LC-MS/MS is one of those subjects where the details matter more than the headlines. This page pulls together the background, the mechanisms, and the practical points readers ask about most.
Last reviewed on 2026-06-04. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
In the fitness and bodybuilding literature, cardarine is frequently discussed as an endurance agent or fat-loss compound, although such claims are not supported by robust clinical evidence. Online descriptions often mix animal data, user anecdotes, and marketing language. Researchers who study PPARδ agonists distinguish between receptor activation in controlled experiments and unsupervised use of unverified products. The latter introduces unknown purity, dose, and interactions, making reported experiences difficult to interpret scientifically.
GW501516 acts as an agonist at peroxisome proliferator-activated receptor delta, a nuclear receptor involved in transcription of genes related to lipid handling and energy use. Activation of PPARδ can shift skeletal muscle toward greater fatty acid oxidation in animal models, which is one reason it drew interest for metabolic disease and exercise research. The exact downstream effects depend on tissue, species, dose, and duration. Human data are sparse, so many proposed benefits remain hypotheses rather than established clinical outcomes.
Laboratory studies have examined GW501516 in cell cultures and rodents for conditions such as dyslipidemia, insulin resistance, and obesity. Some trials in humans were initiated, but development was discontinued after preclinical findings raised concerns about cancer in certain models. Those findings do not prove that the compound causes cancer in people, but they contributed to regulatory caution. Later reviews often describe the evidence as preliminary and insufficient for assessing long-term safety.
| Property | Value | Notes |
|---|---|---|
| Primary target | PPARδ (NR1C2) | Nuclear receptor involved in lipid metabolism |
| Preclinical effect | Increased fatty acid oxidation | Observed in rodent studies |
| Key safety signal | Tumors in rodents after long-term exposure | Contributed to halted clinical development |
| Human trial status | No approved product; development stopped | Limited short-term metabolic data |
| Sport regulatory status | Prohibited at all times | WADA hormone and metabolic modulators class |
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.
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.
Cardarine is a common name for GW501516, a synthetic compound studied for its effects on lipid and glucose metabolism. It functions as an agonist at peroxisome proliferator-activated receptor delta, or PPARδ, a nuclear receptor that influences gene expression. The molecule is not a steroid, nor is it a selective androgen receptor modulator. It is also known in research and sports literature as GW-501516 and endurobol. Early laboratory work examined its metabolic activity in cell cultures and animal models.
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.
== Mechanical stress and activity indicators == Examining the effects that activities has upon the skeleton allows the archaeologist to examine who was doing what kinds of labor, and how activities were structured within society. Labor within the household may be divided according to gender and age, or be based on other social structures. Human remains can allow archaeologists to uncover these patterns. Living bones are subject to Wolff's law, which states that bones are physically affected and remodeled by physical activity or inactivity. Increases in mechanical stress tend to produce thicker and stronger bones. Disruptions in homeostasis caused by nutritional deficiency or disease or profound inactivity/disuse/disability can lead to bone loss. While the acquisition of bipedal locomotion and body mass appear to determine the size and shape of children's bones, activity during the adolescent growth period seems to exert a greater influence on the size and shape of adult bones than exercise later in life. Muscle or ligament attachment sites on bones (entheses) are also considered to be impacted by habitual biomechanical loading, leading to the occurrence of various entheseal changes. These changes are routinely used in the field to study activity-patterns.
=== 1950–2000 === In the 1950s, thiazide diuretics were developed by Merck scientists Karl H. Beyer, James M. Sprague, John E. Baer, and Frederick C. Novello and led to the marketing of the first drug of this class, chlorothiazide, under the trade name Diuril in 1958. The research leading to the discovery of chlorothiazide, leading to "the saving of untold thousands of lives and the alleviation of the suffering of millions of victims of hypertension" was recognized by a special Public Health Award from the Lasker Foundation in 1975. In 1953, Merck & Co. merged with Philadelphia-based Sharp & Dohme, Inc., becoming the largest U.S. drugmaker. Sharp and Dohme had acquired H. K. Mulford Company in 1929, adding smallpox vaccines to its portfolio. The combined company kept the trade name Merck in the United States and Canada, and as Merck Sharp & Dohme (MSD) outside these two countries. In 1965, Merck & Co. acquired Charles Frosst Ltd. of Montreal (founded 1899), creating Merck-Frosst Canada, Inc., as its Canadian subsidiary and pharmaceutical research facility. Merck & Co. closed this facility in July 2010 but reemerged in 2011 as Merck Canada. Maurice Hilleman, a scientist at Merck, developed the first mumps vaccine in 1967, the first rubella vaccine in 1969, and the first trivalent measles, mumps, rubella (MMR vaccine) in 1971. The incidence of rubella-associated birth defects fell from up to 10,000 per year in the U.S. to zero in the aftermath of the rubella vaccine's development.
