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.
Updated 2026-06-28. Numbers and descriptions here follow the published literature rather than marketing material.
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.
Products sold as cardarine have been found to contain incorrect compounds, variable amounts, or no active ingredient at all. Independent testing is required to verify identity and purity. Common analytical approaches include high-performance liquid chromatography, mass spectrometry, and nuclear magnetic resonance for structural confirmation. These methods can distinguish GW501516 from related PPAR agonists and from unrelated steroids. For regulators and researchers, such verification is central to interpreting both biological results and adverse event reports.
Cardarine is prohibited in competitive sport under the World Anti-Doping Agency code, where it is classified as a metabolic modulator. It is not approved as a prescription medicine in the United States, European Union, or other major markets. Regulatory action has focused on its presence in sports and in products marketed as research chemicals. Because it has no accepted medical indication, supply is often unregulated. This status creates legal and safety uncertainties for anyone who encounters the substance.
| 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 |
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.
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.
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.
H3A (aq) + H2O (l) ⇌ H3O+ (aq) + H2A− (aq) Ka1 H2A− (aq) + H2O (l) ⇌ H3O+ (aq) + HA2− (aq) Ka2 HA2− (aq) + H2O (l) ⇌ H3O+ (aq) + A3− (aq) Ka3 An inorganic example of a triprotic acid is orthophosphoric acid (H3PO4), usually just called phosphoric acid. All three protons can be successively lost to yield H2PO−4, then HPO2−4, and finally PO3−4, the orthophosphate ion, usually just called phosphate. Even though the positions of the three protons on the original phosphoric acid molecule are equivalent, the successive Ka values differ since it is energetically less favorable to lose a proton if the conjugate base is more negatively charged. An organic example of a triprotic acid is citric acid, which can successively lose three protons to finally form the citrate ion. Although the subsequent loss of each hydrogen ion is less favorable, all of the conjugate bases are present in solution. The fractional concentration, α (alpha), for each species can be calculated. For example, a generic diprotic acid will generate 3 species in solution: H2A, HA−, and A2−. The fractional concentrations can be calculated as below when given either the pH (which can be converted to the [H+]) or the concentrations of the acid with all its conjugate bases:
The presence of autoantibodies against citrullinated proteins in rheumatoid arthritis patients was first described in the mid-1970s when the biochemical basis of antibody reactivity against keratin and filaggrin was investigated. Subsequent studies demonstrated that autoantibodies from RA patients react with a series of different citrullinated antigens, including fibrinogen, deiminated Epstein–Barr virus nuclear antigen 1 and vimentin, which is a member of the intermediate filament family of proteins. Several assays for detecting ACPAs were developed in the following years, employing mutated citrullinated Vimentin (MCV-assay), filaggrin-derived peptides (CCP-assay) and viral citrullinated peptides (VCP-assay). A 2006 clinical study showed that anti viral citrullinated peptide (VCP) antibodies of the IgG and IgA isotypes represent a discriminating specific marker of rheumatoid arthritis from other chronic arthritides and disease controls, suggesting an independent production of each isotype. In 2010, ACPA testing has become substantial part of The 2010 ACR-EULAR classification criteria for rheumatoid arthritis.
Proteomics permits the quantitative analysis and detection of changes to proteins or protein biomarkers. Protein biomarkers detect a variety of biological changes, such as protein-protein interactions, post-translational modifications and immunological responses. Protein biomarkers are widely used in diagnostics due to their direct involvement in cellular functions and pathways. Protein biomarkers can provide direct information about the functional state of cells and tissues, offering insights into disease mechanisms. Techniques such as mass spectrometry, immunohistochemistry, ELISA, and flow cytometry are employed to detect protein biomarkers, which can indicate protein presence and quantification. For example, in about 20% of breast cancers, the cancer cells have an overexpression of the HER2 gene, leading to more aggressive tumor growth. HER2 status can be determined using IHC and FISH. HER2-positive breast cancers are treated with targeted therapies that specifically target the HER2 protein, inhibiting the growth of cancer cells.
