GW501516 raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
Reviewed 2025-12-29. Anything still debated is marked as such rather than presented as settled.
Safety discussions about cardarine frequently cite rodent carcinogenicity findings reported in the 2000s. In those studies, treated animals developed tumors at multiple sites, leading sponsors to discontinue clinical development. The relevance of these findings to humans has not been resolved, but they are a major reason the compound is not approved. Current literature emphasizes uncertainty about long-term effects and the risks of unregulated use. Regulators and health agencies have not established a safe human exposure level.
Cardarine is a synthetic compound also known as GW501516, GW-501516, and sometimes endurobol. It was developed as a selective agonist of peroxisome proliferator-activated receptor delta, a nuclear receptor involved in fatty acid oxidation and energy metabolism. The compound was studied in preclinical models for metabolic and cardiovascular conditions, but it did not become a marketed human medicine. In regulatory and anti-doping contexts, it is treated as a prohibited substance rather than a licensed medicine.
The pharmacological interest in cardarine centers on PPARδ activation and its downstream effects on lipid handling and mitochondrial function. In animal studies, PPARδ agonists have been associated with changes in exercise endurance and fatty acid utilization, though results vary by model and protocol. Human data remain sparse, and the absence of large controlled trials limits conclusions about efficacy. Researchers often describe the compound as a tool for probing PPARδ biology rather than a proven therapeutic agent.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Common synonyms | GW501516, GW-501516, GW 501516, endurobol | Names vary in research and anti-doping documents. |
| Chemical class | Synthetic PPARδ agonist | Small-molecule nuclear receptor ligand. |
| CAS Registry Number | 317318-70-0 | Identifier commonly associated with GW501516. |
| Appearance | White to off-white powder | Typical for purified research material. |
| Solubility | Low in water; soluble in DMSO and ethanol | Organic solvents are common for laboratory stock solutions. |
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.
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.
== External links == MedlinePlus Encyclopedia: Gamma-glutamyl transpeptidase (GGT) blood test gamma-Glutamyltransferase at the U.S. National Library of Medicine Medical Subject Headings (MeSH) GGT - Lab Tests Online Overview of all the structural information available in the PDB for UniProt: P19440 (Gamma-glutamyltransferase 1) at the PDBe-KB.
== Efficiency of bond-skipping == Different 2A peptides have different peptide-bond-skipping efficiencies, with T2A and P2A being the most efficient and F2A the least efficient. Therefore, up to 50% of F2A-linked proteins can in fact be produced as a fusion protein, which might cause some unpredictable outcomes, including a gain of function. One study reported that 2A sites cause the ribosome to fall off approximately 60% of the time, and that, together with ribosome read-through of about 10% for P2A and T2A, this results in reducing expression of the downstream peptide chain by about 70%. However, the level of drop-off detected in this study varied widely depending on the exact construct used, with some constructs showing little evidence of drop-off; furthermore, within a tri-cistronic transcript it reported a higher level of ribosome drop-off after one 2A sequence than after two 2As combined, which is at odds with a linear model of translation.
=== Serving chicken without antibiotics === In February 2014, Chick-fil-A announced plans to serve chicken raised without antibiotics in its restaurants nationwide within five years, the first fast-food restaurant to make this commitment. This was implemented by May 2019. Later the company stated that "to maintain supply of the high-quality chicken", they would shift from a policy of No Antibiotics Ever (NAE) to No Antibiotics Important To Human Medicine (NAIHM) starting in the spring of 2024. In March 2024, Chick-fil-A announced it would depart from the company's previous commitment of using only "antibiotic-free" chicken.
=== About Dyson === "Freeman Dyson's Brain", interview by Stewart Brand at Wired, 1998 2008 Video Interview with Freeman Dyson by Atomic Heritage Foundation, Voices of the Manhattan Project Roberts, Russ (7 March 2011). "Dyson on Heresy, Climate Change, and Science". EconTalk. Library of Economics and Liberty. "Freeman Dyson: 'I kept quiet for thirty years, maybe it's time to speak'". 52 Insights. 15 June 2018. Retrieved 25 November 2019. Remembering the Unstoppable Freeman Dyson Freeman Dyson at TED Freeman J. Dyson, a Biographical Memoir by Ann Finkbeiner and William H. Press.
