Anti-doping testing comes up often in conversation and rarely with the context attached. Here we lay out the basics in order, then work through the practical considerations.
Updated 2026-04-05. Numbers and descriptions here follow the published literature rather than marketing material.
Regulatory treatment varies, but cardarine is not approved as a medicine. Sports authorities list GW501516 as a prohibited substance, and it is banned at all times under the World Anti-Doping Agency code. Many countries restrict sales for human consumption, while online vendors market it as a research chemical. Such products may lack purity data, and their actual contents can differ from the label. Purchasing or possessing cardarine may carry legal consequences depending on jurisdiction. The compound is not a dietary supplement ingredient in regulated markets.
Clinical development stopped after rodent studies showed tumors at multiple sites. Whether those findings predict human cancer risk remains an open question, but they led sponsors to discontinue programs. Human safety data are limited to small, short-term studies that were not designed to assess cancer risk. Reported effects in those studies included changes in blood lipids, but the evidence is insufficient for medical use. Long-term consequences of nonmedical use are not well characterized. Questions about dose, duration, and individual susceptibility remain unresolved.
Cardarine is a common name for GW501516, an investigational compound developed in the 1990s for metabolic conditions. It acts as an agonist at peroxisome proliferator-activated receptor delta, a nuclear receptor involved in lipid and energy metabolism. The compound is frequently mislabeled as a selective androgen receptor modulator, or SARM, but its molecular target is different. GW501516 reached early clinical testing before development was discontinued. It has no approved therapeutic use in any country. The name cardarine is not a formal international nonproprietary name.
In the fitness and bodybuilding literature, cardarine is frequently discussed as an endurance agent or fat-loss compound, although such claims are not supported by robust clinical evidence. Online descriptions often mix animal data, user anecdotes, and marketing language. Researchers who study PPARδ agonists distinguish between receptor activation in controlled experiments and unsupervised use of unverified products. The latter introduces unknown purity, dose, and interactions, making reported experiences difficult to interpret scientifically.
GW501516 acts as an agonist at peroxisome proliferator-activated receptor delta, a nuclear receptor involved in transcription of genes related to lipid handling and energy use. Activation of PPARδ can shift skeletal muscle toward greater fatty acid oxidation in animal models, which is one reason it drew interest for metabolic disease and exercise research. The exact downstream effects depend on tissue, species, dose, and duration. Human data are sparse, so many proposed benefits remain hypotheses rather than established clinical outcomes.
Laboratory studies have examined GW501516 in cell cultures and rodents for conditions such as dyslipidemia, insulin resistance, and obesity. Some trials in humans were initiated, but development was discontinued after preclinical findings raised concerns about cancer in certain models. Those findings do not prove that the compound causes cancer in people, but they contributed to regulatory caution. Later reviews often describe the evidence as preliminary and insufficient for assessing long-term safety.
| Property | Value | Notes |
|---|---|---|
| Common synonyms | GW501516; GW-1516; endurobol | GW501516 is the research code |
| Drug class | PPARδ agonist | Not a selective androgen receptor modulator |
| Molecular formula | C21H18F3NO3S2 | Established chemical formula |
| Molar mass | 453.5 g/mol | Calculated from the formula |
| Regulatory status | Prohibited in sport; not approved as medicine | Status varies by country |
A persistent misconception is that cardarine is a fat-burning drug or a safe alternative to anabolic steroids. No approved therapeutic product exists, and human safety data are limited. The tumor findings in rodents remain a central concern in scientific reviews. Products sold online may contain inaccurate labels, impurities, or different compounds entirely, which complicates any assessment of effects. Independent testing of such products has reported frequent mislabeling. For these reasons, discussions in the literature emphasize risks and unknowns rather than benefits.
Cardarine is not approved for human therapeutic use in any major jurisdiction. It appears on the World Anti-Doping Agency Prohibited List as a PPARδ agonist within the hormone and metabolic modulators category. Sports organizations test for it because it has been detected in athlete samples and seized products. Regulatory actions against marketed research chemical versions have occurred in several countries, though enforcement varies. Availability through unregulated channels complicates oversight.
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.
Because cardarine is not an approved medicine, no pharmacopeial monograph defines its identity, purity, or storage requirements. Laboratories typically rely on in-house methods and reference standards when testing materials labeled as GW501516. Certificates of analysis may report purity and identity for a specific batch, but their scope varies and they do not guarantee safety or legal status. Independent verification can include high-performance liquid chromatography, mass spectrometry, nuclear magnetic resonance, and elemental analysis. The distinction between research chemical labeling and human use is significant because quality standards and oversight differ.
Cardarine can be detected in biological samples and product materials using liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). The method separates compounds by chromatography and identifies them by mass-to-charge transitions, allowing low-level detection in urine or blood. Sample preparation often involves enzymatic hydrolysis, solid-phase extraction, or protein precipitation. Certified reference materials and isotope-labeled internal standards improve quantification. Detection windows depend on metabolism, matrix, and assay sensitivity, so no single universal window applies.
