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 2026-08-01. Where a claim depends on a specific study, the study is described rather than over-claimed.
Cardarine is a common name for GW501516, a synthetic compound first described in the 1990s as a selective agonist of the peroxisome proliferator-activated receptor delta. It was studied in preclinical models for metabolic and cardiovascular conditions, but it has not been approved as a medicine in the United States, Europe, or other major jurisdictions. Retail products labeled as cardarine are generally research chemicals or supplements, not pharmaceutical formulations. Because human safety and efficacy data remain limited, regulatory agencies treat it as an unapproved substance rather than a therapeutic product.
Sporting authorities added GW501516 to prohibited lists after it appeared in athlete samples and online markets. The World Anti-Doping Agency classifies it as a hormone and metabolic modulator, and its use can lead to an anti-doping rule violation. Some early laboratory work suggested effects on fatty acid oxidation and endurance-related metabolism in animals, but those findings do not establish safe or effective use in people. Reports of adverse events in humans are scarce and often anecdotal, which complicates risk assessment.
Legal status varies by country. In some places, cardarine is controlled under medicines or psychoactive substances laws; in others, it may be sold with minimal oversight as a research chemical. Customs agencies have intercepted shipments, and several national health agencies have issued warnings about products marketed for bodybuilding or performance enhancement. The lack of a standardized pharmaceutical supply means identity, purity, and contamination levels can differ widely between samples. These factors make cardarine a regulatory and public health concern rather than a conventional prescription drug.
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.
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.
| Property | Value | Notes |
|---|---|---|
| IUPAC name | {4-[({4-methyl-2-[4-(trifluoromethyl)phenyl]-1,3-thiazol-5-yl}methyl)sulfanyl]phenoxy}acetic acid | Systematic name for GW501516 |
| CAS Registry Number | 317318-70-0 | Unique identifier for the parent compound |
| Molecular formula | C21H18F3NO3S2 | Includes carbon, hydrogen, fluorine, nitrogen, oxygen, and sulfur |
| Molecular weight | 453.5 g/mol | Approximate value for the neutral form |
| Appearance | White to off-white powder | Typical description for purified laboratory material |
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.
Published human data are sparse and mostly come from early-phase trials. Those studies examined short-term changes in lipids, glucose, and exercise capacity, but they were not large enough to establish efficacy or long-term safety. Some animal experiments reported increased running endurance, yet such findings do not prove a performance benefit in people. Anti-doping laboratories detect GW501516 and its metabolites in urine or blood using liquid chromatography-tandem mass spectrometry. Detection windows depend on dose, sample type, and individual metabolism. The method is sensitive enough to identify trace residues in tested samples.
PPARδ is a nuclear receptor that regulates gene expression related to fatty acid oxidation, glucose homeostasis, and mitochondrial function. GW501516 binds to this receptor with high affinity and activates downstream signaling in skeletal muscle and other tissues. Animal studies reported increased endurance and altered fuel preference, but human data remain limited and inconsistent. The precise relationship between receptor activation and observed physiological changes is still an area of active investigation. Researchers have also examined whether the compound affects inflammation or cell proliferation. No approved therapeutic indication exists for cardarine.
In laboratory settings, cardarine is studied as a tool compound for probing PPARδ biology. Published experiments often use cell cultures, rodent models, or isolated tissues. Some investigations focus on metabolic effects, while others assess potential risks such as carcinogenicity observed in long-term animal studies. Because human trials are sparse, most knowledge comes from preclinical work and adverse event reports. Scientific literature frequently notes the gap between animal findings and human outcomes. The compound is not a dietary supplement and is not intended for human consumption.
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.
