GW501516 raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
This page was last updated on 2026-08-01 and is reviewed periodically as new material appears.
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.
Early clinical research explored GW501516 for lipid disorders, obesity, and diabetes. Some short-term human studies reported changes in HDL cholesterol, LDL cholesterol, and triglycerides. The development program was discontinued after rodent studies showed dose-dependent tumor formation in multiple tissues, including liver, bladder, stomach, and skin. These findings raised concerns about long-term cancer risk in humans. Because human exposure data are limited, the clinical significance of the rodent tumors remains uncertain.
| 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.
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.
Cardarine is explicitly prohibited by the World Anti-Doping Agency under the class of PPARδ agonists. Its presence in urine or blood samples can be detected using mass spectrometry-based methods, often liquid chromatography-tandem mass spectrometry. Athletes who test positive may face sanctions, including bans from competition. The compound is also regulated as a prescription-only or unapproved drug in many countries. Enforcement varies by jurisdiction, and some regions treat it as a controlled substance. Online sales may occur despite these restrictions, creating quality and legal risks.
Laboratory detection of cardarine typically involves sample preparation followed by chromatographic separation and mass spectrometric identification. Urine is the most common matrix for anti-doping tests, though blood and hair have also been explored. Methods can target the parent compound or its metabolites, depending on the expected window of detection. Reference standards are required for accurate quantification. Matrix effects and dilution can influence results, so laboratories use internal standards and validation protocols. The exact detection window varies with dose, route, and individual metabolism.
A common misconception is that cardarine has been proven safe for human use. In reality, human clinical data are limited, and long-term animal studies have raised concerns about cancer. Another misconception is that it is a supplement or vitamin-like compound. It is a synthetic research chemical with no approved medical indication. Scientific discussion often focuses on its mechanism and detection rather than therapeutic use. Regulatory and anti-doping literature treats it primarily as a prohibited substance.
There are over 200 Clostridium species in the world that live in mundane places such as soil, water, dust, and even our digestive tracts. Some of these species produce harmful toxins such as botulinum toxin and tetanus toxin among others. Most Clostridium species that do have toxins typically have AB toxins with part of the toxin involved in cellular entry and the other element delivering a toxic cargo, that is often an enzyme into the cell. Clostridial toxins are widespread and are common causes of disease in humans and other organisms. Clostridioides difficile Toxin A and Toxin B are the two major toxins produced by Clostridioides difficile. Toxin A and toxin B are glucosyltransferases that cause the antibiotic-associated pseudomembranous colitis and severe diarrhea that characterize disease presentation of Clostridioides difficile infections. The binary toxin toxin CDT is also produced by some strains of C. difficile.
100. Tirzepatide. Drugs and Lactation Database (LactMed®) [Internet]. Bethesda (MD): National Institute of Child Health and Human Development; 2006–. 2026 Aug 15. Tirzepatide is usually undetectable in breastmilk with subcutaneous doses of up to 5 mg. Furthermore, absorption by the infant is unlikely because it is probably partially destroyed in the infant’s gastrointestinal tract and poorly absorbed orally. If a mother requires tirzepatide, it is not a reason to discontinue breastfeeding. Until more data become available, tirzepatide should be used with caution during breastfeeding, especially while nursing a newborn or preterm infant. Some experts recommend closely monitoring of infant growth and developmental milestones and the nutritional status of the lactating woman.[1]
89. Mymensingh Med J. 2026 Oct;35(4):1312-1316. Diagnosis of Rhinoentomophthoromycosis in a 55 Years Old Male: A Case Report. Shawrave SA(1), Zoheb SJM, Galib GI, Tanni RZ, Shawon MMR, Bhuiyan MJT. Author information: (1)Dr Shaharior Arafat Shawrave, Associate Professor, Department of ENT and Head Neck Surgery, Dhaka Medical College (DMC), Dhaka, Bangladesh; E-mail: shawrave77@gmail.com. Entomophthoromycosis is a chronic fungal infection characterized by a diverse range of manifestations, including subcutaneous, mucocutaneous and visceral infections. The majority of subcutaneous infections caused by entomophthoralean fungi are attributed to Basidiobolus spp, C. coronatus or C. incongruous. In this report, we present a case of rhinoentomophthoromycosis in a middle-aged, immunocompetent male, primarily affecting the nasopharynx. Initially, the diagnosis posed a dilemma, but it was ultimately confirmed through meticulous examination of microscopy and histopathology of the aspirate. The patient's response to antifungal therapy was favorable. We hereby provide a comprehensive account of this case and discuss the efficacy of Posaconazole in the treatment of rhinoentomophthoromycosis in a 55-year-old male patient with diabetes.
There is some covalent crosslinking within the triple helices and a variable amount of covalent crosslinking between tropocollagen helices forming well-organized aggregates (such as fibrils). Larger fibrillar bundles are formed with the aid of several different classes of proteins (including different collagen types), glycoproteins, and proteoglycans to form the different types of mature tissues from alternate combinations of the same key players. Collagen's insolubility was a barrier to the study of monomeric collagen until it was found that tropocollagen from young animals can be extracted because it is not yet fully crosslinked. However, advances in microscopy techniques (i.e. electron microscopy (EM) and atomic force microscopy (AFM)) and X-ray diffraction have enabled researchers to obtain increasingly detailed images of collagen structure in situ. These later advances are particularly important to better understanding the way in which collagen structure affects cell–cell and cell–matrix communication and how tissues are constructed in growth and repair and changed in development and disease. For example, using AFM–based nanoindentation it has been shown that a single collagen fibril is a heterogeneous material along its axial direction with significantly different mechanical properties in its gap and overlap regions, correlating with its different molecular organizations in these two regions. Collagen fibrils/aggregates are arranged in different combinations and concentrations in various tissues to provide varying tissue properties.
