If you have been reading about LC-MS/MS 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.
Last reviewed on 2025-11-27. Where a claim depends on a specific study, the study is described rather than over-claimed.
Activation of PPARδ changes transcription of genes involved in fatty acid transport, mitochondrial function, and skeletal muscle fuel preference. In rodent studies, pharmacological PPARδ activation was associated with increased endurance and altered body composition. These findings generated interest in performance enhancement, but species differences and study designs limit direct extrapolation to humans. Small human trials were conducted in the 2000s and later discontinued. The extent to which cardarine produces similar metabolic or performance effects in people remains an open question.
The compound is typically described as a laboratory compound rather than a therapeutic product. Published reports have explored its role in lipid disorders, insulin sensitivity, and exercise metabolism, yet no major drug regulator has approved it for medical use. Commercial samples sold under the cardarine name may vary in purity and identity. Analytical confirmation is therefore necessary when the material is discussed in scientific or regulatory contexts. Its classification as a prohibited substance in sport further shapes how it is studied and reported.
Anti-doping laboratories identify GW501516 and its metabolites using liquid chromatography-tandem mass spectrometry. Urine is the usual matrix, and detection can occur after the parent compound has cleared from blood. The exact detection window depends on dose, formulation, individual metabolism, and assay sensitivity. Because the compound is prohibited at all times, athletes are subject to testing in and out of competition. Analytical methods continue to improve as new metabolites and designer analogs are characterized.
GW501516 acts as a ligand for PPAR delta, a nuclear receptor that regulates transcription of genes involved in fatty acid oxidation and energy use. Activation of this receptor in skeletal muscle shifts metabolism toward fat burning in animal models. The compound does not burn fat directly; it changes gene expression over hours to days. Researchers study it to understand metabolic flexibility and exercise adaptation. Effects observed in rodents are not automatically expected in humans.
Preclinical research reported that GW501516 increased running endurance in mice and improved lipid profiles in some animal species. Early human trials explored effects on high-density lipoprotein cholesterol, triglycerides, and glucose handling, but the program was discontinued. Published human data are sparse and do not establish efficacy for any condition. Studies also examined PPAR delta in cancer biology, with conflicting findings across models. The relationship between receptor activation, tissue context, and disease risk remains an active area of investigation.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic PPARδ agonist | Not a steroid or a selective androgen receptor modulator. |
| Common synonyms | Cardarine, GW501516, GW-501516, endurobol | Names vary by supplier and literature source. |
| Appearance | White to off-white powder | Consistent with many small-molecule research chemicals. |
| Solubility | Low in water; soluble in DMSO and ethanol | Often prepared in organic solvent for laboratory work. |
| Primary target | PPARδ (NR1C2) | Nuclear receptor involved in lipid and energy metabolism. |
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.
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.
In 1944, it was officially decided to abolish the conventional name "Improved Japanese Breed" and call the breeds Japanese Black, Japanese Brown, and Japanese Polled, as the characteristics of each breed had been clarified as a result of improvements. This officially recognized the three crossbreeds as fixed breeds. Then, in 1957, the Japanese Shorthorn was added. They are collectively known as Wagyu. The Uruguay Round of the General Agreement on Tariffs and Trade (GATT) from 1986 to 1994, which set rules for liberalization of international trade, decided to liberalize imports of foreign beef to Japan. Beef imports have been liberalized since 1991. In 1993, beef imports jumped 34% over the previous year, and as a result, Japan's beef self-sufficiency rate dropped below 50%. The liberalization of beef imports has brought about changes in Japan's domestic Wagyu beef production system. In order to compete with cheaper foreign beef, Japanese livestock farmers have become more focused on raising the Japanese Black breed, which has a unique marbling characteristic. As a result, the number of the other three Wagyu breeds has decreased. Following the outbreak of Bovine Spongiform Encephalopathy (BSE) in Japan, the Law for Special Measures Concerning the Management and Relay of Information for Individual Identification of Cattle (Beef Traceability Law) was enacted in 2003. This law stipulates the attachment of ear tags to cattle, the notification, recording, and storage of historical information from birth to beef, and the publication of recorded information on the Internet.
