If you have been reading about Anti-doping testing and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Last reviewed on 2026-05-05. Where a claim depends on a specific study, the study is described rather than over-claimed.
The compound is typically described as a laboratory compound rather than a therapeutic product. Published reports have explored its role in lipid disorders, insulin sensitivity, and exercise metabolism, yet no major drug regulator has approved it for medical use. Commercial samples sold under the cardarine name may vary in purity and identity. Analytical confirmation is therefore necessary when the material is discussed in scientific or regulatory contexts. Its classification as a prohibited substance in sport further shapes how it is studied and reported.
Cardarine is a common name for GW501516, a synthetic compound studied for its effects on lipid and glucose metabolism. It functions as an agonist at peroxisome proliferator-activated receptor delta, or PPARδ, a nuclear receptor that influences gene expression. The molecule is not a steroid, nor is it a selective androgen receptor modulator. It is also known in research and sports literature as GW-501516 and endurobol. Early laboratory work examined its metabolic activity in cell cultures and animal models.
Activation of PPARδ changes transcription of genes involved in fatty acid transport, mitochondrial function, and skeletal muscle fuel preference. In rodent studies, pharmacological PPARδ activation was associated with increased endurance and altered body composition. These findings generated interest in performance enhancement, but species differences and study designs limit direct extrapolation to humans. Small human trials were conducted in the 2000s and later discontinued. The extent to which cardarine produces similar metabolic or performance effects in people remains an open question.
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.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic PPARδ agonist | Not a steroid or a selective androgen receptor modulator. |
| Common synonyms | Cardarine, GW501516, GW-501516, endurobol | Names vary by supplier and literature source. |
| Appearance | White to off-white powder | Consistent with many small-molecule research chemicals. |
| Solubility | Low in water; soluble in DMSO and ethanol | Often prepared in organic solvent for laboratory work. |
| Primary target | PPARδ (NR1C2) | Nuclear receptor involved in lipid and energy metabolism. |
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.
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.
GW501516 acts on PPARδ, a nuclear receptor that helps regulate fatty acid oxidation and energy homeostasis. In animal studies, activation of this receptor was associated with increased endurance and changes in lipid metabolism. Human trials examined effects on blood lipids and other metabolic markers, but the compound did not advance to approval. Rodent studies later reported tumors in multiple tissues at doses used in those experiments. Whether those findings translate to human risk remains uncertain, and the clinical relevance of the animal data is still debated.
Regulatory bodies treat GW501516 as a prohibited substance in competitive sport. The World Anti-Doping Agency added it to the prohibited list, and it falls under classes covering metabolic modulators and hormone-related agents. It is not approved by drug regulators for human use, and it is not a lawful dietary supplement. Products sold under the cardarine name may contain unlisted ingredients or different compounds. Because no approved product exists, quality and identity are not guaranteed by pharmaceutical manufacturing standards.
Cardarine is a common name for the investigational chemical GW501516, also written GW-1516. It was developed as a peroxisome proliferator-activated receptor delta agonist for metabolic conditions such as dyslipidemia. Early research focused on lipid handling and energy use in skeletal muscle and other tissues. The compound was never approved as a medicine. In public discussion, it is often grouped with performance-enhancing substances, although its receptor target differs from that of anabolic steroids or selective androgen receptor modulators. Regulatory and health authorities have issued warnings about its use.
=== Abuse === Unlike other carbamates such as meprobamate and its prodrug carisoprodol, methocarbamol has greatly reduced abuse potential. Studies comparing it to the benzodiazepine lorazepam and the antihistamine diphenhydramine, along with placebo, find that methocarbamol produces increased "liking" responses and some sedative-like effects; however, at higher doses dysphoria is reported. It is considered to have an abuse profile similar to, but weaker than, lorazepam.