=== Safety concerns === Hydrolyzed collagen, like gelatin, is made from animal by-products from the meat industry or sometimes animal carcasses removed and cleared by knackers, including skin, bones, and connective tissue. In 1997, the U.S. Food and Drug Administration (FDA), with support from the TSE (transmissible spongiform encephalopathy) Advisory Committee, began monitoring the potential risk of transmitting animal diseases, especially bovine spongiform encephalopathy (BSE), commonly known as mad cow disease. An FDA study from that year stated: "... steps such as heat, alkaline treatment, and filtration could be effective in reducing the level of contaminating TSE agents; however, scientific evidence is insufficient at this time to demonstrate that these treatments would effectively remove the BSE infectious agent if present in the source material." On 18 March 2016, the FDA finalized three previously issued interim final rules designed to further reduce the potential risk of BSE in human food. The final rule clarified that "gelatin is not considered a prohibited cattle material if it is manufactured using the customary industry processes specified." The Scientific Steering Committee (SSC) of the European Union in 2003 stated that the risk associated with bovine bone gelatin is very low or zero.
Sources: en.wikipedia.org
In January 2021, the aromaticity has been observed in a large metal cluster anion consisting of 12 bismuth atoms stabilised by a center thorium cation. This compound was shown to be surprisingly stable, unlike many previous known aromatic metal clusters.
== History == Insulin was discovered by Sir Frederick G Banting, Charles H Best, and JJR Macleod from the University of Toronto in 1921 as an injectable agent. German researchers first introduced the idea of inhalable insulin in 1924. Years of failure followed until scientists realized they might be able to use new technologies to turn insulin into a concentrated powder with particles sized for inhalation. In the 1980s Nektar Therapeutics, based on work by A. Carl Leopold on vitrifying proteins, developed technology to make insulin into small particles, technology then licensed to Pfizer. Alkermes developed a delivery device that they licensed to Eli Lilly and Company. Once concrete methods were developed, human tests began in the late 1990s. In January 2006, the U.S. Food and Drug Administration (FDA) approved the use of Exubera, a form of inhalable insulin developed by Pfizer. It was approved in the UK in August 2006 but reimbursed by the National Health Service only for people who had problems with needles. It was not reimbursed by any U.S. insurer. A 2007 systematic review concluded that the inhaled hexameric insulin (Exubera) "appears to be as effective, but no better than injected short-acting insulin. The additional cost is so much more that it is unlikely to be cost-effective." In 2007, Pfizer announced that it would no longer manufacture or market Exubera. According to Chairman and CEO Jeffrey Kindler this was because Exubera "failed to gain acceptance among patients and physicians".
=== Mechanistic vs. empirical models === A main difference in evolutionary models is how many parameters are estimated every time for the data set under consideration and how many of them are estimated once on a large data set. Mechanistic models describe all substitutions as a function of a number of parameters which are estimated for every data set analyzed, preferably using maximum likelihood. This has the advantage that the model can be adjusted to the particularities of a specific data set (e.g. different composition biases in DNA). Problems can arise when too many parameters are used, particularly if they can compensate for each other (this can lead to non-identifiability). Then it is often the case that the data set is too small to yield enough information to estimate all parameters accurately. Empirical models are created by estimating many parameters (typically all entries of the rate matrix as well as the character frequencies, see the GTR model above) from a large data set. These parameters are then fixed and will be reused for every data set. This has the advantage that those parameters can be estimated more accurately. Normally, it is not possible to estimate all entries of the substitution matrix from the current data set only. On the downside, the parameters estimated from the training data might be too generic and therefore have a poor fit to any particular dataset. A potential solution for that problem is to estimate some parameters from the data using maximum likelihood (or some other method).
On the morning of 8 September, representatives of the Fatherland Front - Kimon Georgiev, Nikola Petkov, Dimitar Neykov, Kiril Dramaliev and Dimo Kazasov - met with the Prime Minister, protesting the dispersal of opposition demonstrations in the previous days and demanding that rallies be allowed in the major cities. Kimon Georgiev hosted a meeting of the Fatherland Front's National Committee at 4 p.m. on 8 September. The government's composition was settled upon, and its policy text is approved. The composition of the future government and the new regents were specified at a meeting between Kimon Georgiev, Dobri Terpeshev, Nikola Petkov and Damyan Velchev at Georgiev's home at 4 pm on 8 September. It was agreed that the cabinet would include four representatives each of the BRP, Zveno and BZNS-Pladne, two of the BRSD and two independents, and that the prime minister would be Kimon Georgiev, a decision agreed with Soviet dictator Joseph Stalin. Georgiev spent the night of the coup with Damyan Velchev, Nikola Petkov, and Traicho Dobroslavsky at the home of Yanko Antonov near the Eagles Bridge - he was a neighbor of Peter Vranchev, in whose apartment the Communist leaders - Dobri Terpeshev, Anton Yugov, Georgi Chankov, Angel Tsanev, and Katya Avramova were at the time. The coup began at 2 a.m. on 9 September with the seizure of the War Ministry building. War Minister Ivan Marinov sided with the coup and issued the appropriate orders to the First Infantry Division and the School for Reserve Officers.
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.