A practical reference on anti-doping: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
This page was last updated on 2025-10-10 and is reviewed periodically as new material appears.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Solubility | Soluble in dimethyl sulfoxide and some organic solvents; practically insoluble in water | Solvent choice affects laboratory handling |
| Typical storage | -20 °C, desiccated, protected from light | Common condition for research samples |
| Analytical method | Liquid chromatography–tandem mass spectrometry (LC-MS/MS) | Used for identification and quantification in biological or product samples |
| Common synonyms | GW501516, GW-501516, GSK-516, Endurobol | Names found in research and anti-doping literature |
| Regulatory status | Unapproved therapeutic; prohibited in competitive sport | Status can vary by country and context |
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.
Analytical laboratories typically identify cardarine and its metabolites using liquid chromatography-tandem mass spectrometry. Urine is a common matrix in anti-doping testing, while blood and tissue may be used in research settings. Detection windows depend on the assay, the sample matrix, and the compound's metabolism. Because cardarine is extensively metabolized, laboratories often target specific metabolites to improve sensitivity and confirmation. Reference standards are required for reliable quantification. Method validation includes checks for selectivity, linearity, and carryover.
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 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.
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.
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.
== Abstracting and indexing == The journal is abstracted and indexed in Chemical Abstracts, Current Contents/Clinical Medicine, Index Medicus/MEDLINE/PubMed, Science Citation Index Expanded, and Scopus. According to the Journal Citation Reports, the journal has a 2015 impact factor of 1.224.
==== Absorption ==== The oral bioavailability of atenolol is approximately 50 to 60%. The absorption of atenolol with oral administration is rapid and consistent but is incomplete. About 50% of an oral dose of atenolol is absorbed from the intestines, with the rest excreted in feces. Maximal concentrations of atenolol occur 2 to 4 hours following an oral dose, whereas peak concentrations occur within 5 minutes with intravenous administration. The pharmacokinetic profile of atenolol results in it having relatively consistent plasma drug levels with about 4-fold variation between individuals.
== Pharmacology == The pharmacodynamic profile of deupsilocin, including its interactions with serotonin receptors and its effects in animals, is similar to that of psilocin. As with psilocin, deupsilocin is a potent agonist of the serotonin 5-HT2A receptor and produces psychedelic-like effects in animals. However, it was developed to have improved pharmacokinetic properties compared to psilocybin, including reduced variability in circulating levels, a faster onset of action, and a shorter duration. In humans, deupsilocin has been reported to have 2.2-fold higher peak levels and 3.5-fold higher area-under-the-curve (AUC) levels than psilocybin at equivalent doses. It is said to have a rapid onset of less than 15 minutes and a duration of 4 to 6 hours.
residents determined to be at the greatest risk of exposure to counterfeit products through personal prescription drug importation, are aged greater than 45 years, reside in the south or west regions of the U.S., are of Hispanic ethnicity, college educated, poor or near poor poverty status, lacking U.S. citizenship, traveling to developing countries, lacking health insurance, managing high family out-of-pocket medical costs, having trouble finding a healthcare provider, self-reporting fair or poor health status, filling a prescription on the Internet, and using online chat groups to learn about health. Recent evidence suggests that provision of health insurance coverage may effectively reduce importation and the subsequent risk of exposure to counterfeit medicines, especially among particular subpopulations.
Sources: en.wikipedia.org
=== Covalent catalysis === Covalent catalysis involves the substrate forming a transient covalent bond with residues in the enzyme active site or with a cofactor. This adds an additional covalent intermediate to the reaction, and helps to reduce the energy of later transition states of the reaction. The covalent bond must, at a later stage in the reaction, be broken to regenerate the enzyme. This mechanism is utilised by the catalytic triad of enzymes such as proteases like chymotrypsin and trypsin, where an acyl-enzyme intermediate is formed. An alternative mechanism is schiff base formation using the free amine from a lysine residue, as seen in the enzyme aldolase during glycolysis. Some enzymes utilize non-amino acid cofactors such as pyridoxal phosphate (PLP) or thiamine pyrophosphate (TPP) to form covalent intermediates with reactant molecules. Such covalent intermediates function to reduce the energy of later transition states, similar to how covalent intermediates formed with active site amino acid residues allow stabilization, but the capabilities of cofactors allow enzymes to carryout reactions that amino acid side residues alone could not. Enzymes utilizing such cofactors include the PLP-dependent enzyme aspartate transaminase and the TPP-dependent enzyme pyruvate dehydrogenase. Rather than lowering the activation energy for a reaction pathway, covalent catalysis provides an alternative pathway for the reaction (via to the covalent intermediate) and so is distinct from true catalysis.
