Everything below concerns LC-MS/MS. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Updated 2025-12-30. 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.
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.
| 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 |
Cardarine is a common name for GW501516, a synthetic compound developed in the 1990s through research collaborations involving GlaxoSmithKline. It belongs to a class of molecules known as peroxisome proliferator-activated receptor delta agonists. Early studies explored its effects on lipid metabolism and energy expenditure in animal models. The compound was never approved as a human medicine, and clinical development was discontinued. In the years since, it has appeared in fitness and bodybuilding communities as a performance-enhancing substance. Regulatory agencies classify it as an unapproved drug.
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 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.
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.
Die offizielle Schreibweise wurde 1975 von einer Kommission der Gesellschaft Deutscher Chemiker, der Schweizerischen Chemischen Gesellschaft und der Gesellschaft Österreichischer Chemiker geändert und an die international übliche Schreibweise Iod angepasst. Dementsprechend wurde auch das Elementsymbol von J auf I geändert.
== Vorkommen == Iod ist abgesehen von Astat wesentlich seltener als die übrigen Halogene. In der Natur ist es weit verbreitet, jedoch nur in Form seiner Verbindungen, zum Beispiel angereichert (0,02–1 %) im Chilesalpeter, hauptsächlich in Form von Natriumiodat (NaIO3), aber auch Natriumperiodat (NaIO4) und Lautarit (Ca(IO3)2). In geringen Spuren ist es in Böden und Gesteinen nachweisbar. Im Durchschnitt enthält 1000 Gramm wasserfreier Feinboden aus dem deutschen Raum etwa 2,5 Milligramm Iod. Der Iodgehalt des Bodens ist wesentlich für die Versorgung der Bevölkerung mit natürlichem Iod. Als Iodwasserstoff kommt es in geringsten Mengen in vulkanischen Gasen vor. Lösliche Iodverbindungen wie Alkali- und Erdalkaliiodide werden während der Verwitterung von Gesteinen durch Regenwasser freigesetzt oder zerfallen bei höheren Temperaturen. So gelangen sie ins Grundwasser und schließlich in die Meere. Einige Mineralwässer enthalten Iod. Die Mineralquelle von Woodhall Spa in Lincolnshire (England) bringt Wasser hervor, das durch Iod braun gefärbt ist. Im Meerwasser liegt die Menge an Iod bei 0,05 Milligramm pro Liter. Es kommt dort in Form von Iodid (I−) und Iodat (IO3−) in einer Konzentration von etwa 500 nmol/L vor. Die Verteilung variiert in Oberflächenwasser im Allgemeinen von 0–200 nmol I−/L. In der Erdatmosphäre ist Iod in Form von organischen Verbindungen oder anorganisch in Form von Iodoxid (IO), Iodnitrat oder höheren Oxiden zu finden. Für die Stratosphäre gibt es wenig Informationen und eine obere Grenze von 0,1 ppt für anorganisches Iod.
Über Algenfeldern an Küsten wurden hohe Konzentrationen von mehr als 10 ppt IO nachgewiesen und auch auf dem tropischen Atlantik wurde das Iodoxid-Radikal nachgewiesen. Organische Iodverbindungen kann man aus Meeresalgen (19 Gramm Iod pro Kilogramm Trockenmasse), Tangen und Schwämmen (bis zu 14 Gramm Iod pro Kilogramm Trockenmasse) isolieren. Die globale Menge Iod in Meerwasser wird auf 90 Milliarden Tonnen geschätzt, die derzeit (2022) bekannten globalen Iodreserven betragen 6,2 Millionen Tonnen. Eine Knappheit ist trotz der relativen Seltenheit von Iod deshalb nicht gegeben oder zu erwarten. Das spiegelt sich auch im Preis wider, der 2021 deutlich unter dem Höchststand aus dem Jahr 2013 (bis zu 85 $ pro kg) bei durchschnittlich 36,5 $ pro kg notierte. Die Gewinnung aus Seegras und Algen spielt dabei derzeit eine untergeordnete Rolle, da die Gewinnung als Nebenprodukt aus dem Bergbau bzw. Gas- und Ölförderung kommerziell erfolgreicher ist. Vor 1959 war diese Form der Iodgewinnung jedoch vorherrschend. Die weltweite Iodförderung betrug 2020 über 30.000 Tonnen, ohne Fördermengen aus den USA, die diese als Geschäftsgeheimnis seit 2005 nicht mehr veröffentlichen. Größter globaler Iodproduzent ist Chile mit seinen Nitratminen, aus denen ca. 2/3 der globalen Iodmengen gewonnen werden. Zweitgrößter Produzent ist Japan, wo Iod bei der Öl- und Gasförderung gewonnen wird, und auf Platz 3 der wichtigsten Quellen liegt Soleförderung aus Minen im nordwestlichen Oklahoma.
Sources: de.wikipedia.org
== Gewinnung und Darstellung == Früher gewann man Iod in Form von Iodiden und Iodaten, indem man die durch die Flut an den Strand angeschwemmten Tange einsammelte und verbrannte. Die erhaltene Asche enthielt etwa 0,1–0,5 % Iod. Diese Iodgewinnung hat heute jedoch nur noch lokale Bedeutung und macht ungefähr 2 % der Weltjahresproduktion aus. Die technische Gewinnung von Iod ist eng mit der Salpetergewinnung verknüpft. Das in den Mutterlaugen enthaltene Iodat wird durch Reduktion in elementares Iod umgewandelt. Im ersten Reaktionsschritt setzt man Schweflige Säure ein, um Iodsäure (Iodat ist das Anion dieser Säure) zu Iodwasserstoff zu reduzieren:
Sources: de.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.
It binds to and activates PPAR delta, a nuclear receptor that controls expression of genes related to fatty acid oxidation. This mechanism can alter energy metabolism in animal models. It is not a direct stimulant or fat-burning enzyme.