The detection of a surge in release of luteinizing hormone indicates impending ovulation. LH can be detected by urinary ovulation predictor kits (OPK, also LH-kit) that are performed, typically daily, around the time ovulation may be expected. A conversion from a negative to a positive reading would suggest that ovulation is about to occur within 24–48 hours, giving women two days to engage in sexual intercourse or artificial insemination with the intention of conceiving. The recommended testing frequency differs between manufacturers. For example, the Clearblue test is taken daily, and an increased frequency does not decrease the risk of missing an LH surge. On the other hand, the Chinese company Nantong Egens Biotechnology recommends using their test twice per day. If testing once per day, no significant difference has been found between testing LH in the morning versus in the evening, in relation to conception rates, and recommendations of what time in the day to take the test varies between manufacturers and healthcare workers. Tests may be read manually using a color-change paper strip, or digitally with the assistance of reading electronics. Tests for luteinizing hormone may be combined with testing for estradiol in tests such as the Clearblue fertility monitor. The sensitivity of LH tests are measured in milli international unit, with tests commonly available in the range 10–40 m.i.u. (the lower the number, the higher the sensitivity).
== Biodegradability == The biodegradation of PLGA makes it useful for plenty of medical applications with PLGA. For example, a 75:25 lactide to glycolide PLGA ratio can be made as microspheres that degrade via bulk erosion, with polymer composition playing a role in the degradation behavior. This would allow degradation throughout the whole polymer to occur equally. PLGA is also widely used in injectable forms developed to have eroding systems. This form can be used in Lupron Depot. To achieve this, PLGA is dissolved with an organic water-miscible solvent approved by the FDA to create a homogeneous solution or suspension. When injected, the solvent diffuses into the surrounding aqueous environment, causing PLGA to precipitate and form a solid depot. The encapsulated drug is released as the polymer gradually degrades. However, a problem that may occur during the initial injection is that the drug may be released in a quick burst instead of gradually.
Rhizopus oryzae is a filamentous heterothallic microfungus that occurs as a saprotroph in soil, dung, and rotting vegetation. This species is very similar to Rhizopus stolonifer, but it can be distinguished by its smaller sporangia and air-dispersed sporangiospores. It differs from R. oligosporus and R. microsporus by its larger columellae and sporangiospores. The many strains of R. oryzae produce a wide range of enzymes such as carbohydrate digesting enzymes and polymers along with a number of organic acids, ethanol and esters giving it useful properties within the food industries, bio-diesel production, and pharmaceutical industries. It is also an opportunistic pathogen of humans causing mucormycosis.
Aflatoxin B1 and B2 (AFB), produced by A. flavus and A. parasiticus Aflatoxin G1 and G2 (AFG), produced by some Group II A. flavus and Aspergillus parasiticus Aflatoxin M1 (AFM1), metabolite of aflatoxin B1 in humans and animals (exposure in ng levels may come from a mother's milk) Aflatoxin M2, metabolite of aflatoxin B2 in milk of cattle fed on contaminated foods Aflatoxicol (AFL): metabolite produced by breaking down the lactone ring Aflatoxin Q1 (AFQ1), major metabolite of AFB1 in in vitro liver preparations of other higher vertebrates AFM, AFQ, and AFL retain the possibility of becoming an epoxide. Nevertheless, they appear much less capable of causing mutagenesis than the unmetabolized ABM.
Sources: en.wikipedia.org
=== Animals === In cats (and some dogs and ferrets) vaccine-associated sarcoma (VAS) or feline injection-site sarcoma (FISS) occurs at a rate of 1–10 per 10,000 injections. In 1993, a causal relationship between VAS and administration of aluminium-adjuvated rabies and FeLV vaccines was established through epidemiologic methods, and in 1996 the Vaccine-Associated Feline Sarcoma Task Force was formed to address the problem. FISS is characterized by an unintentionally prolonged inflammation at the injection site and an imappropriate respose by the other cells to the inflammation. However, evidence conflicts on whether types of vaccines, manufacturers or factors have been associated with sarcomas. It is unknown why humans do not have this reaction.