A GnRH modulator, or GnRH receptor modulator, also known as an LHRH modulator or LHRH receptor modulator, is a type of medication which modulates the GnRH receptor, the biological target of the hypothalamic hormone gonadotropin-releasing hormone (GnRH; also known as luteinizing-releasing hormone, or LHRH). They include GnRH agonists and GnRH antagonists. These medications may be GnRH analogues like leuprorelin and cetrorelix – peptides that are structurally related to GnRH – or small-molecules like elagolix and relugolix, which are structurally distinct from and unrelated to GnRH analogues. GnRH modulators affect the secretion of the gonadotropins, luteinizing hormone (LH) and follicle-stimulating hormone (FSH), which in turn affects the gonads, influencing their function and hence fertility as well as the production of sex steroids, including that of estradiol and progesterone in women and of testosterone in men. As such, GnRH modulators can also be described as progonadotropic or antigonadotropic, depending on whether they act to increase or decrease gonadotropins. Shortly after the discovery of GnRH by Nobel laureates Guillemin and Schally, researchers tried to modify the GnRH decapeptide with the intent to create analogues that could activate or block the receptor. Subsequent to the development and introduction of GnRH analogues, non-peptide or small-molecule GnRH modulators were developed and introduced. All GnRH modulators are contraindicated in pregnancy (pregnancy category X).
=== Austrian Empire and Austria-Hungary === In 1814, by decisions of the Congress of Vienna, Tyrol was reunified and returned to Austria, becoming a crown land (Kronland) of the Austrian Empire. The formerly Salzburgian Zillertal, Brixental and Matrei were also permanently integrated into Tyrol. Administratively Vorarlberg was attached to the reconstituted Tyrol (formally as "the princely county of Tyrol with Vorarlberg" – die gefürstete Grafschaft Tirol mit Vorarlberg) as Kreis Bregenz until it became a crown land in its own right in the 1861 February Patent. Tyrol-proper (i.e. excluding Vorarlberg) was until 1849 divided into six Kreise: Oberinnthal (or Imst), Unterinnthal (Schwaz), Pusterthal (Bruneck), Etsch (Bozen), Trient and Rovereto. In 1849 this was reduced to three: Innsbruck, Brixen and Trient, which broadly corresponded with the modern North Tyrol, South + East Tyrol and Trentino respectively. These Kreise were briefly divided into modern-style political districts but were recentralised and divided into smaller "office districts" from 1853. Following the Austro-Hungarian Compromise of 1867 Tyrol was a Cisleithanian (Austrian) crown land within Austria-Hungary. The Kreise and office districts were abolished and political districts re-introduced in 1868.
== See also == Animal testing on invertebrates Microbiome in the Drosophila gut Eating behavior in Insects (Measurement) Fruit flies in space Genetically modified insect Gynandromorphism JETLAG gene List of Drosophila databases Spätzle (gene) Time flies like an arrow; fruit flies like a banana Transgenesis Zebrafish – another widely-used model organism in scientific research Enhancer-FACS-seq
Sources: en.wikipedia.org
Precursor compounds: these compounds are the starting molecules or substrates in a reaction. These may also be viewed as the reactants in a given chemical process. Chemical energy: chemical energy can be found in the form of high energy molecules. These molecules are required for energetically unfavourable reactions. Furthermore, the hydrolysis of these compounds drives a reaction forward. High energy molecules, such as ATP, have three phosphates. Often, the terminal phosphate is split off during hydrolysis and transferred to another molecule. Catalysts: these may be for example metal ions or coenzymes and they catalyze a reaction by increasing the rate of the reaction and lowering the activation energy. In the simplest sense, the reactions that occur in biosynthesis have the following format:
The flora of the Appalachians are diverse and vary primarily in response to geology, latitude, elevation and moisture availability. Geobotanically, they constitute a floristic province of the North American Atlantic Region. The Appalachians consist primarily of deciduous broad-leaf trees and evergreen needle-leaf conifers, but also contain the evergreen broad-leaf American holly (Ilex opaca), and the deciduous needle-leaf conifer, the tamarack, or eastern larch (Larix laricina). The dominant northern and high elevation conifer is the red spruce (Picea rubens), which grows from near sea level to above 4,000 ft (1,200 m) above sea level (asl) in northern New England and southeastern Canada. It also grows southward along the Appalachian crest to the highest elevations of the southern Appalachians, as in North Carolina and Tennessee. In the central Appalachians it is usually confined above 3,000 ft (900 m) asl, except for a few cold valleys in which it reaches lower elevations. In the southern Appalachians, it is restricted to higher elevations. Another species is the black spruce (Picea mariana), which extends farthest north of any conifer in North America, is found at high elevations in the northern Appalachians, and in bogs as far south as Pennsylvania. The Appalachians are also home to two species of fir, the boreal balsam fir (Abies balsamea), and the southern high elevation endemic, Fraser fir (Abies fraseri).