Regulatory treatment of cardarine differs by context and jurisdiction. In competitive sport, the World Anti-Doping Agency lists PPARδ agonists, including GW501516, as prohibited at all times. Outside sport, it lacks approval as a prescription medicine in major drug markets, and products sold for human consumption may be treated as unapproved drugs. Some countries also restrict importation or sale through general consumer protection and medicines laws. These classifications affect availability, testing, and legal risk without establishing therapeutic value.
=== Viral-mediated delivery === The gene silencing effects of transfected, designed siRNA are generally transient, but this difficulty can be overcome through an RNAi approach. Delivering this siRNA from DNA templates can be done through several recombinant viral vectors based on retrovirus, adeno-associated virus, adenovirus, and lentivirus. As of primary research work in 2006, the latter virus was the most efficient for stable delivery of siRNA to target cells, as it could be used to transduce nondividing cells, as well as to directly target the nucleus. These specific viral vectors have been synthesized to effectively facilitate siRNA that is not viable for transfection into cells. In some cases synthetic viral vectors can integrate siRNA into the cell genome, which allows for stable expression of siRNA and long-term gene knockdown. This technique is advantageous because it is an in vivo method, and can be effective for difficult to transfect cells. However, problems arise because it can trigger antiviral responses in some cell types, leading to mutagenic and immunogenic effects. This method has been shown to have potential for use in gene silencing of the central nervous system genes, e.g., in the treatment of Huntington's disease.
== Responses to foods == Big gastrin is one form of gastrin predominate in circulation after a meal, another major form is called little gastrin (G17). Both forms of gastrin have been isolated from human gastrinoma and hog antral mucosa. G34 is carboxy-amidated and can be sulphated or unsulphated at the tyrosine residues. Binding of gastrin to the receptors in stomach can cause the secretion of hydrochloric acids (HCl), the gastric acid. Duodenal ulcer patients tend to have higher than normal basal and maximal rate of gastric acid secretion, while gastric ulcer patients have lower than normal basal and maximal of gastric acid output. Comparing G34 in normal and peptic ulcer subjects by using radioimmunoassay in fasting serum and after feeding, basal G34 was found similar in normal and duodenal ulcer but raised in gastric ulcer before meal. After a meal, the concentration of G34 was increased in both duodenal ulcer patients and gastric ulcer patients, which significantly higher than normal people.
== Disease cycle == P. expansum infects a fruit via wounds through which the conidia are able to enter. Usually, puncturing, bruising, and limb rubs occur during harvesting, packaging, and processing of the fruit, all of which provide sites through which spores can enter the fruit. Conidia can be found in soil, decaying debris, and tree bark, and can survive cold temperatures. Conidia may be isolated from the air of the orchard and packaging house, on the walls of the packaging houses, and from the water and fungicide solution into which harvested fruits are dunked before packaging or storage. Exposure to conidia at any step of growth, harvesting, processing, shipping, and storage can lead to inoculation and disease. Conidia that have gained access via a wound can germinate to form a germ tube. This germ tube will continue to grow as hyphae, which colonize the fruit, killing fruit cells in an expanding infection. If the fungus has colonized the fruit with mycelium, the formation of conidiophores occurs on the surface or subsurface of the hyphae. The conidiophores are mostly smooth-walled terverticillate penicilli. A terverticillate pencilii has multiple branch points below the phialides, the cells that the conidia are attached to. However, at times, the penicilli may be rough or biverticillate (only two levels of branching). The phialides are packed close together with nearly a cylindrical shape. The conidia are dry, smooth, elliptical, and "dull-green" in color and are often disseminated by wind currents. Sexual reproduction has not been observed in nature for P. expansum.
duplication The production of a second copy of part or all of a nucleotide sequence or amino acid sequence, either naturally or artificially, and the retention of both copies; especially when both the copy and the original sequence are retained in situ within the same molecule, often but not necessarily adjacent to each other. See also gene duplication, chromosomal duplication, and repeat.
==== Gene expression ==== Studies have shown that morphine can alter the expression of several genes. A single injection of morphine has been shown to alter the expression of two major groups of genes, for proteins involved in mitochondrial respiration and for cytoskeleton-related proteins.
