A practical reference on Reference standard: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
Reviewed 2026-08-01. Anything still debated is marked as such rather than presented as settled.
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.
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.
Literature on cardarine often separates receptor pharmacology from toxicology. Mechanistic papers describe PPARδ activation and gene expression changes, while safety assessments focus on carcinogenicity and species differences. Questions remain about whether rodent tumors arise through PPARδ-dependent or off-target mechanisms. Another open area is how human metabolism and exposure compare with those in animal studies. Analytical methods such as liquid chromatography–mass spectrometry are used to confirm identity in biological and product samples.
GW501516 acts as an agonist at the peroxisome proliferator-activated receptor delta, a nuclear receptor that regulates gene expression. Activation shifts transcription toward genes involved in fatty acid uptake, oxidation, and energy expenditure. The compound does not bind the androgen receptor and therefore differs from anabolic steroids and SARMs. In rodent models, this metabolic shift has been linked to increased running endurance and reduced fat accumulation. The exact downstream pathways in humans remain incompletely characterized.
| Property | Value | Notes |
|---|---|---|
| Regulatory status | Prohibited in sport; not approved as medicine | Listed by WADA at all times. |
| Common synonyms | GW501516, GW-501516, endurobol | Cardarine is a colloquial name. |
| Typical analytical method | LC-MS/MS | Detects parent compound and metabolites. |
| Common test matrix | Urine | Blood and dried blood spots also possible. |
| Legal classification | Varies by country | Often treated as unapproved drug or research chemical. |
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.
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.
Laboratory detection of GW501516 commonly uses liquid chromatography coupled with tandem mass spectrometry. The method can identify the parent compound or its metabolites in urine and blood after sample cleanup. Protein precipitation, solid-phase extraction, or enzymatic hydrolysis may precede analysis, depending on the matrix. Reference standards are required for accurate quantification and confirmation. Because the compound is not approved, testing often occurs in anti-doping, forensic, or research settings rather than routine clinical care. Results are reported with limits of detection and quantification.
Stability of GW501516 depends on form, temperature, light exposure, and moisture. Solid reference material is typically stored frozen or refrigerated in a desiccator and protected from light. Solutions in organic solvents such as dimethyl sulfoxide are often kept frozen in aliquots to reduce freeze-thaw cycling. Aqueous solubility is low, so aqueous stock solutions can be difficult to prepare without cosolvents. Degradation may appear as changes in chromatographic purity or mass spectral signal. Stability studies are needed to establish shelf life for any specific preparation.
== Clinical significance == Mutations of the CELA1 gene were suspected to be associated with diffuse nonepidermolytic palmoplantar keratoderma (diffuse NEPPK). However the suspected sequence variant was fully functional and did not strongly associate with the disease. More recently, a specific mutation in the KRT6C gene has been linked to some cases of diffuse NEPPK. A possible polymorphism of the CELA1 gene coding this protein was found. On a secondary structure level, this polymorphism manifests itself in an excision of a short sequence of CELA1. The disappeared sequence carries the key amino acid residues Val-227 and Thr-239, which contribute to the substrate specificity of elastase I (highlighted in Figure 3), as well as five of the eight amino acids involved in the primary contact of the elafin(inhibitor)/elastase complex formation. These observations imply that the sequence variant might modify the substrate specificity of the enzyme and abolish the inhibitor binding capability. Though there were no obvious pathogenic epidermal abnormalities associated with the truncated ELA1 variant, it is possible that carriers of the polymorphism may be at greater risk of developing the common skin diseases such as psoriasis and eczema (genetic and histologic studies will be required to investigate the role of ELA1 in these common epidermal disorders.).
Flame ionization detector which uses ionizing flame to detect most hydrocarbon molecules Flame photometric detector which uses atomizing flame to get light emitted from specific elements to detect and quantify them Nitrogen Phosphorus Detector a thermionic detector with photometeric detection, sensitive specifically to nitrogen and phosphorus hydrocarbons Atomic-emission detector is a hyphenation between gas chromatography and atomic emission spectrophotometer for detection of elements. In all types of chromatography:
In November 1979, Gunther von Hagens applied for a German patent, proposing the idea of preserving animal and vegetable tissues permanently by synthetic resin impregnation. Since then, von Hagens has applied for further US patents regarding work on preserving biological tissues with polymers. With the success of his patents, von Hagens went on to form the Institute for Plastination in Heidelberg, Germany in 1993. The Institute for Plastination, along with von Hagens, made their first showing of plastinated bodies in Japan in 1995, which drew more than three million visitors. The institute maintains three international centres of plastination, in Germany (Heidelberg-Rohrbach), Kyrgyzstan, and China.
== Predictive aspects == In a longitudinal evaluation of the NHANES study, a large sample of the general US population, over 10 years, a reduced static disposition index (SPINA-DI) significantly predicted all-cause mortality.