== Rice == From 2009 to 2019, Thailand's hom mali 105 (jasmine) rice has been declared the world's best rice five times. But in 2018, Cambodian Malys Angkor jasmine rice was the winner, and Vietnam's ST24 rice took top honours in 2019, causing panic among Thai rice producers as ST24 is half the price of Thai hom mali.
István Weszprémi Award, University Medical School of Debrecen (1977) Fogarty International Research Fellowship, NIH (1989–1990) Distinguished Scientist Award, Japanese Society for the Promotion of Science (1992) Pándy and Jendrassik Awards, Hungarian Society of Laboratory Medicine (1992, 2000) Széchenyi Professorial Scholarship (1997–2000) Medal for Hungarian Higher Education (1998) Medal of the Hungarian Public Health Scientific Society (2000, 2006) Albert Szent‑Györgyi Medal (2001) Hatvani Award of the City of Debrecen (2005) Semmelweis Award (2006) Öveges Professorial Scholarship (2006) Endre Hőgyes Award (2007) Leó Szilárd Professorial Scholarship (2009) Pro Auditoribus Universitatis Debreceniensis Award (2010) Pro Urbe Award of the City of Debrecen (2011) Krompecher Award, University of Debrecen (2013) Budapest Award (2013) WHO Regional Director’s Award (2019, 2023) H.R. Leavell Award, World Federation of Public Health Associations (2020) Ádám Szendei Award (2020) Officer’s Cross of the Order of Merit of Hungary (2022)
==== 2000s ==== 2000 – First Medical Inc., Amelung GmbH, ARK Scientific 2001 – ISOTEC (produces stable isotopes used in basic research and medical diagnostics) 2004 – Ultrafine (a supplier of contract manufacturing services for drug development), Tetrionics (a producer of high potency and cytotoxic active pharmaceutical ingredients) 2005 – JRH Biosciences, an industrial supplier of cell culture products for the pharmaceutical and biotechnology industries; Proligo Group, a global supplier of genomics research tools 2006 – Beijing Superior Chemicals, Iropharm, Pharmorphix, Advanced Separation Technologies (manufacturer of products for chiral chromatography) 2007 – Epichem acquired to expand capabilities in materials sciences and semiconductor markets; Molecular Medicine BioServices acquired to provide large-scale viral manufacturing capabilities; announced alliance with Sangamo BioSciences to develop zinc finger-based laboratory research reagents 2009 – ChemNavigator 2010 – Cerilliant Corporation, ACE Animals 2011 – Resource Technology Corp, Vetec Quimica Fina 2012 – Research Organics Inc., BioReliance (a toxicology and veterinary diagnostics company); BioReliance had previously been acquired by Invitrogen and subsequently sold to Avista Capital Partners. 2014 – Cell Marque 2015 – Combined with EMD Millipore to make MilliporeSigma.
Sources: en.wikipedia.org
==== Co-evolutionary evidence ==== An independent molecular analysis trying to establish the dates when bat ectoparasites (bedbugs) evolved came to the conclusion that bedbugs similar to those known today (all major extant lineages, all of which feed primarily on bats) had already diversified and become established over 100 million years ago, suggesting that they initially all evolved on non-bat hosts and "bats were colonized several times independently, unless the evolutionary origin of bats has been grossly underestimated". No analysis has provided estimates for the age of the flea lineages associated with bats. The oldest known members of a different lineage of bat ectoparasites (bat flies), however, are from roughly 20 million years ago, well after the origin of bats. The bat-ectoparasitic earwig family Arixeniidae has no fossil record but is not believed to originate more than 23 million years ago.
