in club history) and a 106-point win against the Kangaroos in the Qualifying Final which is the 5th biggest finals winning margin in AFL/VFL history. The 2007 season then culminated in one of the biggest, if not the best highlight of Thompson's career, in both a coaching and footballer's role. Thompson coached Geelong to win the AFL premiership in the 2007 AFL Grand Final by more than 100 points, which was the highest winning margin in Grand Final history, against Port Adelaide Football Club at the MCG on 29 September. It was the club's first premiership since 1963, the year of Thompson's birth. After the Essendon Football Club decided not to give Thompson's former mentor, Kevin Sheedy, a renewal of contract, there was speculation that Mark Thompson would take up the senior coaching role at Essendon for the 2008 season. However, with trade week quickly approaching, the club instead appointed Matthew Knights to the position. After Geelong's record-breaking win in the grand final, Geelong under Thompson were red hot favourite to repeat their 2007 success in the 2008 season and their form during the year did nothing to change that.
Sources: en.wikipedia.org
The European continental tradition (See: Realism) focused on humans within human-made environments, and included the so-called city symphony films such as Walter Ruttmann's Berlin: Symphony of a Metropolis (of which Grierson noted in an article that Berlin, represented what a documentary should not be); Alberto Cavalcanti's, Rien que les heures; and Dziga Vertov's Man with a Movie Camera. These films tend to feature people as products of their environment, and lean towards the avant-garde.
In the 2010s, Ells tried to diversify the company by creating or acquiring several subsidiaries. These subsidiaries offered very different cuisines compared to their parent company. Examples include soul food (Soul Daddy), Asian cuisine (ShopHouse Southeast Asian Kitchen), pizza (Pizzeria Locale), and burgers (Tasty Made). In 2023, Chipotle had also tried incorporating California-inspired bowls into the Farmesa Fresh Eatery concept. The few test locations were not a financial success, and all concepts were discontinued. In 2011, Steve Ells was a judge for the TV show America's Next Great Restaurant and investor of ANGR Holdings, the company that would launch the winning concept's restaurants. Chipotle agreed to purchase Ells' investment in ANGR at his cost, provide support for ANGR operations, and invest a total of $2.3 million in cash contributions. The winning concept, Soul Daddy, was quickly closed after operating for eight weeks. In September 2011, Chipotle opened an Asian fast-casual concept restaurant named ShopHouse Southeast Asian Kitchen in Washington, D.C. The company said the new restaurant "would follow the Chipotle service format and its focus on 'food with integrity' in ingredients". Chipotle's plan was to start with only one store and see how the restaurant worked out before expanding the concept. On July 29, 2016, the company announced the opening of its first Tasty Made burger restaurant in the fall.
=== Gastrointestinal system === Somatostatin is homologous with cortistatin (see somatostatin family) and suppresses the release of gastrointestinal hormones Decreases the rate of gastric emptying, and reduces smooth muscle contractions and blood flow within the intestine Inhibits adenylyl cyclase in parietal cells, thereby suppressing gastric acid secretion Suppresses the release of pancreatic hormones Somatostatin release is triggered by the beta cell peptide urocortin3 (Ucn3) to inhibit insulin release. Inhibits the release of glucagon Suppresses the exocrine secretory action of the pancreas
Dr (Heinz) Wuschech knows more about anabolic steroids than any doctor I have ever met, and yet he cannot discuss them openly any more than Geoff Capes or Mac Wilkins can openly discuss them in the current climate of amateur sports regulation. What I did learn in East Germany was that they feel there is little danger from anabolica, as they call it, when the athletes are kept on strictly monitored programmes. Although the extremely dangerous side-effects are admitted, they are statistically no more likely to occur than side-effects from the birth control pill. If, that is, programmes are constantly medically monitored as to dosage. Other reports came from the occasional athlete who fled to the West – 15 of them between 1976 and 1979. One, the ski-jumper Hans-Georg Aschenbach, said: "Long-distance skiers start having injections to their knees from the age 14 because of their intensive training." He said: "For every Olympic champion, there are at least 350 invalids. There are gymnasts among the girls who have to wear corsets from the age of 18 because their spine and their ligaments have become so worn... There are young people so worn out by the intensive training that they come out of it mentally blank [lessivés – washed out], which is even more painful than a deformed spine." After the 1990 German reunification, on 26 August 1993 the records were opened and evidence found that the Stasi, the state secret police, supervised systematic doping of East German athletes from 1971 until reunification in 1990.
Sources: en.wikipedia.org
No. Cardarine is GW501516, a PPARδ agonist, while SARMs act on androgen receptors. The two classes are often grouped in informal discussions despite different mechanisms.
No. It has no approved medical indication in any country. Regulatory agencies have not cleared it for treatment or prevention of any condition.
Early clinical work stopped after rodent carcinogenicity findings. Those animal results raised concerns about long-term human risk, although direct human evidence is lacking. The human relevance of the tumors remains an open scientific question.
Rodent studies reported increased endurance and fat oxidation after GW501516 exposure. Long-term studies also found higher rates of some tumors, which led to halted development.