anti-doping is one of those subjects where the details matter more than the headlines. This page pulls together the background, the mechanisms, and the practical points readers ask about most.
Updated 2026-04-16. Numbers and descriptions here follow the published literature rather than marketing material.
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.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Common name | Cardarine | Common internet and media name. |
| Research code | GW501516 | Also written GW-1516. |
| Drug class | PPARδ agonist | Not a selective androgen receptor modulator. |
| Development status | Discontinued | Clinical development halted after rodent cancer findings. |
| Regulatory status | Prohibited in sport | Listed by WADA; not approved as medicine. |
Anti-doping laboratories identify GW501516 and its metabolites using liquid chromatography-tandem mass spectrometry. Urine is the usual matrix, and detection can occur after the parent compound has cleared from blood. The exact detection window depends on dose, formulation, individual metabolism, and assay sensitivity. Because the compound is prohibited at all times, athletes are subject to testing in and out of competition. Analytical methods continue to improve as new metabolites and designer analogs are characterized.
GW501516 acts as a ligand for PPAR delta, a nuclear receptor that regulates transcription of genes involved in fatty acid oxidation and energy use. Activation of this receptor in skeletal muscle shifts metabolism toward fat burning in animal models. The compound does not burn fat directly; it changes gene expression over hours to days. Researchers study it to understand metabolic flexibility and exercise adaptation. Effects observed in rodents are not automatically expected in humans.
Preclinical research reported that GW501516 increased running endurance in mice and improved lipid profiles in some animal species. Early human trials explored effects on high-density lipoprotein cholesterol, triglycerides, and glucose handling, but the program was discontinued. Published human data are sparse and do not establish efficacy for any condition. Studies also examined PPAR delta in cancer biology, with conflicting findings across models. The relationship between receptor activation, tissue context, and disease risk remains an active area of investigation.
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.
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.
== Names == Dapagliflozin is the international nonproprietary name (INN), and the United States Adopted Name (USAN). The fixed-dose combination product, dapagliflozin/metformin extended-release, is sold under the brand name Xigduo XR. In July 2016, the fixed-dose combination of saxagliptin and dapagliflozin was authorized for medical use in the European Union and is sold under the brand name Qtern. The combination drug was approved for medical use in the United States in February 2017, where it also is sold under the brand name Qtern. In May 2019, the fixed-dose combination of dapagliflozin, saxagliptin, and metformin hydrochloride as extended-release tablets was approved in the United States to improve glycemic control in adults with type 2 diabetes when used in combination with diet and exercise. The FDA granted the approval of Qternmet XR to AstraZeneca. The combination drug was authorized for use in the European Union in November 2019, and is sold under the brand name Qtrilmet.
Smoking cessation may decrease the metabolism of acetaminophen, beta-blockers, caffeine, oxazepam, pentazocine, propoxyphene, theophylline, and tricyclic antidepressants, leading to higher plasma concentrations of these drugs. Possible alteration of nicotine absorption through the skin from the transdermal nicotine patch by drugs that cause vasodilation or vasoconstriction. Possible alteration of nicotine absorption through the nasal cavity from the nicotine nasal spray by nasal vasoconstrictors (e.g., xylometazoline). Possible alteration of nicotine absorption through oral mucosa from nicotine gum and lozenges by food and drink that modify salivary pH.
Lignans and lignin differ in their molecular weight, the former being small and soluble in water, the latter being high polymers that are undigestable. Both are polyphenolic substances derived by oxidative coupling of monolignols. Thus, most lignans feature a C18 cores, resulting from the dimerization of C9 precursors. The coupling of the lignols occurs at C8. Eight classes of lignans are: "furofuran, furan, dibenzylbutane, dibenzylbutyrolactone, aryltetralin, arylnaphthalene, dibenzocyclooctadiene, and dibenzylbutyrolactol." Many lignans are metabolized by mammalian gut microflora, producing so-called enterolignans.
Terrestrial data backs this idea by showing multiple periods of ejecta in the rock record both before and after the 3.9 Gya marker, suggesting that the early Earth was subject to continuous impacts with less impact on extinction. If life evolved in the ocean at depths of more than ten meters, it would have been shielded both from late impacts and the then high levels of ultraviolet radiation from the sun. The available energy is maximized at 100–150 °C, the temperatures at which hyperthermophilic bacteria and thermoacidophilic archaea live.
Sources: en.wikipedia.org
== Usefulness of NTX as a biomarker == Evaluating an individual's rate of bone turnover, termed bone remodeling, directly may be important in assessing his or her potential nonsurgical treatment response as well as evaluating his or her risk of developing complications during healing following surgical intervention. To determine an individual's rate of bone turnover, numerous biomarkers are available in the body fluids that can be correlated to this rate, and one such biomarker is NTX. However, while NTX does fluctuate in a very sensitive manner in line with bone resorption patterns, they are not very specific, in that they may vary spontaneously without physiologic intervention. For example, NTX levels may drop by 50% from day to day with no treatment, thus, making NTX levels unconvincing evidence of treatment effect. Conversely, the serum CTX biomarker, described in 2000 by Rosen, appears to be a much more effective and valuable indicator of bone resorption rate.