=== Factors increasing cortisol levels === Viral infections increase cortisol levels through activation of the HPA axis by cytokines. Intense (high VO2 max) or prolonged aerobic exercise transiently increases cortisol levels to increase gluconeogenesis and maintain blood glucose; however, cortisol declines to normal levels after eating (i.e., restoring a neutral energy balance). Severe trauma or stressful events can elevate cortisol levels in the blood for prolonged periods. Low-carbohydrate diets cause a short-term increase in resting cortisol (≈3 weeks), and increase the cortisol response to aerobic exercise in the short- and long-term. Increase in the concentration of ghrelin, the hunger stimulating hormone, increases levels of cortisol.
The first benzodiazepine, chlordiazepoxide (Librium), was synthesized in 1955 by Leo Sternbach while working at Hoffmann–La Roche on the development of tranquilizers. The pharmacological properties of the compounds prepared initially were disappointing, and Sternbach abandoned the project. Two years later, in April 1957, co-worker Earl Reeder noticed a "nicely crystalline" compound left over from the discontinued project while spring-cleaning in the lab. This compound, later named chlordiazepoxide, had not been tested in 1955 because of Sternbach's focus on other issues. Expecting pharmacology results to be negative and hoping to publish the chemistry-related findings, researchers submitted it for a standard battery of animal tests. The compound showed very strong sedative, anticonvulsant, and muscle relaxant effects. These impressive clinical findings led to its speedy introduction throughout the world in 1960 under the brand name Librium. Following chlordiazepoxide, diazepam marketed by Hoffmann–La Roche under the brand name Valium in 1963, and for a while the two were the most commercially successful drugs. The introduction of benzodiazepines led to a decrease in the prescription of barbiturates, and by the 1970s, they had largely replaced the older drugs for sedative and hypnotic uses. The new group of drugs was initially greeted with optimism by the medical profession, but gradually, concerns arose; in particular, the risk of dependence became evident in the 1980s.
Measles vaccine is a live attenuated vaccine that protects against becoming infected with measles. Nearly all of those who do not develop immunity after a single dose develop it after a second dose. When the rate of vaccination within a population is greater than 92%, outbreaks of measles typically no longer occur; however, they may occur again if the rate of vaccination decreases. The vaccine's effectiveness lasts many years. It is unclear if it becomes less effective over time. The vaccine may also protect against measles if given within a couple of days after exposure to measles. Measles is a highly contagious viral illness that can lead to serious complications, including pneumonia, acute encephalitis, and, in rare cases, long‑term neurological disease. Pregnant women are at increased risk of severe respiratory complications and adverse pregnancy outcomes such as pregnancy loss and premature birth. The vaccine is generally safe, even for those infected by HIV. Most children do not experience any side effects; those that do occur are usually mild (such as fever, rash, pain at the site of injection, and joint stiffness) and short-lived. Anaphylaxis has been documented in about 3.5–10 cases per million doses. Rates of Guillain–Barré syndrome, autism and inflammatory bowel disease do not appear to be increased by measles vaccination. The vaccine is available both by itself and in combinations such as the MMR vaccine (a combination with the rubella vaccine and mumps vaccine) or the MMRV vaccine (a combination of MMR with the chickenpox vaccine).
In order for the acyl-CoA to enter the mitochondrion the carnitine shuttle is used: Acyl-CoA is transferred to the hydroxyl group of carnitine by carnitine palmitoyltransferase I, located on the cytosolic faces of the outer and inner mitochondrial membranes. Acyl-carnitine is shuttled inside by a carnitine-acylcarnitine translocase, as a carnitine is shuttled outside. Acyl-carnitine is converted back to acyl-CoA by carnitine palmitoyltransferase II, located on the interior face of the inner mitochondrial membrane. The liberated carnitine is shuttled back to the cytosol, as an acyl-CoA is shuttled into the mitochondrial matrix. Beta oxidation, in the mitochondrial matrix, then cuts the long carbon chains of the fatty acids (in the form of acyl-CoA molecules) into a series of two-carbon (acetate) units, which, combined with co-enzyme A, form molecules of acetyl CoA, which condense with oxaloacetate to form citrate at the "beginning" of the citric acid cycle. It is convenient to think of this reaction as marking the "starting point" of the cycle, as this is when fuel - acetyl-CoA - is added to the cycle, which will be dissipated as CO2 and H2O with the release of a substantial quantity of energy captured in the form of ATP, during the course of each turn of the cycle and subsequent oxidative phosphorylation.