=== Pharmacodynamics === Tandospirone acts as a potent and selective 5-HT1A receptor partial agonist, with a Ki affinity value of 27 ± 5 nM and approximately 55 to 85% intrinsic activity. It has relatively weak affinity for the 5-HT2A (1,300 ± 200), 5-HT2C (2,600 ± 60), α1-adrenergic (1,600 ± 80), α2-adrenergic (1,900 ± 400), D1 (41,000 ± 10,000), and D2 (1,700 ± 300) receptors, and is essentially inactive at the 5-HT1B, 5-HT1D, β-adrenergic, and muscarinic acetylcholine receptors, serotonin transporter, and benzodiazepine allosteric site of the GABAA receptor (all of which are > 100,000). There is evidence of tandospirone having low but significant antagonistic activity at the α2-adrenergic receptor through its active metabolite 1-(2-pyrimidinyl)piperazine (1-PP). Tandospirone has been found to produce antiaggressive effects in rodents. It has been found to increase oxytocin levels in rodents.
"What we know about the US-Israeli attack on Iran and Tehran's retaliation". CNN. 28 February 2026. Retrieved 28 February 2026. U.S. and Israeli Strikes on Iran, C-SPAN Tracking of traffic in the Strait of Hormuz
==== Cancer health claims ==== The U.S. Food and Drug Administration initiated a process of reviewing and approving food and dietary supplement health claims in 1993. Reviews of petitions results in proposed claims being rejected or approved. If approved, specific wording is allowed on package labels. In 1999, a second process for claims review was created. If there is not a scientific consensus on the totality of the evidence, a Qualified Health Claim (QHC) may be established. The FDA does not "approve" qualified health claim petitions. Instead, it issues a Letter of Enforcement Discretion that includes very specific claim language and the restrictions on using that wording. The first QHCs relevant to vitamin E were issued in 2003: "Some scientific evidence suggests that consumption of antioxidant vitamins may reduce the risk of certain forms of cancer." In 2009, the claims became more specific, allowing that vitamin E might reduce the risk of renal, bladder and colorectal cancers, but with required mention that the evidence was deemed weak and the claimed benefits highly unlikely. A petition to add brain, cervical, gastric and lung cancers was rejected. A further revision, May 2012, allowed that vitamin E may reduce risk of renal, bladder and colorectal cancers, with a more concise qualifier sentence added: "FDA has concluded that there is very little scientific evidence for this claim." Any company product label making the cancer claims has to include a qualifier sentence.
The American kestrel is likely the most abundant falcon in North America, although its total population is difficult to quantify, as local populations can change quickly due to resource availability. Count data from the USGS Breeding Bird Survey (BBS) indicate that the North American breeding population is experiencing long-term and gradual but sustained declines, with some regions, such as New England and coastal California, exhibiting more rapid declines. Count data from raptor migration corridors also indicate regional population declines and largely corroborate BBS data. The North American population has been estimated at 1.2 million pairs, with the Central and South American populations being as large. A smaller estimate is 236,000 birds wintering in North America. A population increase occurred in the 18th and 19th centuries, probably due to deforestation for agriculture. The resulting pastures provided an ideal habitat for kestrels. As of its 2025 IUCN assessment, the global population of American kestrels is estimated to be 9.2 million mature individuals. The southeastern U.S. subspecies (Falco sparverius paulus) has declined 82% since 1940 due to a decrease in nest site availability. This decline is a result of longleaf pines being cleared for agricultural fields. Despite this, the American kestrel is classed as least concern on the IUCN Red List. The Peregrine Fund, a leading non-profit organization advancing research and conservation of birds of prey worldwide, launched the American Kestrel Partnership in 2012.
Sources: en.wikipedia.org
=== Acquisition by Take-Two Interactive (2024–present) === Take-Two Interactive announced its plans to acquire Gearbox Entertainment and its intellectual properties from Embracer Group for $460 million on March 28, 2024, to be added under the 2K label. The acquisition also includes Gearbox Software with its satellite studios and Gearbox Publishing. Embracer will retain Gearbox San Francisco, Gearbox Shanghai, Lost Boys Interactive, Captured Dimensions, and Cryptic Studios, along with publishing rights to Remnant, Hyper Light Breaker, and other unannounced titles. Less than a day after the announcement, it was reported that an unknown number of employees were laid off from Gearbox. On June 12, 2024, Take-Two Interactive closed the Gearbox Software transaction.