Hydroxyzine's predominant mechanism of action is as a potent and selective histamine H1 receptor inverse agonist. This action is responsible for its antihistamine and sedative effects. Unlike many other first-generation antihistamines, hydroxyzine has a lower affinity for the muscarinic acetylcholine receptors, and in accordance, has a lower risk of anticholinergic side effects. In addition to its antihistamine activity, hydroxyzine has also been shown to act more weakly as an antagonist of the serotonin 5-HT2A receptor, the dopamine D2 receptor, and the α1-adrenergic receptor. Similarly to the atypical antipsychotics, the comparably weak antiserotonergic effects of hydroxyzine likely underlie its usefulness as an anxiolytic. Other antihistamines without such properties have not been found to be effective in the treatment of anxiety. Hydroxyzine crosses the blood–brain barrier easily and exerts effects in the central nervous system. A positron emission tomography (PET) study found that brain occupancy of the H1 receptor was 67.6% for a single 30 mg dose of hydroxyzine. In addition, subjective sleepiness correlated well with the brain H1 receptor occupancy. PET studies with antihistamines have found that brain H1 receptor occupancy of more than 50% is associated with a high prevalence of somnolence and cognitive decline, whereas brain H1 receptor occupancy of less than 20% is considered to be non-sedative. Hydroxyzine also acts as a functional inhibitor of acid sphingomyelinase.
=== Freeze drying (lyophilized) === Donkey milk can be freeze-dried to preserve the biological quality of the milk, and so preserve its nutritional, functional, and cosmetic properties. This is possible because in freeze drying the milk is frozen and brought under vacuum at low temperatures. During this process, the water is removed by sublimation. The result is approximately ten percent of dry matter that is called lyophilized (or freeze-dried) donkey milk. This powder is easy to reconstitute. The lyophilized product has to be packaged without any oxygen. It has a shelf life of two years. Normally it is produced from pasteurized donkey milk so it is ready to use. Analysis of freeze-dried donkey's milk has demonstrated that the natural colour, flavours, nutrients, and bioactive substances of fresh donkey milk are retained. Spray-drying is another way to dry products, in which the milk is heated and vitamins and other important bioactive substances may get lost. In contrast, Freeze-drying does not require chemical preservatives and can be either consumed directly or re-hydrated easily. However, this method for is costly, and is practiced only by a few companies. This product is easy to find in Italy, where it was for the first time put on the market.
In cancer, the genomes of affected cells are rearranged in complex or unpredictable ways. In addition to single-nucleotide polymorphism arrays identifying point mutations that cause cancer, oligonucleotide microarrays can be used to identify chromosomal gains and losses (called comparative genomic hybridization). These detection methods generate terabytes of data per experiment. The data is often found to contain considerable variability, or noise, and thus Hidden Markov model and change-point analysis methods are being developed to infer real copy number changes. Two important principles can be used to identify cancer by mutations in the exome. First, cancer is a disease of accumulated somatic mutations in genes. Second, cancer contains driver mutations which need to be distinguished from passengers. Further improvements in bioinformatics could allow for classifying types of cancer by analysis of cancer driven mutations in the genome. Furthermore, tracking of patients while the disease progresses may be possible in the future with the sequence of cancer samples. Another type of data that requires novel informatics development is the analysis of lesions found to be recurrent among many tumors.
=== Municipal administration === The number of inhabitants in Le Havre is between 150,000 and 199,999 so the number of councillors is 59 members. The mayor, 41 aldermen and 17 deputies form the council of Le Havre elected in 2008. It meets on average once a month at the town hall. The debates are generally public except for certain proceedings. Le Havre has experienced many territorial extensions by annexing neighbouring communes:
Sources: en.wikipedia.org
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.
Small short-term human trials examined metabolic markers such as lipids and glucose. The trials did not continue after rodent cancer findings, so long-term human safety is unknown.
Controlled human trials have not established a performance benefit. Anecdotal reports exist, but they are not reliable evidence.
It binds and activates PPARδ, a nuclear receptor that influences gene expression related to fatty acid metabolism and energy balance. This mechanism has been studied mainly in animals and cell models, not established as a safe human therapy.