A practical reference on LC-MS/MS: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
Reviewed 2026-03-07. Anything still debated is marked as such rather than presented as settled.
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.
GW501516 acts as a selective agonist at PPARδ, a nuclear receptor that regulates transcription of genes involved in lipid handling and energy metabolism. Activation of PPARδ in preclinical models increases fatty acid oxidation, mitochondrial biogenesis, and exercise endurance in rodents. These effects have made the compound a subject of metabolic research and also a target for sport anti-doping rules. In humans, however, controlled studies are limited, and whether similar endurance or metabolic changes occur at tolerated exposures remains an open question. The receptor’s broad tissue distribution also means downstream effects may vary by organ and condition.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Appearance | White to off-white powder | Visual description for typical solid reference material. |
| Solubility | Poorly soluble in water; soluble in DMSO | Solubility depends on solvent, purity, and form. |
| Storage | Cool, dry, protected from light | Long-term storage often uses low temperature and desiccant. |
| Common analytical method | LC-MS/MS | Used for detection and quantification in biological matrices. |
| Common synonyms | GW-501516; GW501516; endurobol | Naming varies among literature, vendors, and databases. |
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.
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.
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.
== External links == amylin at the U.S. National Library of Medicine Medical Subject Headings (MeSH) "Amylin Nucleation Site". PDB Entry 1KUW. RCSB Protein Data Bank. doi:10.2210/pdb1kuw/pdb. Archived from the original on 16 April 2008. Retrieved 2008-05-28. Human DAP genome location and DAP gene details page in the UCSC Genome Browser. Human IAPP genome location and IAPP gene details page in the UCSC Genome Browser.
Following its blockbuster success as a veterinary antiparasitic, another Merck scientist, Mohamed Aziz, collaborated with the World Health Organization to test the safety and efficacy of ivermectin against onchocerciasis in humans. They found it to be highly safe and effective, triggering Merck to register ivermectin for human use as "Mectizan" in France in 1987. A year later, Merck CEO Roy Vagelos agreed that Merck would donate all ivermectin needed to eradicate river blindness. In 1998, that donation would be expanded to include ivermectin used to treat lymphatic filariasis. Ivermectin earned the title of "wonder drug" for the treatment of nematodes and arthropod parasites. Ivermectin has been used safely by hundreds of millions of people to treat river blindness and lymphatic filariasis. Half of the 2015 Nobel Prize in Physiology or Medicine was awarded jointly to Campbell and Ōmura for discovering ivermectin, "the derivatives of which have radically lowered the incidence of river blindness and lymphatic filariasis, as well as showing efficacy against an expanding number of other parasitic diseases".
Joullié (born 1927), Brazilian, American organic chemist Isabella Karle (1921–2017), American crystallographer Joyce Jacobson Kaufman (1929–2016), American chemist, Pharmacologist Judith Klinman (born 1941), American biochemist Teresa Kowalska (1946-2023), Polish chemist, co-founder of Acta Chromatographia Marisa Kozlowski, American organic chemist Stephanie Kwolek (1923–2014), American chemist, inventor of Kevlar Sine Larsen (1943–2025), Danish structural chemist and crystallographer Kathleen Lonsdale (1903–1971), British crystallographer Yvonne Connolly Martin (born 1936), American physical biochemist working on cheminformatics and computer-aided drug design in the US Marie Marynard Daly (1921–2001), First African American woman to earn her PhD in the United States Cynthia A.
== History == The earliest description of a lectin is believed to have been given by Peter Hermann Stillmark in his doctoral thesis presented in 1888 to the Imperial University of Dorpat. Stillmark isolated ricin, an extremely toxic hemagglutinin, from seeds of the castor plant (Ricinus communis). Although lectins were first discovered in plants, they are now known to be present throughout nature. The first lectin to be purified on a large scale and available on a commercial basis was concanavalin A, which is now the most-used lectin for characterization and purification of sugar-containing molecules and cellular structures. The legume lectins are probably the most well-studied lectins. Long before a deeper understanding of their numerous biological functions was developed, the plant lectins, also known as phytohemagglutinins, were noted for their particularly high specificity for foreign glycoconjugates (e.g., those of fungi and animals) and used in biomedicine for blood cell testing and in biochemistry for fractionation.
Sources: en.wikipedia.org
Pyruvate formate-lyase activating enzyme (PFL-AE) catalyzes the activation of PFL, a central enzyme in anaerobic glucose metabolism in microbes. Benzylsuccinate synthase (BSS) is a central enzyme in anaerobic toluene catabolism.
=== DEAE-D === DEAE-Dextran (DEAE-D) is a positively charged dextran derivative that can be used for vaccine production, gene therapy, protein stabilization, dyslipidemia prevention, flocculating agents, and many other applications. DEAE-D is also used for transfecting animal cells with foreign DNA. It is added to solution containing DNA meant for transfection. It binds and interacts with negatively charged DNA molecules and via an unknown mechanism brings about the uptake of nucleic acids by the cell. This procedure is highly suited for transient transfection used for various molecular biology studies.
=== Paraguay === The president of the Authentic Radical Liberal Party, Hugo Fleitas, applauded Maduro's capture, stating that "We celebrate the liberation of Venezuela from the oppressive regime of dictator Maduro" and "we hope for the restoration of democracy based on respect for the self-determination of the Venezuelan people, expressed at the polls in 2024 with the election of Edmundo González as their president." The Guasú Front issued a statement condemning the strikes, labelling as an "intolerable military aggression against Venezuela and all of Latin America."
Agathe Niehus, born on 28 December 1904 Gret Baumann, born on 8 February 1906 Franz Jung-Merker, born on 28 November 1908 Marianne Niehus, born on 20 September 1910 Helene Hoerni, born on 18 March 1914 None of the children continued in their father's field. The daughters, Agathe and Marianne, assisted in publishing work. During his marriage, Jung engaged in at least one extramarital relationship: with his patient and, later, fellow psychoanalyst Sabina Spielrein. A continuing affair with Toni Wolff, starting in 1910, has also been alleged. Jung confided in Freud that he had "'polygamous components' in himself" and that "'The pre-requisite of a good marriage, it seems to me, is the licence to be unfaithful'".
The first two roll-on/roll-off ferry berths in the Eastern Docks were opened on 30 June 1953. The first ro-ro ferry, the appropriately modified British Railways' SS Dinard, departed for Boulogne on 3 July 1953. Today, there are seven active docks for Ro-Ro vessels to utilise at Dover, one deconstructed dock and one unused dock for high-speed Ro-Ro watercraft. In 1966 well over 600,000 accompanied vehicles travelled through Dover's Eastern Docks en route to France or Belgium.
Sources: en.wikipedia.org
Cardarine targets PPARδ, a nuclear receptor involved in lipid and energy metabolism. It does not bind the androgen receptor in the way SARMs do.
Most methods use liquid chromatography with tandem mass spectrometry. Urine is common in anti-doping testing, and blood or plasma may be used in research.
Typical guidance is cool, dry, dark storage, often at low temperature and with desiccant. Stability data are limited, so storage conditions should be verified for each batch or supplier.
Cardarine is commonly known as GW501516 or GW-1516. These names refer to the same synthetic compound. It is not a brand-name approved medicine.