If you have been reading about Mass spectrometry 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 2025-07-29. Numbers and descriptions here follow the published literature rather than marketing material.
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.
Quality assessment for cardarine samples usually combines identity, purity, and impurity testing. Nuclear magnetic resonance spectroscopy and mass spectrometry can confirm molecular structure, while high-performance liquid chromatography estimates purity. Certificates of analysis from testing laboratories may list these results, but they do not establish safety or legality. In the absence of approved manufacturing, products sold online may contain the wrong compound, variable amounts, or unlisted contaminants. Independent verification is therefore central to analytical work and to interpreting any reported biological activity.
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 | Common for reference-grade material. |
| Solubility | Low in water | Dissolves in DMSO and some organic solvents. |
| Typical storage | -20 °C, desiccated | Protect from light and moisture. |
| Analytical method | LC-MS/MS | Used for trace detection in biological matrices. |
| Purity assessment | HPLC with UV detection | Often combined with NMR and mass spectrometry. |
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.
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.
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.
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.
=== Ruminants === Cattle that consume bracken ferns develop acute bracken poisoning and chronic bovine enzootic haematuria (BEH). The main feature of acute bracken poisoning in cattle is the depression of bone marrow activity, which gives rise to severe leucopenia (particularly of the granulocytes), thrombocytopenia, and acute haemorrhagic crisis. However, most of the researchers believe ptaquiloside is not the direct causing agent of the acute bracken fern poisoning. The main feature of haematuria is urinary bladder tumors and haematuria in cattle after prolonged exposure to bracken. Based on the extensive studies, a positive correlation is shown between the ptquiloside concentration and the incidence of BEH.
α-ketoglutarate + NH+4 ⇄ glutamate The α-ketoglutarate family of amino acid synthesis (synthesis of glutamate, glutamine, proline and arginine) begins with α-ketoglutarate, an intermediate in the Citric Acid Cycle. The concentration of α-ketoglutarate is dependent on the activity and metabolism within the cell along with the regulation of enzymatic activity. In E. coli citrate synthase, the enzyme involved in the condensation reaction initiating the Citric Acid Cycle is strongly inhibited by α-ketoglutarate feedback inhibition and can be inhibited by DPNH as well high concentrations of ATP. This is one of the initial regulations of the α-ketoglutarate family of amino acid synthesis. The regulation of the synthesis of glutamate from α-ketoglutarate is subject to regulatory control of the Citric Acid Cycle as well as mass action dependent on the concentrations of reactants involved due to the reversible nature of the transamination and glutamate dehydrogenase reactions. The conversion of glutamate to glutamine is regulated by glutamine synthetase (GS) and is a key step in nitrogen metabolism. This enzyme is regulated by at least four different mechanisms: 1. Repression and depression due to nitrogen levels; 2. Activation and inactivation due to enzymatic forms (taut and relaxed); 3. Cumulative feedback inhibition through end product metabolites; and 4. Alterations of the enzyme due to adenylation and deadenylation.
This relation has the correct behavior at extreme values of R∗, as shown by the labeled curve in Figure 3: when R∗ is small, it is consistent with smooth pipe flow, when large, it is consistent with rough pipe flow. However its performance in the transitional domain overestimates the friction factor by a substantial margin. Colebrook acknowledges the discrepancy with Nikuradze's data but argues that his relation is consistent with the measurements on commercial pipes. Indeed, such pipes are very different from those carefully prepared by Nikuradse: their surfaces are characterized by many different roughness heights and random spatial distribution of roughness points, while those of Nikuradse have surfaces with uniform roughness height, with the points extremely closely packed.
Royal Navy hardtack during Queen Victoria's reign was made by machine at the Royal Clarence Victualing Yard at Gosport, Hampshire, stamped with the Queen's mark and the number of the oven in which it was baked. When machinery was introduced into the process, the dough was thoroughly mixed and rolled into sheets about two yards (6 ft; 72 in; 183 cm) long and one yard (3 ft; 36 in; 91 cm) wide, which were then stamped in one stroke into about sixty hexagonal shaped biscuits. The hexagonal shape saved material and time and made them easier to pack compared to the traditional circular shaped biscuit. Hardtack remained an important part of the Royal Navy sailor's diet until the introduction of canned foods; canned meat was first marketed in 1814, and preserved beef in tins was officially introduced to the Royal Navy rations in 1847. As early as the Spanish–American War in 1898, some military hardtack was used by service members in etching or writing notes, often commemorating events or coined with phrases of the time.
