Everything below concerns PPARδ agonist. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Updated 2026-01-25. Numbers and descriptions here follow the published literature rather than marketing material.
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.
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.
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.
| 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. |
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.
Cardarine is prohibited in competitive sport under the World Anti-Doping Agency code, where it is classified as a metabolic modulator. It is not approved as a prescription medicine in the United States, European Union, or other major markets. Regulatory action has focused on its presence in sports and in products marketed as research chemicals. Because it has no accepted medical indication, supply is often unregulated. This status creates legal and safety uncertainties for anyone who encounters the substance.
Anti-doping laboratories detect GW501516 and its metabolites using liquid chromatography-tandem mass spectrometry. Urine is the most common matrix, though blood and dried blood spots may also be used in some programs. Detection depends on factors such as dose, timing, metabolism, and the sensitivity of the assay. Published methods describe limits of detection in the low nanogram per milliliter range for related compounds. Exact detection windows are not fixed for all situations and remain an area of ongoing study.
Products sold as cardarine have been found to contain incorrect compounds, variable amounts, or no active ingredient at all. Independent testing is required to verify identity and purity. Common analytical approaches include high-performance liquid chromatography, mass spectrometry, and nuclear magnetic resonance for structural confirmation. These methods can distinguish GW501516 from related PPAR agonists and from unrelated steroids. For regulators and researchers, such verification is central to interpreting both biological results and adverse event reports.
== Causes == Postinflammatory hyperpigmentation develops after the original symptoms of an inflammatory skin condition disappear. Common triggers include acne lesions, cuts, burns, or skin conditions like eczema. Additionally, UV sun exposure and sunburn are involved in the development, darkening, and expansion of hyperpigmented skin lesions. Some medical procedures performed on the skin can cause an inflammatory reaction, which may lead to hyperpigmentation, even if the inflammation itself is temporary. The exact pathogenesis of PIH is poorly understood. It is known to be driven by cytokine-mediated paracrine interactions between keratinocytes and melanocytes, eventually stimulating the melanocytes to dramatically increase production of melanin, which then deposits in the skin.
== Biological function == NADPH oxidases (NOXes) are one of the major sources of cellular reactive oxygen species (ROS), and they still are the focus of extensive research interest due to their exclusive function in producing ROS under normal physiological conditions. The NADPH oxidase complex is dormant under normal circumstances but is activated to assemble in the membranes during respiratory burst. The activated NADPH oxidase generates superoxide which has roles in animal immune response and plant signalling. Superoxide can be produced in phagosomes which have ingested bacteria and fungi, or it can be produced outside of the cell. In macrophages, superoxide kills bacteria and fungi by mechanisms that are not yet fully understood. Superoxide spontaneously dismutates to form peroxide which is then protonated to produce hydrogen peroxide. Opinions are polarised as to how the oxidase kills microbes in neutrophils. On the one hand it is thought that hydrogen peroxide acts as substrate for myeloperoxidase to produce hypochlorous acid. It may also inactivate critical metabolic enzymes, initiate lipid peroxidation, damage iron-sulphur clusters, and liberate redox-active iron, which allows the generation of indiscriminate oxidants such as the hydroxyl radical.
== Causes == Damage from mechanical stress with insufficient self-repair by joints is believed to be the primary cause of osteoarthritis. Sources of this stress may include misalignments of bones caused by congenital or pathogenic causes; mechanical injury; excess body weight; loss of strength in the muscles supporting a joint; and impairment of peripheral nerves, leading to sudden or uncoordinated movements. The risk of osteoarthritis increases with aging, history of joint injury, or family history of osteoarthritis. However exercise, including running in the absence of injury, has not been found to increase the risk of knee osteoarthritis. Nor has cracking one's knuckles been found to play a role.
Sources: en.wikipedia.org
== Animal studies == Because of its significant role in the transportation of organic anion molecules and recent association with multiple illnesses including Alzheimer's disease (AD), the ABCC1 protein has become a potential drug target. In ABBC1 knockout mice, β-amyloid clearance is much lower than in wild-type mice that expressed the gene. Furthermore, in mouse models of AD, treatment with thiethylperazine, a drug that activates ABBC1, increases β-amyloid clearance and decreases in the amount of β-amyloid found in the brains. St. John's wort, a substance containing the chemical hyperforin, has also been shown to have a positive effect on activity levels of ABCC1. In a study of the effects of St. John's wort on APP-tg mice, an extract of St. John's wort that contained decreased levels of hyperforin increased the activity of ABCC1 by 70 percent and led to decreased amounts of β-amyloid in the brain and increased cognitive function in the mice.
== Pharmacology == Medazepam acts as a prodrug to nordazepam. Benzodiazepine drugs including medazepam increase the inhibitory processes in the cerebral cortex by allosteric modulation of the GABA receptor. Benzodiazepines may also act via micromolar benzodiazepine-binding sites as Ca2+ channel blockers and significantly inhibited depolarization-sensitive calcium uptake in experiments with cell components from rat brains. This has been conjectured as a mechanism for high dose effects against seizures in a study. It has major active benzodiazepine metabolites, which gives it a more prolonged therapeutic effect after administration.