Membrane interaction of alpha-synuclein modulates or affects its rate of aggregation. The membrane-mediated modulation of aggregation is very similar to that observed for other amyloid proteins such as IAPP and abeta. Aggregated states of alpha-synuclein permeate the membrane of lipid vesicles. They are formed upon interaction with peroxidation-prone polyunsaturated fatty acids (PUFA) but not with monounsaturated fatty acids and the binding of lipid autoxidation-promoting transition metals such as iron or copper provokes oligomerization of alpha-synuclein. The aggregated alpha-synuclein has a specific activity for peroxidized lipids and induces lipid autoxidation in PUFA-rich membranes of both neurons and astrocytes, decreasing resistance to apoptosis. Lipid autoxidation is inhibited if the cells are pre-incubated with isotope-reinforced PUFAs (D-PUFA).
The first generation uses linking technologies that conjugate drugs non-selectively to cysteine or lysine residues in the antibody, resulting in a heterogeneous mixture. This approach leads to suboptimal safety and efficacy and complicates optimization of the biological, physical and pharmacological properties. Site-specific incorporation of unnatural amino acids generates a site for controlled and stable attachment. This enables the production of homogeneous ADCs with the antibody precisely linked to the drug and controlled ratios of antibody to drug, allowing the selection of a best-in-class ADC. An Escherichia coli-based open cell-free synthesis (OCFS) allows the synthesis of proteins containing site-specifically incorporated non-natural amino acids and has been optimized for predictable high-yield protein synthesis and folding. The absence of a cell wall allows the addition of non-natural factors to the system to manipulate transcription, translation and folding to provide precise protein expression modulation.
Sources: en.wikipedia.org
The Department works at the intersection of organic chemistry (chemistry of natural products, chemistry of macrocyclic compounds, chemistry of elementorganic compounds), supramolecular chemistry (solution and self-process chemistry) and molecular biology. The head of the Department is Professor Igor S. Antipin, a corresponding member of the Russian Academy of Science, Doctor of Chemistry. The Department conducts research in the following fields:
United States civil aviation incidents are investigated by the National Transportation Safety Board (NTSB). NTSB officials piece together evidence from the crash site to determine likely cause, or causes. The NTSB also investigates overseas incidents involving US-registered aircraft, in collaboration with local investigative authorities, especially when significant loss of American lives occurs, or when the involved aircraft is American-built. In Venezuela, the organization tasked with investigating aviation accidents is the Ministry of Aquatic and Air Transport, more specifically the Directorate General for the Prevention and Investigation of Aeronautical Accidents.
2-Aminoisobutyric acid (Aib) is the non-proteinogenic amino acid with the structural formula H2N-C(CH3)2-COOH. The Aib residue is a component of tirzepatide, a commonly prescribed antidiabetic medication for treatment of type 2 diabetes. Although uncommon, it is also found in some natural products 2-Aminoisobutyric acid can be prepared from acetone cyanohydrin, by reaction with ammonia followed by hydrolysis. The compound is not chiral, unlike most amino acids. It is a strong helix inducer in peptides due to Thorpe–Ingold effect of its gem-dimethyl group. Oligomers of Aib form 310 helices.
Alexander Bont first made a name for himself when he killed the hero Defender. After that, he soon rose up the ranks and became the head of organized crime. The Fixer, the man who ordered the hit on Jack Murdock, paid up to Bont. When Daredevil found this out, he confronted Bont and had him arrested. Bont got out on bail. He later asked Matt Murdock for legal help, but was refused. When Bont was released from jail, he was now a bitter old man. He had found out that Daredevil was really Matt Murdock from The Globe and had acquired a possession of Mutant Growth Hormone (MGH). Bont learns how much the world has changed in his absence, including the death of his wife. Furious, Bont swears revenge on Daredevil. He meets with Melvin Potter and threatens to kill his young daughter, forcing Potter into working for him. Potter kidnaps Matt Murdock, then beats him. When White Tiger defeats Melvin Potter, Bont takes Mutant Growth Hormone to confront Daredevil. However, he overdoses on MGH, overloading his heart and killing him.
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.
Legal status varies by country, but cardarine is not approved as a medicine in major jurisdictions. It is often sold as a research chemical, a category that may not be lawful for human use. Buyers should check local laws and product labels carefully.