This is a working overview of LC-MS/MS, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2026-07-27 and is reviewed periodically as new material appears.
Sporting authorities added GW501516 to prohibited lists after it appeared in athlete samples and online markets. The World Anti-Doping Agency classifies it as a hormone and metabolic modulator, and its use can lead to an anti-doping rule violation. Some early laboratory work suggested effects on fatty acid oxidation and endurance-related metabolism in animals, but those findings do not establish safe or effective use in people. Reports of adverse events in humans are scarce and often anecdotal, which complicates risk assessment.
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 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.
| Property | Value | Notes |
|---|---|---|
| IUPAC name | {4-[({4-methyl-2-[4-(trifluoromethyl)phenyl]-1,3-thiazol-5-yl}methyl)sulfanyl]phenoxy}acetic acid | Systematic name for GW501516 |
| CAS Registry Number | 317318-70-0 | Unique identifier for the parent compound |
| Molecular formula | C21H18F3NO3S2 | Includes carbon, hydrogen, fluorine, nitrogen, oxygen, and sulfur |
| Molecular weight | 453.5 g/mol | Approximate value for the neutral form |
| Appearance | White to off-white powder | Typical description for purified laboratory material |
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.
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.
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.
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.
== External links == "Chain of Being" in the Dictionary of the History of Ideas The Great Chain of Being reflected in the work of Descartes, Spinoza & Leibniz. Archived 2008-08-28 at the Wayback Machine. Peter Suber, Earlham College, Indiana
On July 22, 2025, the United States informed of its decision to withdraw from UNESCO, effective December 31, 2026. In a presidential memorandum issued on January 7, 2026, Donald Trump directed to start the process of withdrawal of the US from the 66 organizations, agencies and commissions of the United Nations, including UN Framework Convention on Climate Change (UNFCCC), calling them "contrary to the interests of the United States".
=== Miscellaneous === Italian police sought bribery charges in May 2004, against 4,400 doctors and 273 GSK employees. GSK and its predecessor were accused of having spent £152m on physicians, pharmacists and others, giving them cameras, computers, holidays and cash. Doctors were alleged to have received cash based on the number of patients they treated with a cancer drug, topotecan (Hycamtin). The following month prosecutors in Munich accused 70–100 doctors of having accepted bribes from SmithKline Beecham between 1997 and 1999. The inquiry was opened over allegations that the company had given over 4,000 hospital doctors money and free trips. All charges were dismissed by the Verona court in January 2009. In 2006, in the United States GSK settled the largest tax dispute in IRS history, agreeing to pay US$3.1 billion. At issue were Zantac and other products sold in 1989 to 2005. The case revolved around intracompany transfer pricing—determining the share of profit attributable to the US subsidiaries of GSK and subject to tax by the IRS. The UK's Serious Fraud Office (SFO) opened a criminal inquiry in 2014 into GSK's sales practices, using powers granted by the Bribery Act 2010. The SFO said it was collaborating with Chinese authorities to investigate bringing charges in the UK related to GSK's activities in China, Europe and the Middle East. Also as of 2014, the US Department of Justice was investigating GSK with reference to the Foreign Corrupt Practices Act.
=== Advantages === One of the advantages to automation is faster processing, but it is not necessarily faster than a human operator. Repeatability and reproducibility are improved as automated systems as less likely to have variances in reagent quantities and less likely to have variances in reaction conditions. Typically productivity is increased since human constraints, such as time constraints, are no longer a factor. Efficiency is generally improved as robots can work continuously and reduce the amount of reagents used to perform a reaction. Also there is a reduction in material waste. Automation can also establish safer working environments since hazardous compounds do not have to be handled. Additionally automation allows staff to focus on other tasks that are not repetitive.
=== Pharmacokinetics === A lipophilic chemical that can easily cross the blood–brain barrier, carfentanil has a very rapid onset of action and is longer acting than fentanyl. Its elimination half-life in humans was 42 to 51 minutes following an intravenous bolus at an average dose of 1.34 μg (19 ng/kg). However, in a case study of recreational exposure, the half-lives of carfentanil and its metabolite norcarfentanil were estimated to be 5.7 hours and 11.8 hours, respectively.
Sources: en.wikipedia.org
== History == Two main studies showed that treosulfan is at least as effective as busulfan, another medicine used to prepare people for haematopoietic stem cell transplantation. In one of the studies, involving 570 adults with acute myeloid leukaemia (a blood cancer) or myelodysplastic syndromes (conditions in which large numbers of abnormal blood cells are produced), 64% of patients given treosulfan (with fludarabine) had a successful transplant and were alive and disease-free after 2 years, compared with 51% of patients given busulfan (with fludarabine). In an additional study in 70 children with blood cancers, 99% of children given treosulfan (with fludarabine) were alive three months after their transplant. Efficacy was evaluated in MC-FludT.14/L Trial II (NCT00822393), a randomized active-controlled trial comparing treosulfan to busulfan with fludarabine as a preparative regimen for allogeneic transplantation. Eligible patients included adults 18 to 70 years old with AML or MDS, Karnofsky performance status ≥ 60%, and age ≥ 50 years or hematopoietic cell transplantation comorbidity index [HCTCI] score > 2. There were 570 patients randomized to treosulfan (n=280) or busulfan (n=290).
==== Inhibition of DNA repair ==== Inhibition of DNA repair processes is considered one of main mechanism of inorganic arsenic genotoxicity. Nucleotide excision repair (NER) and base excision repair (BER) are the processes implicated in the repair of DNA base damage induced by ROS after arsenic exposure. In particular, the NER mechanism is the major pathway for repairing bulky distortions in DNA double helix, while the BER mechanism is mainly implicated in the repair of single strand breaks induced by ROS, but inorganic arsenic could also repress the BER mechanism. Exposure of isolated lymphocytes to arsenic causes decreased expression of the DNA repair protein ERCC1. Consistent with an inhibitory effect on DNA repair, lymphocytes from arsenic exposed individuals have higher levels of DNA damage. Arsenic can act as a co-carcinogen by inhibiting repair of DNA damage through its interaction with sensitive zinc finger DNA repair proteins.
== Campaigning and activism == Child sponsorship charity ActionAid has published an article discussing corrective rape, and see ending violence against women as a pivotal part of their mission. The group joined with 26 gay and women's rights and community groups, to organize a campaign focused on South Africa but also aimed at the international community, to raise awareness of the issues. The campaign was dedicated to raising awareness about the rape and murder of two lesbian women in a Johannesburg township and called for sexual orientation to be specifically recognised as grounds for protection by police and justice systems. Ndumie Funda, a South African Social Justice Activist, started her work to end corrective rape by launching a social campaign on Change.org in hopes to have the South African Government recognize hate crimes committed due to biases against sexual orientation and provide protection for victims. This particular petition ended up gathering almost 200 thousand signatures from individuals making up over 175 countries, forcing the government to recognize this issue. The government agreed to meet Funda and in 2014 South Africa passed its first law against hate crimes.
proteinogenic amino acid Any of the 20 canonical amino acids which are encoded by the standard genetic code and incorporated into peptides and ultimately proteins during translation. The term may also be inclusive of an additional two amino acids encoded by non-standard codes which can be incorporated by special translation mechanisms.
Sources: en.wikipedia.org
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.
It is prohibited by the World Anti-Doping Agency as a hormone and metabolic modulator. Athletes who test positive for GW501516 can face sanctions, including suspensions and loss of results.
Cardarine is a common or trade-style name, while GW501516 is the research code for the same chemical entity. Some sources also use Endurobol or GSK-516. The names refer to the same compound, not distinct drugs.
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.