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 2026-02-12. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Appearance | White to off-white solid | Typical form of reference material |
| Solubility | Low in water; soluble in DMSO | Used to prepare stock solutions |
| Typical storage | -20 °C, desiccated, protected from light | Common laboratory practice |
| Analytical method | LC-MS/MS | Detects parent compound and metabolites |
| Common test matrix | Urine or blood | Used in anti-doping analysis |
PPARδ is a nuclear receptor that influences transcription of genes involved in fatty acid oxidation, lipid transport, and energy homeostasis. GW501516 binds and activates this receptor with high selectivity relative to PPARα and PPARγ in laboratory assays. Activation alters expression of target genes in skeletal muscle, liver, and adipose tissue in animal models. The exact clinical consequences of these changes in humans remain incompletely characterized, and observed effects in animals do not establish therapeutic benefit or safety.
Published studies have examined GW501516 in animal models of obesity, insulin resistance, and exercise endurance. Early human trials reportedly ended, and development was discontinued after preclinical findings raised concerns about cancer in some rodent studies. Regulatory agencies have not approved cardarine for any medical use. Its availability through non-pharmaceutical channels raises questions about identity, purity, and legal status that are separate from its laboratory pharmacology. Those questions are often addressed through analytical testing rather than assumptions about product labels.
Cardarine is a common name for GW501516, also GW-1516, a synthetic compound developed as a peroxisome proliferator-activated receptor delta (PPARδ) agonist. It belongs to a class of agents that modulate gene transcription related to lipid and energy metabolism. The compound was studied in preclinical and early clinical research for metabolic and cardiovascular conditions, but it did not progress to approved therapeutic use. Its name appears in fitness and sports contexts despite not being approved as a drug.
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.
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.
=== History === Obtaining a medical history is always the first "test", part of understanding the likelihood of significant disease, as detectable within the current limitations of clinical medicine. Yet heart problems often produce no symptoms until very advanced, and many symptoms, such as palpitations and sensations of extra or missing heart beats correlate poorly with relative heart health vs disease. Hence, a history alone is rarely sufficient to diagnose a heart condition.
In a meeting of the Quadrilateral Security Dialogue on the implications of the 2022 Russian invasion of Ukraine for the region, President Biden noted India's abstention, saying that most global allies were united against Russia. Speaking to the US Senate Foreign Relations Committee, US diplomat Donald Lu said the Biden administration was still considering sanctions against India over its S-400 deal with Russia, and its abstention at the UN. However, the Biden administration has ruled out secondary sanctions against India for its considerable oil imports or defence engagement from Russia.
=== Dinosaurs === It has been theorized that the neural spines of Spinosaurus, Ouranosaurus, and other dinosaurs with similar spines had humps, rather than the sailfins they are commonly depicted as having. If true, such humps would aid with heat regulation, storing of lipids for egg production, and storing fat for long migrations. Concavenator corcovatus is named for its hump (the name means "hunchback hunter from Cuenca"), but its use is debated, with theories including heat regulartion, attracting mates, intimidating rivals, or fat storage.
=== Phase 2 === AGX-201 (histamine dihydrochloride salt) – histamine H1 receptor antagonist and histamine H3 receptor agonist – migraine [7] BHV-2100 – transient receptor potential cation channel subfamily M member 3 (TRPM3) antagonist – migraine [8] Botulinum toxin A longer acting (IPN-10200; mrBoNT) – acetylcholine release inhibitor and neuromuscular blocking agent – migraine [9] CAM-01 (C-AM-01) – undefined mechanism of action – migraine [10] Dihydroergotamine mesilate (DFN-19) – non-selective monoamine receptor modulator and ergoline – migraine [11] Doxepin intranasal (Dolorac) – tricyclic antidepressant (non-selective monoamine reuptake inhibitor and receptor modulator and other actions) – headache [12] Elismetrep (K-304; MT-8554) – transient receptor potential cation channel subfamily M member 8 (TRPM8) antagonist – migraine [13] Erenumab (Aimovig; AMG-334) – monoclonal antibody against calcitonin gene-related peptide receptor (CGRPR) – headache [14] Eslicarbazepine acetate (Aptiom; BIA 2-093; ESL; Exalief; SEP-0002093; SEP-2093; Stedesa; Zebinix) – sodium channel blocker – migraine [15] IONIS-PKKRx (ISIS-546254; ISIS-PKKRx) – antisense oligonucleotide against kallikrein – migraine [16] Ketoprofen topical (ELS-M11; Topofen) – COX inhibitor/NSAID – migraine [17] LAT-8881 (AOD9604; Tyr-hGH171191) – human growth hormone protein fragment and lanthionine synthetase C-like protein (LanCL) ligand – migraine [18] LU-AG09222 (ALD-1910) – monoclonal antibody against pituitary adenylate cyclase-activating polypeptide (PACAP) – migraine [19] LY-3451838 (PACAP-38 antibody) – monoclonal antibody against pituitary adenylate cyclase-activating polypeptide (PACAP) – migraine [20] Lysergic acid diethylamide (LSD; MM-120) – non-selective serotonin receptor agonist and psychedelic hallucinogen – cluster headache [21] MTX-101 – undefined mechanism of action – migraine [22] Pasireotide (Signifor; SOM-230) – somatostatin receptor agonist – cluster headache [23] Prabotulinumtoxin A (ABP-450; DWP-450; Evosyal; Jeuveau; Nabota; Nuceiva) – acetylcholine release inhibitor and neuromuscular blocking agent – migraine [24] Sepranolone (isoallopregnanolone; UC-1010) – GABAA receptor negative allosteric modulator and neurosteroid – menstrual migraine [25] TRV-250 – δ-opioid receptor (DOR) agonist – migraine [26] (R)-Verapamil – calcium channel blocker and other actions – cluster headache [27] Zelminemab (AMG-301) – monoclonal antibody against pituitary adenylate cyclase-activating polypeptide type I receptor (PAC1R) – migraine [28]
Ribulose-1,5-bisphosphate carboxylase/oxygenase, commonly known by the abbreviations RuBisCo, rubisco, RuBPCase, or RuBPco, is an enzyme (EC 4.1.1.39) involved in the light-independent (or "dark") part of photosynthesis, including the carbon fixation by which atmospheric carbon dioxide is converted by plants and other photosynthetic organisms to energy-rich molecules such as glucose. It emerged approximately four billion years ago in primordial metabolism prior to the presence of oxygen on Earth. It is the most abundant enzyme on Earth. In chemical terms, it catalyzes the carboxylation of ribulose-1,5-bisphosphate (also known as RuBP).
Sources: en.wikipedia.org
=== 14 December === Three explosions were heard in the centre of Kyiv; President Zelenskyy claimed that Ukrainian air defence forces shot down 13 Shahed-136 drones. Reports emerged that U.S. officials were finalising and preparing to announce a plan to provide Ukraine with the sophisticated Patriot air defence system, agreeing to an urgent request from Ukrainian leaders amid increasing Russian missile attacks against Ukraine's infrastructure. The Biden administration was reluctant to deploy the system for months, as a Patriot battery complex would need at least 90 trained troops to operate and maintain it, along with concerns that it would provoke Russia to escalate. The Ukrainian Parliament's Commissioner for Human Rights Dmytro Lubinets claimed that a children's torture chamber had been uncovered in Kherson. Andrii Yermak, Chief of Staff of the Office of President Zelenskyy, stated that they released around 64 military personnel and a US citizen during a prisoner swap deal with Russia.
In the 1870s, Paul Ehrlich developed a staining technique using a combination of an acidic and basic dye that could distinguish different types of white blood cells and allow red blood cell morphology to be examined. Dmitri Leonidovich Romanowsky improved on this technique in the 1890s, using a mixture of eosin and aged methylene blue to produce a wide range of hues not present when either of the stains was used alone. This became the basis for Romanowsky staining, the technique still used to stain blood smears for manual review. The first techniques for measuring hemoglobin were devised in the late 19th century, and involved visual comparisons of the colour of diluted blood against a known standard. Attempts to automate this process using spectrophotometry and colorimetry were limited by the fact that hemoglobin is present in the blood in many different forms, meaning that it could not be measured at a single wavelength. In 1920, a method to convert the different forms of hemoglobin to one stable form (cyanmethemoglobin or hemiglobincyanide) was introduced, allowing hemoglobin levels to be measured automatically. The cyanmethemoglobin method remains the reference method for hemoglobin measurement and is still used in many automated hematology analyzers. Maxwell Wintrobe is credited with the invention of the hematocrit test. In 1929, he undertook a PhD project at the University of Tulane to determine normal ranges for red blood cell parameters, and invented a method known as the Wintrobe hematocrit.
=== From aldehydes === The Tishchenko reaction involves disproportionation of an aldehyde in the presence of an anhydrous base to give an ester. Catalysts are aluminium alkoxides or sodium alkoxides. Benzaldehyde reacts with sodium benzyloxide (generated from sodium and benzyl alcohol) to generate benzyl benzoate. The method is used in the production of ethyl acetate from acetaldehyde.