Sources: en.wikipedia.org
=== 1940s === 1942: American geologist Marguerite Williams became the first African-American woman to receive a PhD in geology in the United States. She completed her doctorate, entitled A History of Erosion in the Anacostia Drainage Basin, at Catholic University. 1947: Gerty Cori became the first woman to receive the Nobel Prize in Physiology or Medicine, which she received along with Carl Ferdinand Cori "for their discovery of the course of the catalytic conversion of glycogen", and Bernardo Alberto Houssay "for his discovery of the part played by the hormone of the anterior pituitary lobe in the metabolism of sugar". 1947: Marie Maynard Daly became the first Black woman in the United States to earn a Ph.D. in chemistry, and went on to perform research that would define how cholesterol clogged arteries, paving the way for a broad understanding that diet affects heart health. 1949: Dorothy Vaughan becomes the first African-American woman to supervise a group of staff at the Langely Research Center, a NASA field center.
== History == A digital ion trap (DIT) is an ion trap having a trapping waveform generated by the rapid switching between discrete high-voltage levels. The timing of the high voltage switch is controlled precisely with digital electronic circuitry. Ion motion in a quadrupole ion trap driven by a rectangular wave signal was theoretically studied in 1970s by Sheretov, E.P. and Richards, J.A. Sheretov also implemented the pulsed waveform drive for the quadrupole ion trap working in mass-selective instability mode, although no resonance excitation/ejection was used. The idea was substantially revisited by Ding L. and Kumashiro S. in 1999, where the ion stability in the rectangular wave quadrupole field was mapped in the Mathieu space a-q coordinate system, with the parameters a and q having the same definition as the Mathieu parameters normally used in dealing with sinusoidal RF driven quadrupole field. The secular frequency dependence on the a, q parameters was also derived thus the foundation was laid for many modern ion trap operation modes based on the resonance excitation. Also, in 1999, Peter T.A. Reilly began trapping and subsequently ablating and mass analyzing the product ions from nanoparticles obtained from car exhaust with a primitive hybrid square wave/sine wave driven 3D ion trap. In 2001 Reilly attended the 49th American Society for Mass Spectrometry (ASMS) Conference on Mass Spectrometry and Applied Topics where he presented his nanoparticle mass analysis work and met Li Ding for the first time.
=== Final months === In 2004, the team returned after Christmas to long hours, stressful working conditions, and no guarantee that Half-Life 2, which was costing $1 million a month to develop, would be finished soon. However, Newell felt that momentum was gathering, with the team producing about three hours of gameplay per month. In March, they created the first version playable from start to finish and stopped development for a week to play through. Major changes by this point included the cutting of the Borealis, the replacement of the jet ski with an airboat, and introducing the physics-manipulating gravity gun earlier. Feedback was positive across the company. Newell recalled: "The fact that you could go from one end of the game to the other was a really big thing for us. Then we knew it just had to get better – but it was all there." After several months of bug fixes and playtesting, Half-Life 2 was completed on October 13, 2004.