An inhibitor cystine knot (also known as ICK or Knottin) is a protein structural motif containing three disulfide bridges. Knottins are one of three folds in the cystine knot motif; the other closely related knots are the growth factor cystine knot (GFCK) and the cyclic cystine knot (CCK; cyclotide). Types include a) cyclic mobius, b) cyclic bracelet and c) acyclic inhibitor knottins. Cystine knot motifs are found frequently in nature in a plethora of plants, animals, and fungi and serve diverse functions from appetite suppression to anti-fungal activity. Along with the sections of polypeptide between them, two disulfides form a loop through which the third disulfide bond (linking the third and sixth cysteines in the sequence) passes, forming a knot. The motif is common in invertebrate toxins such as those from arachnids and molluscs. The motif is also found in some inhibitor proteins found in plants, but the plant and animal motifs are thought to be a product of convergent evolution. The ICK motif is a very stable protein structure which is resistant to heat denaturation and proteolysis. CK peptide components of venoms target voltage-gated ion channels but members of the family also act as antibacterial and haemolytic agents. Plant ICK proteins are often protease inhibitors. Knottins have high stability to pH, heat, and enzymes. Because of their stability and their favorable pharmacodynamic properties, knottins are becoming increasingly popular as protein engineering scaffolds.
Sources: en.wikipedia.org
Biotechnology has applications in four major industrial areas, including health care (medical), crop production and agriculture, non-food (industrial) uses of crops and other products (e.g., biodegradable plastics, vegetable oil, biofuels), and environmental uses. For example, one application of biotechnology is the directed use of microorganisms for the manufacture of organic products (examples include beer and milk products). Another example is using naturally present bacteria by the mining industry in bioleaching. Biotechnology is also used to recycle, treat waste, clean up sites contaminated by industrial activities (bioremediation), and also to produce biological weapons. A series of derived terms have been coined to identify several branches of biotechnology, for example:
Overall, the attenuation of solar UV at wavelengths that damage DNA by the ozone layer allows life to exist on the planet's surface outside of the ocean. All air entering the stratosphere must pass through the tropopause, the temperature minimum that divides the troposphere and stratosphere. The rising air is literally freeze-dried; the stratosphere is a very dry place. The top of the stratosphere is called the stratopause, above which the temperature decreases with height.
=== Cardiac studies === Itopride belongs to the same benzamide group as cisapride, a drug found to affect QT interval and possibly predispose those using it to cardiac arrhythmias. However, itopride does not have any adverse effect on the QT interval. Later, in a study conducted with healthy adult volunteers, itopride was shown as unlikely to cause cardiac arrhythmias or ECG changes in part to the lack of significant interaction and metabolism via the cytochrome P450 enzyme pathway, unlike cisapride and mosapride, as it is metabolized by a different enzyme set. New molecular studies on guinea pig ventricular myocytes also supported the cardiac safety profile of itopride, as it did not affect certain potassium mechanisms that may have been affected by cisapride or mosapride. Moreover, itopride has no affinity for the 5-HT4 receptors, unlike other benzamides such as cisapride and mosapride, which are 5-HT4 agonists. The affinity of cisapride for 5-HT4 receptors in the heart has been implicated in the undesirable cardiac effects of cisapride itself. The conclusion of this study revealed that itopride is devoid of any abnormal effect on QT interval. Therefore, it may be possible that itopride could be considered as a better and certainly safer prokinetic agent than either cisapride or mosapride, and itopride should also be considered a welcome treatment addition for symptomatic nonulcer dyspepsia and other gastric motility disorders.
== History == Phage display was first described by George P. Smith in 1985, when he demonstrated the display of peptides on filamentous phage (long, thin viruses that infect bacteria) by fusing the virus's capsid protein to one peptide out of a collection of peptide sequences. This displayed the different peptides on the outer surfaces of the collection of viral clones, where the screening step of the process isolated the peptides with the highest binding affinity. In 1988, Stephen Parmley and George Smith described biopanning for affinity selection and demonstrated that recursive rounds of selection could enrich for clones present at 1 in a billion or less. In 1990, Jamie Scott and George Smith described creation of large random peptide libraries displayed on filamentous phage. Phage display technology was further developed and improved by groups at the Laboratory of Molecular Biology with Greg Winter and John McCafferty, The Scripps Research Institute with Richard Lerner and Carlos Barbas and the German Cancer Research Center with Frank Breitling and Stefan Dübel for display of proteins such as antibodies for therapeutic protein engineering. Smith and Winter were awarded a half share of the 2018 Nobel Prize in chemistry for their contribution to developing phage display. A patent by George Pieczenik claiming priority from 1985 also describes the generation of peptide libraries.
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.
No. Cardarine has not received approval for human therapeutic use in major jurisdictions. It remains an investigational compound.