=== Structure === Scaffolds are used in tissue engineering to create an environment with similar mechanical properties of the native tissue. Scaffolds must be biocompatible and have high compressive strength. Scaffolds can be created from hydrogels, polymers or other material. Hydrogels are lightly cross-linked polymer networks swollen with water. Degree of crosslinking, porosity, and polymer composition can be tuned to create a hydrogel with similar properties to native cartilage. Researchers have been exploring the use of hydrogels as a cartilage substitute since the 1970s.
Sources: en.wikipedia.org
Zortac is voiced by Yasuhiko Kawazu (川津 泰彦, Kawazu Yasuhiko). Thousanian Gineka (サウザン星人ギネーカ, Sauzan Seijin Ginēka): A profligate from Planet Thousan who murdered countless innocents via his Kaijuki Million Missile (ミリオンミサイル, Mirion Misairu), which is capable of transforming into a stealth aircraft, in a specialized game he and his friends set up with a rare jewel as a marker. Gineka is deleted by the Deka Wing Cannon. Gineka is voiced by Kappei Yamaguchi (山口 勝平, Yamaguchi Kappei). Handorean Decho (ハンドレ星人デーチョ, Handore Seijin Dēcho) and Tentean Siroger (テンテ星人シロガー, Tente Seijin Shirogā): Gineka's accomplices from Planets Handore and Tente, respectively, who join him in his game after rebuilding Durden's and Dazgonelr's respective Kaijuki, Ultimate Evil and Embarns, before they are deleted by Deka Wing Robo. Decho and Siroger are voiced by Akimitsu Takase (高瀬 右光, Takase Akimitsu) and Junji Kitajima (北島 淳司, Kitajima Junji) respectively. Tenkaonian Raja Namunan (テンカオ星人ラジャ・ナムナン, Tenkao Seijin Raja Namunan): A seahorse-themed criminal from Planet Tenkao who is charged with 103 counts of burglary and who murdered Detective Chou San's daughter 13 years prior to the series, though the murder could not originally be connected to him. After he is successfully charged with the murder in the present, Namunan attempts to escape justice in his Kaijuki, Knight Chaser 2 (ナイトチェイサー2, Naito Cheisā Tsū), only to be deleted by the Deka Wing Cannon. Raja Namunan is voiced by Ryōichi Tanaka (田中 亮一, Tanaka Ryōichi).
Caspar Wistar, known for advocating compulsory vaccination; Benjamin Smith Barton, a botany and Native American culture expert; and Dr. Benjamin Rush, a Declaration signatory interested in the medicinal properties of cinchona bark. Humboldt's companion, Charles Willson Peale, a painter and lay scientist, introduced him to his unique museum, dubbed the "School of Wisdom." The museum held an eclectic array of specimens, including stuffed animals, bizarre artifacts, and a collection of paintings for sale. Peale also showcased a device called the physiognotrace, which allowed individuals to trace silhouettes, and Humboldt participated in creating a series of his own profiles.
== Medical uses == Drotrecogin alfa does not improve mortality in severe sepsis or septic shock but does increase bleeding risks. Therefore, a 2012 Cochrane review recommended that clinicians and policymakers not recommend its use and Eli Lilly has announced the discontinuation of all clinical trials.
=== Obesity and metabolic disorders === Microbial therapeutics are also being explored as treatments for obesity and metabolic diseases such as diabetes. Certain gut microorganisms influence how the body absorbs nutrients, stores energy, and regulates blood sugar. By changing the activity or composition of these microbes, it may be possible to improve metabolic health. In addition, genetically engineered bacterial and yeast have been developed to produce hormones that help regulate appetite and glucose levels. For example, some engineered microbes release substances similar to the hormone glucagon-like peptide-1 (GLP-1), which supports insulin release and promotes feelings of fullness. Because these microbes can live in the gut, they may provide longer-lasting effects than traditional medications.
== Awards and recognition == Fellow, American Association for the Advancement of Science (1995) Fellow, Academy of Toxicological Sciences (2000) Public Communications Award, Society of Toxicology (2014) Excellence in Pharmacology/Toxicology Lifetime Award, PhRMA Foundation (2015) David Rall Medal, National Academy of Medicine (2020) Merit Award, Society of Toxicology (2024)
Sources: en.wikipedia.org
Anti-doping and clinical laboratories commonly use liquid chromatography-tandem mass spectrometry. The method can identify GW501516 and its metabolites in urine or blood. Detection depends on sample timing and the amount present.
PPARδ is a nuclear receptor that regulates genes linked to fatty acid oxidation and energy metabolism. Activation can alter lipid handling and energy use in experimental models. The full range of effects in humans is still under study.
The solid compound is generally stable when kept cold, dry, and protected from light. Solutions may degrade faster, so laboratory protocols often specify fresh preparation or cold storage. Stability can depend on solvent, concentration, and container.
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.