=== Advantages in animals === Balanced anesthesia has various advantages in veterinary cases: In certain circumstances it is considerably cheaper than the usual anesthesia. Secondly, it can reduce the death rate. Furthermore, it offers more stable operating conditions for veterinarians. It also increase animal safety and comfort. Balanced anesthesia can make patients calm by using drugs such as: medetomidine, diazepam or midazolam, and acepromazine. Keeping patients calm prior to surgery can avoid the unpredictable consequences of stress, such as tachypnea, hypertension and tachycardia which may be harmful to the anesthetized patients. In addition, anxiety and stress may cause the nociceptive pain. The balanced anesthesia therefore may therefore decrease those possible complications. Another advantage of using balanced anesthesia is that it can decrease the chance of adverse effects. All medicines may have adverse effect on patients; some serious adverse effects of anesthesia may be caused by inhalational anesthetic, although in general these medicines are highly safe and useful. Using the correct amount of balanced anesthetic agents, the adverse effects can be reduced to some extent. Balanced anesthesia can also minimize the pain patients suffer. Pain may delay wound healing, decrease appetite, and even result in death. Using the proper amount of analgesics can reduce the amount of inhalant anesthetics required and help patients reduce the pain.
First day: 1000 mg; the body clears 100 mg, leaving 900 mg. On the second day, the patient takes 100 mg, bringing the level back to 1000 mg; the body clears 100 mg overnight, still leaving 900 mg, and so forth.
Sources: en.wikipedia.org
== See also == State Sponsors of Terrorism (U.S. list) Specially Designated Nationals and Blocked Persons List United States sanctions on Bangladesh Caesar Syria Civilian Protection Act Rogue state Economic sanctions against the United States Permanent normal trade relations Arms Export Control Act Criticism of United States foreign policy European Union sanctions United Kingdom sanctions United States foreign adversaries
The UPMC Rooney Sports Complex is a multipurpose, multisport training, sports science, and sports medical complex located along the shore of the Monongahela River in Pittsburgh and is unique in that it combines training facilities for the University of Pittsburgh football team and the Pittsburgh Steelers NFL team in one location with an academically based sports science and medicine program. The complex consists of four centers which include the Center for Sports Medicine, Sports Training Center, Indoor Training Center, and the Fitness and Conditioning Center.
=== Wound healing in animals === A series of animal experiments established pronounced wound healing activity of GHK-Cu. In the dermal wounds of rabbits GHK-Cu facilitated wound healing, causing better wound contraction, faster development of granular tissue and improved angiogenesis. It also elevated the level of antioxidant enzymes. GHK-Cu has been found to induce a systemic enhancement of healing in rats, mice, and pigs; that is, the GHK-Cu peptide injected in one area of the body (such as the thigh muscles) improved healing at distant body areas (such as the ears). These treatments strongly increased healing parameters such as collagen production, angiogenesis, and wound closure in both wound chambers and full thickness wounds. In one study, full‐thickness wounds of 6 millimeters in diameter were created in an ischemic skin flap on the backs of rats, and for 13 days the wound sites were then treated daily with topical GHK-Cu or topical hydroxypropyl methylcellulose vehicle, or given no treatment. At the end of the study, the wound size had decreased by 64.5% in the GHK group; by 45.6% in the vehicle-treated group; and by 28.2% in the control group. The difference between the GHK group's wounds and those of the control group was significant, and was accompanied by significantly lower levels of tumor necrosis factor alpha and elastin-degrading matrix metalloproteinases. Biotinylated GHK-Cu was incorporated into a collagen membrane, which was used as a wound dressing.
Sources: en.wikipedia.org
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.
No. It is not an anabolic-androgenic steroid; it is a synthetic PPARδ agonist. Because it is banned in sport, it is sometimes grouped with doping agents even though its chemical class differs from steroids.
Human data are limited and development was discontinued, so major effects and long-term risks are not well characterized. Some early studies examined metabolic markers, but they do not provide a basis for unsupervised use.
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.