Cytokinins (CKs) are a group of chemicals that influence cell division and shoot formation. They also help delay senescence of tissues, are responsible for mediating auxin transport throughout the plant, and affect internodal length and leaf growth. They were called kinins in the past when they were first isolated from yeast cells. Cytokinins and auxins often work together, and the ratios of these two groups of plant hormones affect most major growth periods during a plant's lifetime. Cytokinins counter the apical dominance induced by auxins; in conjunction with ethylene, they promote abscission of leaves, flower parts, and fruits. Among the plant hormones, the three that are known to help with immunological interactions are ethylene (ET), salicylates (SA), and jasmonates (JA), however more research has gone into identifying the role that cytokinins play in this. Evidence suggests that cytokinins delay the interactions with pathogens, showing signs that they could induce resistance toward these pathogenic bacteria. Accordingly, there are higher CK levels in plants that have increased resistance to pathogens compared to those which are more susceptible. For example, pathogen resistance involving cytokinins was tested using the Arabidopsis species by treating them with naturally occurring CK (trans-zeatin) to see their response to the bacteria Pseudomonas syringa. Tobacco studies reveal that over expression of CK inducing IPT genes yields increased resistance whereas over expression of CK oxidase yields increased susceptibility to pathogen, namely P. syringae.
== See also == Style of the Dutch sovereign Regalia of the Netherlands Flags of the Dutch royal family Succession to the Dutch throne List of heirs to the Dutch throne Lists of rulers in the Low Countries Inauguration of the Dutch monarch List of Dutch royal consorts Monarchy of the Netherlands
Sources: en.wikipedia.org
== Further reading == Nualart F, Rivas C, Montecinos V, Godoy A, Guaiquil V, Golde D, Vera J (2003). "Recycling of vitamin C by a bystander effect". J Biol Chem. 278 (12): 10128–33. doi:10.1074/jbc.M210686200. hdl:10533/174378. PMID 12435736.
== Further reading == Pohlschroder, Mechthild; Pfeiffer, Friedhelm; Schulze, Stefan; Halim, Mohd Farid Abdul (1 September 2018). "Archaeal cell surface biogenesis". FEMS Microbiology Reviews. 42 (5): 694–717. doi:10.1093/femsre/fuy027. PMC 6098224. PMID 29912330.
PCR allows rapid production of short pieces of DNA, even when not more than the sequence of the two primers is known. This ability of PCR augments many methods, such as generating hybridization probes for Southern or northern blot hybridization. PCR supplies these techniques with large amounts of pure DNA, sometimes as a single strand, enabling analysis even from very small amounts of starting material. The task of DNA sequencing can also be assisted by PCR. Known segments of DNA can easily be produced from a patient with a genetic disease mutation. Modifications to the amplification technique can extract segments from a completely unknown genome, or can generate just a single strand of an area of interest. PCR has numerous applications to the more traditional process of DNA cloning. It can extract segments for insertion into a vector from a larger genome, which may be only available in small quantities. Using a single set of 'vector primers,' it can also analyze or extract fragments that have already been inserted into vectors. Some alterations to the PCR protocol can generate mutations (general or site-directed) of an inserted fragment. Sequence-tagged sites is a process where PCR is used as an indicator that a particular segment of a genome is present in a particular clone. The Human Genome Project found this application vital to mapping the cosmid clones they were sequencing and to coordinating the results from different laboratories.
Under the Reagan administration, Project Socrates determined that the Soviet Union addressed the acquisition of science and technology in a manner radically different to the United States. The US prioritized indigenous research and development in both the public and private sectors. In contrast, the USSR placed greater emphasis on acquiring foreign technology, which it did through both covert and overt means. However, centralized state planning kept Soviet technological development greatly inflexible. This was exploited by the US to undermine the strength of the Soviet Union and thus foster its reform.
Sources: en.wikipedia.org
No. Major drug regulators have not approved GW501516 for treating any medical condition. Products sold as cardarine are typically unapproved research chemicals or supplements, so their contents and safety are not assured.
It is prohibited by the World Anti-Doping Agency as a hormone and metabolic modulator. Athletes who test positive for GW501516 can face sanctions, including suspensions and loss of results.
Cardarine is a common or trade-style name, while GW501516 is the research code for the same chemical entity. Some sources also use Endurobol or GSK-516. The names refer to the same compound, not distinct drugs.
Cardarine targets PPARδ, a nuclear receptor involved in lipid and energy metabolism. It does not bind the androgen receptor in the way SARMs do.