Sources: en.wikipedia.org
Antagomirs were first developed to target miR-122, a microRNA that was abundant and specific to the liver, and this discovery has led to the development of other antagomirs that can pair with specific microRNAs present in the tumor microenvironment or in the cancer cells. A microRNA mimic to miR-655 was found to suppress EMT through the targeting of EMT inducing transcription factor ZEB1 and TGF-β receptor 2 in a pancreatic cancer cell line. Overexpression of the miR-655 mimic in the Panc1 cancer cell line upregulated the expression of E-cadherin and suppressed the migration and invasion of mesenchymal-like cancer cells. The use of microRNA mimics to suppress EMT has expanded to other cancer cell lines and holds potential for clinical drug development. However, microRNA mimics and antagomirs suffer from a lack of stability in vivo and lack an accurate delivery system to target these molecules to the tumor cells or tissue for treatment. Improvements to antagomir and microRNA mimic stability through chemical modifications such as locked nucleic acid (LNA) oligonucleotides or peptide nucleic acids (PNA) can prevent the fast clearing of these small molecules by RNases. Delivery of antagomirs and microRNA mimics into cells by enclosing these molecules in liposome-nanoparticles has generated interest however liposome structures suffer from their own drawbacks that will need to be overcome for their effective use as a drug delivery mechanism. These drawbacks of liposome-nanoparticles include nonspecific uptake by cells and induction of immune responses.
== Benefits == SASP can aid in signaling to immune cells for senescent cell clearance, with specific SASP factors secreted by senescent cells attracting and activating different components of both the innate and adaptive immune system. The SASP cytokine CCL2 (MCP1) recruits macrophages to remove cancer cells. Although transient expression of SASP can recruit immune system cells to eliminate cancer cells as well as senescent cells, chronic SASP promotes cancer. Senescent hematopoietic stem cells produce a SASP that induces an M1 polarization of macrophages which kills the senescent cells in a p53-dependent process. Autophagy is upregulated to promote survival. SASP factors can maintain senescent cells in their senescent state of growth arrest, thereby preventing cancerous transformation. Additionally, SASP secreted by cells that have become senescent because of stresses can induce senescence in adjoining cells subject to the same stresses, thereby reducing cancer risk. SASP can play a beneficial role by promoting wound healing. SASP may play a role in tissue regeneration by signaling for senescent cell clearance by immune cells, allowing progenitor cells to repopulate tissue. In development, SASP also may be used to signal for senescent cell clearance to aid tissue remodeling. The ability of SASP to clear senescent cells and regenerate damaged tissue declines with age. In contrast to the persistent character of SASP in the chronic inflammation of multiple age-related diseases, beneficial SASP in wound healing is transitory.
That the notochord evolved de novo in chordates by combining development programs in new ways. That the notochord derives from a homologous muscular structure, the axochord, that was present in annelid-like ancestors of the chordates. Supported by gene expression patterns and identification of said muscular structures in various inveterates, but cannot fully rule out the possibility of homoplasy. Deciding between these two scenarios (or possibly another yet to be proposed) should be facilitated by much more thorough studies of gene regulatory networks in a wide spectrum of animals.
=== Other drugs === Certain medications can decrease the absorption of orally consumed vitamin B12, including colchicine, extended-release potassium products, and antibiotics such as gentamicin, neomycin and tobramycin. Anti-seizure medications phenobarbital, pregabalin, primidone and topiramate are associated with lower than normal serum vitamin concentration. However, serum levels were higher in people prescribed valproate. In addition, certain drugs may interfere with laboratory tests for the vitamin, such as amoxicillin, erythromycin, methotrexate and pyrimethamine.
These actions, including weak DAT inhibition combined with secondary catecholaminergic, orexinergic, glutamatergic, and GABAergic modulation, are thought to underlie modafinil's ability to promote wakefulness and cognitive function with a lower risk of euphoria and abuse than traditional amphetamine-like psychostimulants. From laboratory research, modafinil has little to no affinity for serotonin or norepinephrine transporters and does not directly interact with these systems. However, studies have shown that elevated concentrations of norepinephrine and serotonin can occur as an indirect effect following modafinil administration due to increased extracellular dopamine activity. Unlike traditional psychostimulant drugs, such as cocaine or amphetamine, modafinil shows low potential for causing euphoria due to differences in how it interacts with dopamine transporters at a cellular level. In addition to its influence on dopaminergic pathways, modafinil may impact other neurotransmitter systems, such as orexin (hypocretin) and histamine. Orexinergic and histaminergic neurons are involved in promoting wakefulness and regulating arousal states. Modafinil may increase signaling within hypothalamic orexin and histamine pathways, potentially contributing to its wake-promoting effects. In animal models, modafinil-induced increases in hypothalamic histamine release require intact orexinergic neurons. The wake-promoting effects of modafinil do not appear to depend on the orexin system.
Sources: en.wikipedia.org
No. Cardarine is GW501516, a PPARδ agonist, while SARMs act on androgen receptors. The two classes are often grouped in informal discussions despite different mechanisms.
No. It has no approved medical indication in any country. Regulatory agencies have not cleared it for treatment or prevention of any condition.
Early clinical work stopped after rodent carcinogenicity findings. Those animal results raised concerns about long-term human risk, although direct human evidence is lacking. The human relevance of the tumors remains an open scientific question.
It binds and activates PPARδ, a nuclear receptor that influences gene expression related to fatty acid metabolism and energy balance. This mechanism has been studied mainly in animals and cell models, not established as a safe human therapy.