X-Ray crystal-structure analysis of plastocyanin at 2.7 Å resolution --- 707 citations Guss, J. M.; Freeman, H. C. (1983). "Structure of oxidised poplar plastocyanin at 1.6 Å resolution". J. Mol. Biol. 169 (2): 521–563. doi:10.1016/S0022-2836(83)80064-3. PMID 6620385. --- 642 citations Guss, J. M.; Harrowell, P. R.; Murata, M.; Norris, V. A.; Freeman, H. C. (1986). "Crystal structure analyses of reduced (CuI) poplar plastocyanin at 6 pH values". J. Mol. Biol. 192 (2): 361–387. doi:10.1016/0022-2836(86)90371-2. PMID 3560221. --- 388 citations Guss, J. M.; Bartunik, H. D.; Freeman, H. C. (1992). "Accuracy and precision in protein-structure analysis: restrained least-squares refinement of the structure of poplar plastocyanin at 1.33 Å resolution". Acta Crystallogr. B. 48 (6): 790–811. Bibcode:1992AcCrB..48..790G. doi:10.1107/S0108768192004270. PMID 1492962. --- 257 citations Kumar, V.; Dooley, D. M.; Freeman, H. C.; Guss, J. M.; Harvey, I.; McGuirl, M. A.; Wilce, M. C. J.; Zubak, V. M. (1996). "Crystal structure of a eukaryotic (pea seedling) copper-containing amine oxidase at 2.2 Å resolution". Structure. 4 (8): 943–955. doi:10.1016/S0969-2126(96)00101-3. PMID 8805580. --- 209 citations
Narrowly most residents included an owner-occupier in their household, with 23.17% of households owning their house outright, and a further 31.33% owning with a mortgage. 10.59% were in local authority housing, with a further 13.29% renting from a housing association, or other registered social landlord. The 2021 census found that the borough has England and Wales's lowest proportion of people born in the UK, at 43.9%. The borough of Brent is extremely ethnically diverse, having changed greatly since 1951. In the 2011 census, those who identified as White British made up 18% of the borough's population. 18% identified as other White, 5% were of mixed heritage, those of South Asian heritage comprised about 33%, those of African and Caribbean heritage about 19%, and other ethnic groups about 7%. White ethnicities were relatively high in the wards of Mapesbury (straddling Willesden Green and Cricklewood), Brondesbury Park, Queen's Park and Kilburn. Black ethnicities in highest proportion were in Stonebridge, Harlesden and Kensal Green wards. Asian ethnicities in highest proportion were in the wards of Alperton, Wembley Central and Kenton. Those who ethnically identify as BAME (Black, Asian and minority Ethnic) was as high as 86% in Wembley Central – one of the highest in London – and most other Brent wards have a majority BAME population. Queen's Park had the lowest BAME proportion, at 37.0%. Brent has the highest proportion of Irish residents in Britain, with 4% of the population.
== Medical uses == Artesunate is the first-line treatment for children or adults with severe malaria, usually in combination with another antimalarial drug. There is moderate-quality evidence that treatment with artesunate plus mefloquine is superior to treatment with artesunate plus amodiaquine or artesunate plus sulfadoxine-pyrimethamine. Artemisinin-based combination therapy may be used by mouth in persons that can tolerate it after 24 hours by injection. Artesunate is preferred over parenteral quinine for severe malaria treatment. Artesunate was shown to prevent more deaths from severe malaria than quinine in two large multicentre randomized controlled trials from Africa and Asia. A subsequent systematic review of seven randomized controlled trials found this improvement in survival rates to be consistent across all trials. Artesunate's efficacy is comparable to that of artemether, another artemisinin derivative, in treating adults for severe malaria caused by Plasmodium falciparum, though artesunate clears more parasites initially. Artesunate combination drugs have a number of advantages over artemether-based drugs in terms of its uptake and administration routes and may be more effective in treatment of severe and complicated malaria in children. Artesunate is also used to treat less-severe forms of malaria when it can be given orally. It has activity against P. ovale, P. malariae, and severe P. knowlesi. Artesunate + sulfadoxine/pyrimethamine for treatment of P. vivax is not recommended due to high rates of resistance.