The proliferation of such technology could also make the production of biological and chemical weapons available to a wider array of state and non-state actors. These security issues may be avoided by regulating industry uses of biotechnology through policy legislation. Federal guidelines on genetic manipulation are being proposed by "the President's Bioethics Commission ... in response to the announced creation of a self-replicating cell from a chemically synthesized genome, put forward 18 recommendations not only for regulating the science ... for educating the public".
Gilbert Frankau writer Pamela Frankau (3 January 1908 – 8 June 1967) popular novelist from a prominent artistic and literary family who wrote over thirty novels; grandmother was novelist Julia Frankau; father was Gilbert Frankau; partner was Italian-Jewish poet Humbert Wolfe. Sally Herbert Frankel (1903–1996) author of over five influential texts on economics and colonial settlement in South Africa; Professor of Colonial Economic Affairs and Economics of Underdeveloped Countries at Oxford University in period following Second World War; originally from South Africa, of German-Jewish descent, he moved to England after the Second World War. He joined the Mont Pelerin Society in 1950. Frankel was committed to principle of Jewish peoplehood and was keen Zionist. Ronald Frankenberg (1929–2015); anthropologist and sociologist, known for his study of conflict and decision-making and development of medical anthropology; was member of Manchester School of British Social Anthropology; was married to Dr. Pauline Frankenberg (née Hunt), author of Gender and Class Consciousness (1980). One of his daughters was sociologist Ruth Frankenberg. Ruth Frankenberg (1957–2007); social scientist and feminist, known for her pioneering work in field of whiteness studies; author of White Women, Race Matters: The Social Construction of Whiteness; prolific contributor to many journals on the study of whiteness, including her essay The Mirage of an Unmarked Whiteness.
== Causes == Hair insertion is the causative agent of pilonidal cysts. An analysis of 624 patients' cyst hair found that 74% of the hair was rootless, and resembled spiky, razor-cut hair rather than intact body hair. One proposed cause is ingrown hair, although hairs found in pilonidal sinus tracts have more often been found to originate from the head. Excessive sitting is thought to predispose people to the condition, as sitting increases pressure on the coccygeal region. Trauma is not believed to cause a pilonidal cyst; however, such an event may result in inflammation of an existing cyst. There are cases where this has occurred months after a localized injury to the area. Pilonidal cysts may be caused by a congenital pilonidal dimple. Excessive sweating can also contribute to the formation of a pilonidal cyst: moisture can fill a stretched hair follicle, which helps create a low-oxygen environment that promotes the growth of anaerobic bacteria, often found in pilonidal cysts. The presence of bacteria and low oxygen levels hamper wound healing and exacerbate a developing pilonidal cyst.
The Welsh Romance Peredur son of Efrawg is based on Chrétien or derived from a common original, but it contains several prominent deviations and lacks a Grail. The character of the Fisher King appears (though he is not called such) and presents Peredur with a severed head on a platter. Peredur later learns that he was related to that king, and that the severed head was that of his cousin, whose death he must avenge by defeating the Nine Witches.
Sources: en.wikipedia.org
Cardarine is a common name for GW501516, a synthetic PPARδ agonist. It is not a steroid or a selective androgen receptor modulator. It was developed and studied as a research compound for metabolic pathways.
It binds to and activates PPARδ, a nuclear receptor that regulates genes related to fatty acid oxidation and energy use. This activation alters transcription in tissues such as skeletal muscle and liver. The full range of downstream effects in humans is not fully established.
No, cardarine is not known to occur naturally in plants, animals, or humans. It is a synthetic molecule produced for laboratory research. Products labeled as cardarine should therefore be treated as manufactured chemicals with variable purity.
No. Major drug regulators have not approved GW501516 for treating any medical condition. Products sold as cardarine are typically unapproved research chemicals or supplements, so their contents and safety are not assured.