Sources: en.wikipedia.org
== Function == The protein encoded by this gene is the predominant constituent of the crystalline core of the eosinophil granule. High levels of the proform of this protein are also present in placenta and pregnancy serum, where it exists as a complex with several other proteins including pregnancy-associated plasma protein A (PAPPA), angiotensinogen (AGT), and C3dg. This protein may be involved in antiparasitic defense mechanisms as a cytotoxin and helmintho-toxin, and in immune hypersensitivity reactions. It is directly implicated in epithelial cell damage, exfoliation, and bronchospasm in allergic diseases. PRG2 is a 117-residue protein that predominates in eosinophil granules. It is a potent enzyme against helminths and is toxic towards bacteria and mammalian cells in vitro. The eosinophil major basic protein also causes the release of histamine from mast cells and basophils, and activates neutrophils and alveolar macrophages.
== Environmental issues == Light pollution: Because white LEDs emit more short wavelength light than sources such as high-pressure sodium vapor lamps, the increased blue and green sensitivity of scotopic vision means that white LEDs used in outdoor lighting cause substantially more sky glow. Impact on wildlife: LEDs are much more attractive to insects than sodium-vapor lights, so much so that there has been speculative concern about the possibility of disruption to food webs. LED lighting near beaches, particularly intense blue and white colors, can disorient turtle hatchlings and make them wander inland instead. The use of "turtle-safe lighting" LEDs that emit only at narrow portions of the visible spectrum is encouraged by conservancy groups in order to reduce harm. Use in winter conditions: Since they do not give off much heat in comparison to incandescent lights, LED lights used for traffic control can have snow obscuring them, leading to accidents.
For services to Animal Health and voluntary service to Sport. Madeleine Clare Hinch, MBE. For services to Hockey. Elaine Hinchliffe-Dale (Elaine Dale). Director, Special Educational Needs and Disabilities Support, City College Norwich. For services to Further Education. Dr. Elizabeth Janine Hogben. Lately Secretary, Prime Minister's Council for Science and Technology, Government Office for Science. For services to Science in Government. Lady (Patricia Ann) Hopkins. For services to Architecture. Carol Wai Wing Hui. Lately Board Member, British Tourist Authority. For services to Tourism. Mahboob Hussain, JP. For services to the community in Buckinghamshire. Elizabeth Louise Hutton. Chief Executive Officer, Kicks Count. For services to Education and Prevention of Stillbirths. Alasdair Bruce Jackson. Chief Executive, Recycling Lives Charity. For services to the Rehabilitation of Offenders. Kerry Joanne Jackson. Chief Executive, St Gemma's Hospice. For services to Palliative and End of Life Care. Salim Hassanali Moledina Janmohamed. For charitable and voluntary services to Faith Communities. Peter Jefferies. Team Leader, Ministry of Defence. For services to Defence. Timothy Nigel Jenkins. Lately District Judge, Brentford County Court. For services to the Administration of Justice. Peter Sinclair Jensen. Lately Chair of Trustees, Home of Horseracing Trust and Chair, British Sporting Arts Trust. For Charitable Service. Dr. Christopher Paul Johnson. Forensic Pathologist, Home Office. For services to Criminal Justice. Christopher Jolly. Publisher, Jolly Phonics.
== Litigation == CLIA itself has not been the subject of much litigation. Federal district courts have held that the CLIA did not create a private cause of action for individuals to sue laboratories that do not comply with its provisions.
=== Use in executions === In 2009, Ohio approved the use of an intramuscular injection of 500 mg of hydromorphone and a supratherapeutic dose of midazolam as a backup means of carrying out executions by lethal injection when a suitable vein cannot be found for intravenous injection.
Sources: en.wikipedia.org
Susineridine (INNTooltip International Nonproprietary Name; developmental code name YZJ-4729) is an atypical μ-opioid receptor (MOR) agonist and opioid analgesic which is under development for the treatment of postoperative pain. It is given intravenously. The drug acts as a selective biased partial agonist of the MOR, with functional selectivity for activation of G protein signaling over β-arrestin2 recruitment. Its mechanism of action and pharmacological activity are said to be similar to those of oliceridine. However, in-vitro findings suggest that susineridine may have a greater degree of G protein bias than oliceridine. The drug produces analgesic effects in multiple animal models of pain and produces less respiratory depression than morphine or oliceridine. The pharmacokinetics of susineridine in humans have been studied. Susineridine was patented and first described in the scientific literature in 2023. It is under development by Shanghai Haiyan Pharmaceutical Technology in China. As of May 2025, the drug is in phase 3 clinical trials for postoperative pain.