== See also == 3-Methylbutyrfentanyl 3-Methylfentanyl 4-Fluorobutyrfentanyl 4-Fluoroisobutyrfentanyl α-Methylfentanyl Acetylfentanyl Butyrfentanyl Furanylfentanyl Orthofluorofentanyl List of fentanyl analogues
Sources: en.wikipedia.org
=== Carnivores === Strict carnivores manage vitamin A differently than omnivores and herbivores. Carnivores are more tolerant of high intakes of retinol because those species have the ability to excrete retinol and retinyl esters in urine. Carnivores also have the ability to store more in the liver, due to a higher ratio of liver HSCs to hepatocytes compared to omnivores and herbivores. For humans, liver content can range from 20 to 30 μg/gram wet weight. Notoriously, polar bear liver is acutely toxic to humans because content has been reported in range of 2,215 to 10,400 μg/g wet weight. As noted, in humans, retinol circulates bound to RBP4. Carnivores maintain R-RBP4 within a tight range while also having retinyl esters in circulation. Bound retinol is delivered to cells while the esters are excreted in the urine. In general, carnivore species are poor converters of ionone-containing carotenoids, and pure carnivores such as felidae (cats) lack the cleaving enzyme entirely. They must have retinol or retinyl esters in their diet.
=== Pharmacodynamics === Methaqualone acts primarily as a sedative, reducing anxiety and inducing sleep. It binds to GABAA receptors, where it functions as a positive allosteric modulator at many receptor subtypes, enhancing the inhibitory effects of the neurotransmitter GABA. It shows negligible affinity for a wide array of other potential targets, including other receptors and neurotransmitter transporters. This action is similar to that of benzodiazepines like diazepam. Unlike most benzodiazepines, however, methaqualone may also act as a negative allosteric modulator at certain GABAA receptor subtypes, producing excitatory effects in neurons expressing those receptors. As such, methaqualone is considered a mixed GABAA receptor modulator. The binding site for methaqualone on the GABAA receptor complex is distinct from those of benzodiazepines, barbiturates, and neurosteroids, though it may partially overlap with the etomidate binding site.
=== Endocrine === Hormone levels have been reported in gonadally intact people with CAIS in a number of studies. Hormone levels are similar to those of males, including high testosterone levels and relatively low estradiol levels. However, luteinizing hormone (LH) levels are elevated while sex hormone-binding globulin (SHBG) levels are more consistent with those of females. People with CAIS have low levels of progesterone similarly to males. The production rates of testosterone, estradiol, and estrone have been reported to be higher in gonadally intact with CAIS than in men.
Hydrophilic interaction chromatography (or hydrophilic interaction liquid chromatography, HILIC) is a type of liquid chromatography that uses a hydrophilic stationary phase and a high-organic mobile phase for the separation of analytes by polarity. While it is not as popular as some other types of liquid chromatography, the number of scientific publications using HILIC have greatly increased since the early 2000s. HILIC is similar to reverse phase chromatography in its mobile phase composition, and also to normal phase chromatography, with its polar stationary phase. It also has overlap with ion exchange chromatography. Sometimes, HILIC is considered to be a hybrid of these techniques. HILIC was named in 1990 by Andrew Alpert, who described it as a type of liquid-liquid partition chromatography. He suggested that analytes elute in order of increasing polarity, a conclusion supported by review and re-evaluation of published data. The mechanism for HILIC is still not entirely understood, but it is thought to rely on analytes partitioning between the organic-rich mobile phase and a water-enriched layer that forms of the surface of the polar stationary phase, in a liquid-liquid extraction system. More polar analytes will have stronger interactions with the water-enriched layer and with the column itself, therefore being retained on the column for longer.
Sources: en.wikipedia.org
Cardarine is a common name for GW501516, a synthetic PPARδ agonist. It is not a steroid or a selective androgen receptor modulator. It was developed and studied as a research compound for metabolic pathways.
It binds to and activates PPARδ, a nuclear receptor that regulates genes related to fatty acid oxidation and energy use. This activation alters transcription in tissues such as skeletal muscle and liver. The full range of downstream effects in humans is not fully established.
No, cardarine is not known to occur naturally in plants, animals, or humans. It is a synthetic molecule produced for laboratory research. Products labeled as cardarine should therefore be treated as manufactured chemicals with variable purity.
It binds to and activates PPAR delta, a nuclear receptor that controls expression of genes related to fatty acid oxidation. This mechanism can alter energy metabolism in animal models. It is not a direct stimulant or fat-burning enzyme.