On 1 July, the experiment was performed with fifty mice, half of whom received penicillin. All twenty-five of the control mice died within sixteen hours while all but one of the treated mice were alive ten days later. Over the following weeks they performed experiments with batches of 50 or 75 mice, but using different bacteria. They found that penicillin was also effective against staphylococci and gas gangrene. Florey reminded his staff that promising as their results were, a human being weighed 3,000 times as much as a mouse. The Oxford team reported their results in the 24 August 1940 issue of The Lancet, a prestigious medical journal, as "Penicillin as a Chemotherapeutic Agent" with names of the seven joint authors listed alphabetically. They concluded:
Sources: en.wikipedia.org
Simplified database access Client and server cache management Client-side code generation, especially for form widgets and validation Conversion from HTML to PDF Data retrieval from common enterprise systems such as Active Directory, LDAP, SMTP, POP, HTTP, FTP, Microsoft Exchange Server and common data formats such as RSS and Atom File indexing and searching service based on Apache Solr GUI administration Server, application, client, session, and request scopes XML parsing, querying (XPath), validation and transformation (XSLT) Server clustering Task scheduling Graphing and reporting Simplified file manipulation including raster graphics (and CAPTCHA) and zip archives (introduction of video manipulation is planned in a future release) Simplified web service implementation (with automated WSDL generation / transparent SOAP handling for both creating and consuming services - as an example, ASP.NET has no native equivalent for <CFINVOKE WEBSERVICE="http://host/tempconf.cfc?wsdl" METHOD="Celsius2Fahrenheit" TEMP="#tempc#" RETURNVARIABLE="tempf">) Other implementations of CFML offer similar or enhanced functionality, such as running in a .NET environment or image manipulation. The engine was written in C and featured, among other things, a built-in scripting language (CFScript), plugin modules written in Java, and a syntax very similar to HTML. The equivalent to an HTML element, a ColdFusion tag begins with the letters "CF" followed by a name that is indicative of what the tag is interpreted to, in HTML. E.g. <cfoutput> to begin the output of variables or other content.
Proteins are targeted for degradation by the proteasome with covalent modification of a lysine residue that requires the coordinated reactions of three enzymes. In the first step, a ubiquitin-activating enzyme (known as E1) hydrolyzes ATP and adenylylates a ubiquitin molecule. This is then transferred to E1's active-site cysteine residue in concert with the adenylylation of a second ubiquitin. This adenylylated ubiquitin is then transferred to a cysteine of a second enzyme, ubiquitin-conjugating enzyme (E2). In the last step, a member of a highly diverse class of enzymes known as ubiquitin ligases (E3) recognizes the specific protein to be ubiquitinated and catalyzes the transfer of ubiquitin from E2 to this target protein. A target protein must be labeled with at least four ubiquitin monomers (in the form of a polyubiquitin chain) before it is recognized by the proteasome lid. It is therefore the E3 that confers substrate specificity to this system. The number of E1, E2, and E3 proteins expressed depends on the organism and cell type, but there are many different E3 enzymes present in humans, indicating that there is a huge number of targets for the ubiquitin proteasome system. The ubiquitin protein itself is 76 amino acids long and was named due to its ubiquitous nature, as it has a highly conserved sequence and is found in all known eukaryotic organisms. The genes encoding ubiquitin in eukaryotes are arranged in tandem repeats, possibly due to the heavy transcription demands on these genes to produce enough ubiquitin for the cell.
==== Cell migration ==== Cell migration during embryonic development allows for the establishment of body axes, tissue formation, limb induction and several other processes. Wnt signaling helps mediate this process, particularly during convergent extension. Signaling from both the Wnt PCP pathway and canonical Wnt pathway is required for proper convergent extension during gastrulation. Convergent extension is further regulated by the Wnt/calcium pathway, which blocks convergent extension when activated. Wnt signaling also induces cell migration in later stages of development through the control of the migration behavior of neuroblasts, neural crest cells, myocytes, and tracheal cells. Wnt signaling is involved in another key migration process known as the epithelial-mesenchymal transition (EMT). This process allows epithelial cells to transform into mesenchymal cells so that they are no longer held in place at the laminin. It involves cadherin down-regulation so that cells can detach from laminin and migrate. Wnt signaling is an inducer of EMT, particularly in mammary development.
=== Hormonal factors === Sex hormones seem to influence humoral and cell-mediated immune response, with estrogen being considered one of the biggest factors responsible for sex-immunologic dimorphism. Estrogen deficiency appears to play a role in the development of Sjögren's disease. It has been hypothesized that androgen administration to the ocular surface may serve as an effective therapy for dry eyes.
Sources: en.wikipedia.org
Legal status varies by country. It is not approved as a medicine, and it is prohibited in sport. Some jurisdictions restrict import, sale, or possession.
Laboratories use liquid chromatography-tandem mass spectrometry to detect GW501516 and its metabolites. Urine is commonly tested, and testing can occur in and out of competition.
No, cardarine is not a SARM. It is a PPARδ agonist, which acts on a different receptor. The two classes are often confused in online discussions.
It targets PPARδ, a nuclear receptor involved in lipid and energy metabolism. It does not act primarily on androgen receptors. This distinction separates it from SARMs.