Hetero Drugs is an Indian pharmaceutical company headquartered in Hyderabad and the world's largest producer of anti-retroviral drugs. Hetero's business includes APIs, generics, biosimilars, custom pharmaceutical services, and branded generics.
Lead poisoning (Pb), in contrast to arsenic poisoning, is caused by industrial materials, such as leaded gasoline and lead leached from plumbing. Use of leaded gasoline has declined precipitously since the 1970s. Lead (from lead(II) azide or lead styphnate used in firearms) gradually accumulates at firearms training grounds, contaminating the local environment and exposing range employees to a risk of lead poisoning. Beryllium poisoning (Be) is attributed to the ability of Be2+ to replace Mg2+ in some enzymes. Be has been classified by one agency as a carcinogen. Cadmium poisoning (Cd) came into focus with the discovery of itai-itai disease due to cadmium-contaminated waters resulting from mining in the Toyama Prefecture starting around 1912. The term refers to the severe pains (Japanese: 痛い, romanized: itai) people with the condition felt in the spine and joints. Cd2+ is thought to accumulate in the kidneys, where it tightly binds to the sulfur in cysteine-containing proteins. Cadmium is also present as a material used in many electronic devices, thus it can leach into groundwater after being disposed of into landfills of electronic waste. Chromium poisoning (Cr) is primarily due to hexavalent chromium, Cr+6, creating as a side effect of industrial processes. While hexavalent chromium is a known human carcinogen, and it has become widespread in the environment, the impact of environmental contamination with this element are not known. Mercury poisoning (Hg) came into sharp focus with the discovery of Minamata disease, named for the Japanese city of Minamata.
==== Non-genomic mechanisms ==== Testosterone signals not only through the nuclear AR, but also through mARs, including ZIP9 and GPRC6A. It has been proposed that differential signaling through mARs may be involved in the dissociation of the anabolic and androgenic effects of AAS. Indeed, DHT has less than 1% of the affinity of testosterone for ZIP9, and the synthetic AAS metribolone and mibolerone are ineffective competitors for the receptor similarly. This indicates that AAS do show differential interactions with the AR and mARs. However, women with complete androgen insensitivity syndrome (CAIS), who have a 46,XY ("male") genotype and testes but a defect in the AR such that it is non-functional, are a challenge to this notion. They are completely insensitive to the AR-mediated effects of androgens like testosterone, and show a perfectly female phenotype despite having testosterone levels in the high end of the normal male range. These women have little or no sebum production, incidence of acne, or body hair growth (including in the pubic and axillary areas). Moreover, CAIS women have lean body mass that is normal for females but is of course greatly reduced relative to males. These observations suggest that the AR is mainly or exclusively responsible for masculinization and myotrophy caused by androgens. The mARs have however been found to be involved in some of the health-related effects of testosterone, like modulation of prostate cancer risk and progression.
== Detection == Protein array detection methods must give a high signal and a low background. The most common and widely used method for detection is fluorescence labeling which is highly sensitive, safe and compatible with readily available microarray laser scanners. Other labels can be used, such as affinity, photochemical or radioisotope tags. These labels are attached to the probe itself and can interfere with the probe-target protein reaction. Therefore, a number of label free detection methods are available, such as surface plasmon resonance (SPR), carbon nanotubes, carbon nanowire sensors (where detection occurs via changes in conductance) and microelectromechanical system (MEMS) cantilevers. All these label free detection methods are relatively new and are not yet suitable for high-throughput protein interaction detection; however, they do offer much promise for the future. Immunoassays on thiol-ene "synthetic paper" micropillar scaffolds have shown to generate a superior fluorescence signal. Protein quantitation on nitrocellulose coated glass slides can use near-IR fluorescent detection. This limits interferences due to auto-fluorescence of the nitrocellulose at the UV wavelengths used for standard fluorescent detection probes.
Sources: en.wikipedia.org
Cardarine is an investigational synthetic compound that acts as a PPARδ agonist. It is also known as GW501516 and has been studied mainly in preclinical research. It is not an approved medicine.
No. Cardarine is not a steroid hormone; it targets the nuclear receptor PPARδ. Its classification in anti-doping rules differs from anabolic steroids, though it remains prohibited in sport.
Early rodent studies reported tumor formation at multiple sites, which raised safety concerns. Sponsors stopped clinical development, and no approved human product exists.
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.