== Research and career == In 2007 Delibegovic returned to the United Kingdom, where she was awarded the Research Councils UK 5-year tenure track fellowship to investigate obesity and ageing at the University of Aberdeen. She was made Professor in Diabetes Physiology in 2015 at the age of 38. The field of her research has focussed on the PTP1B phosphatase, the molecular mechanisms that cause diabetes and what the relationship is between diabetes and Alzheimer's disease. She has demonstrated that PTP1B can be used for targeted treatments, reaching the cells of specific organs without causing any side effects. In 2017 Delibegovic demonstrated a novel pharmaceutical, Trodusquemine, that could be used to treat type 2 diabetes and breast cancer. She went on to show that a single dose of Trodusquemine, the PTP1B inhibitor, could be used to reverse the effects of atherosclerosis. During the COVID-19 pandemic, Delibegovic, in collaboration with an SME Vertebrate Antibodies Ltd and the NHS Grampian, obtained funding from the Scottish Government/ Chief Scientist office to develop a diagnostic test that could support mass screening for coronavirus disease. Her long-term aim was to use artificial intelligence to identify which parts of the severe acute respiratory syndrome coronavirus 2 activated the body's immune system. At the time, other coronavirus disease tests available in the United Kingdom would not support rapid deployment, and several were unreliable. In May 2020, the tests developed by Delibegovic and her team were in development.
Sources: en.wikipedia.org
The Hong Kong Rugby Football Union was founded in 1953. Rugby is long established, partly as a result of its being a British colony. Hong Kong Sevens is held annually in Hong Kong and is considered the premier tournament on the World Rugby Sevens Series competition. Hong Kong national rugby union team is ranked 23rd in the world with a peak rating of 21st (2018–2022). Hong Kong is one of the best teams in Asia and has finished first place in the Asia Rugby Championship in 2018, 2019, 2022, 2023, 2024, and 2025. They qualified for the 2027 Rugby World Cup for the first time by winning the 2025 Asia Rugby Championship. The Hong Kong national rugby sevens team is widely regarded as the best rugby sevens team in Asia and a regular participant in the Rugby World Cup Sevens. Hong Kong has won the Asian Sevens Series a record 8 times and the Asian Games 2 times.
=== Diagnostic tests === The initial tests for thalassemias are: Complete blood count (CBC): Checks the number, size, and maturity of blood cells. Hemoglobin of less than 10 g/dl may indicate a carrier, below 7 g/dl is indicative of thalassemia major. In thalassemia major, mean corpuscular volume (MCV) are less than 70 fl, in thalassemia intermedia, MCV levels are below 80 fl (The normal range for MCV is 80–100 fl). The Mentzer index can be a pointer for diagnosis of thalassemia; it can be calculated from a CBC report. Peripheral blood smear: A blood smear examined under a microscope can show red blood cells that are abnormal in shape (poikilocytosis or codocytes), color (hypochromic), or size (microcytic), as well as those with abnormal inclusions (Heinz bodies). Serum iron and ferritin: these tests are needed to rule out iron-deficiency anemia. For an exact diagnosis, the following tests can be performed:
In February 1994 and September 1995, the Wake Shield Facility was carried into orbit by the Space Shuttle. This demonstration platform used the vacuum created in the orbital wake to manufacture thin films of gallium arsenide and aluminum gallium arsenide. On May 31, 2005, the recoverable, uncrewed Foton-M2 laboratory was launched into orbit. Among the experiments were crystal growth and the behavior of molten-metal in weightlessness. The completion of the International Space Station has provided expanded and improved facilities for performing industrial research. NASA and Tethers Unlimited will test the Refabricator aboard the ISS, which is intended to recycle plastic for use in space additive manufacturing. The Material Science Laboratory Electromagnetic Levitator (MSL-EML) on board the Columbus Laboratory is a science facility that can be used to study the melting and solidification properties of various materials. The Fluid Science Laboratory (FSL) is used to study the behavior of liquids in microgravity.
=== Eid al-Fitr ceasefire (19–24 March) === On 18 March, Pakistan and Afghanistan both announced that they would observe a "temporary pause" in hostilities during the Islamic holiday of Eid al-Fitr, on the request of Saudi Arabia, Qatar, and Turkey. Pakistan's information minister said the ceasefire would run from midnight on 19 March to midnight on 24 March. On 19 March, Taliban claimed that despite the ceasefire Pakistan conducted 72 mortar attacks in Kunar province firing 25 artillery shells in Nari District only, and that two civilians were killed in shelling in Nuristan Province. On the Pakistani side meanwhile, a civilian was killed and three wounded in an Afghan mortar attack on Kurram District. On 22 March, Taliban claimed that Pakistani artillery strikes in Kunar killed a person and wounded another, and also claimed that Pakistani forces attacked a vehicle in Paktia province causing no casualties. Pakistani forces killed two TTP insurgents in an attempted attack on an under-construction Police Station in Kurram District. On 23 March, TTP militants kidnapped six people from Orakzai District.
== Biogenesis == The attachment of the heme group is physically separated from the protein biosynthesis. Proteins are synthesized within the cytoplasm and endoplasmic reticulum, while the maturation of cytochromes c occurs in the periplasm of prokaryotes, the intermembrane space of mitochondria or the stroma of chloroplasts. Several biochemical pathways have been discovered that differ depending on organism.
Sources: en.wikipedia.org
LC-MS/MS is common, often after sample cleanup. The assay targets GW501516 or its metabolites.
Reference material is usually kept cold, dry, and protected from light. Frozen aliquots reduce repeated freeze-thaw cycles.
No approved pharmaceutical product exists, so manufacturing and quality controls are not standardized. Products may contain different compounds or impurities.
No. Cardarine has not received approval for human therapeutic use in major jurisdictions. It remains an investigational compound.