Black Widow Games was a video game developer specializing in promotional mods for Quake and Half-Life 3D engines. They are best known for their They Hunger series. Prominent members included Neil Manke (game and level design), Einar Saukas (game design and coding), and Magnus Jansén (game consultant and sound engineer). The company business model is based on developing contract-work mods for the marketing campaigns of customer companies and products (such as the S.O.F. TV series from Rysher Entertainment and the movie Underworld from Sony Pictures), freely distributed for promotion.
=== Novel technologies === Tecemotide is based on novel technologies, which may raise new regulatory issues that could delay or complicate regulatory approval. Additionally, as of 2013, the FDA had approved for commercial sale in the United States only one active vaccine designed to stimulate an immune response against cancer. Consequently, there is limited precedent for the successful development or commercialization of products based on these technologies in this area.
A pi helix (or π-helix) is a type of secondary structure found in proteins. Discovered by crystallographer Barbara Low in 1952 and once thought to be rare, short π-helices are found in 15% of known protein structures and are believed to be an evolutionary adaptation derived by the insertion of a single amino acid into an α-helix. Because such insertions are highly destabilizing, the formation of π-helices would tend to be selected against unless it provided some functional advantage to the protein. π-helices therefore are typically found near functional sites of proteins.
=== Location === Metalloids lie on either side of the dividing line between metals and nonmetals. This can be found, in varying configurations, on some periodic tables. Elements to the lower left of the line generally display increasing metallic behaviour; elements to the upper right display increasing nonmetallic behaviour. When presented as a regular stairstep, elements with the highest critical temperature for their groups (Li, Be, Al, Ge, Sb, Po) lie just below the line.
Sources: en.wikipedia.org
The messages revealed that his friendship with Epstein lasted for nine years, including well after Epstein was initially charged with soliciting sex from a minor. Ariely also suggested that Epstein use learnings from his research to help rehabilitate his public image, stating via email, "If you want to talk about where to take this research or other questions...[l]et me know." Ariely said in response: "At the time of our meetings, I was deep into research on dishonesty and crime, and I spoke with many individuals who had broken the law..." and "our relationship wasn't a friendship, and he didn't financially support any of my projects."
== Rationale == Long-term studies like the UK Prospective Diabetes Study (UKPDS) and the Diabetes control and complications trial (DCCT) showed that intensive insulin therapy achieved blood glucose levels closer to non-diabetic people and that this was associated with reduced frequency and severity of blood vessel damage. Damage to large and small blood vessels (macro- and microvascular disease) is central to the development of complications of diabetes. This evidence convinced most physicians who specialize in diabetes care that an important goal of treatment is to make the biochemical profile of the diabetic patient (blood lipids, HbA1c, etc.) as close to the values of non-diabetic people as possible. This is especially true for young patients with many decades of life ahead.
== Birth and education == Bernard Horecker was born in Chicago on 31 October 1914. He studied at the University of Chicago and obtained his Ph.D. there in 1939. Laureate honoris causa in Biological Sciences, University of Urbino, Italy, 1982.
== Use and effects == EiPLA has been identified in blotter containing doses of 86 to 97 μg base equivalent per tab. Blotter containing 200 μg per tab has also been described. Anecdotal reports suggest that EiPLA produces psychedelic effects but is less potent than LSD.
== Spectrum == The mass spectrum of the secondary ions emitted from the bombarded surface during SSIMS provides direct information of not only the chemical composition but also of the chemical structure of the bombarded area. This is because the mass spectrum includes cluster ions as well as elemental ions. These cluster ions reflect the surface chemistry in a detailed way. The figure shows the mass spectrum obtained from a SSIMS analysis of polytetrafluoroethylene (PTFE). The positive ion spectrum shows positive atomic ions (i.e. C+) and molecular ions (i.e. CF+, CF3+, C3F3+) of the target. The negative ion spectrum shows negative atomic ions (i.e. F−) and molecular ions (i.e. F2−, CF3−, C3F3−).
Sources: en.wikipedia.org
No. Cardarine is a PPARδ agonist, while selective androgen receptor modulators act on androgen receptors. The two classes differ in receptor target and downstream effects.
Preclinical rodent studies reported cancers, including liver and bladder tumors, at tested doses. The human relevance of those findings is uncertain, but development was discontinued. No approved human product resulted.
No. It remains an investigational compound without approved therapeutic labeling. Sports regulators prohibit its use, and health agencies have warned against consuming it.
Anti-doping laboratories typically use LC-MS/MS to detect GW501516 and its metabolites in urine. The method is sensitive and can identify the compound at low concentrations. Detection depends on sample timing, metabolism, and the specific assay.