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Background And Regulatory Status — Background and Details

By Editorial Desk · published 2026-04-20 · last reviewed 2026-05-07 · News

Everything below concerns LC-MS/MS. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.

Last reviewed on 2026-05-07. Where a claim depends on a specific study, the study is described rather than over-claimed.

Background and Regulatory Status

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.

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.

Mechanism and Safety Research

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.

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.

Cardarine at a glance

PropertyValueNotes
IUPAC name{4-[({4-methyl-2-[4-(trifluoromethyl)phenyl]-1,3-thiazol-5-yl}methyl)sulfanyl]phenoxy}acetic acidSystematic name for GW501516
CAS Registry Number317318-70-0Unique identifier for the parent compound
Molecular formulaC21H18F3NO3S2Includes carbon, hydrogen, fluorine, nitrogen, oxygen, and sulfur
Molecular weight453.5 g/molApproximate value for the neutral form
AppearanceWhite to off-white powderTypical description for purified laboratory material

Regulation and Detection

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.

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Identity and Regulatory Status

Regulatory treatment varies, but cardarine is not approved as a medicine. Sports authorities list GW501516 as a prohibited substance, and it is banned at all times under the World Anti-Doping Agency code. Many countries restrict sales for human consumption, while online vendors market it as a research chemical. Such products may lack purity data, and their actual contents can differ from the label. Purchasing or possessing cardarine may carry legal consequences depending on jurisdiction. The compound is not a dietary supplement ingredient in regulated markets.

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.

Mechanism and Detection

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.

Identity and Pharmacological Mechanism

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.

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.

Further detail

=== Brand names === Naltrexone is or has been sold under a variety of brand names, including Adepend, Antaxone, Celupan, Depade, Destoxican, Nalorex, Narcoral, Nemexin, Nodict, Revia, Trexan, Vivitrex, and Vivitrol. It is also marketed in combination with bupropion (naltrexone/bupropion) as Contrave, and was marketed with morphine (morphine/naltrexone) as Embeda. A combination of naltrexone with buprenorphine (buprenorphine/naltrexone) has been developed, but has not been marketed.

As part of Biden's Build Back Better agenda, in late March 2021, he proposed the American Jobs Plan, a $2 trillion package addressing issues including transport infrastructure, utilities infrastructure, broadband infrastructure, housing, schools, manufacturing, research and workforce development. After months of negotiations among Biden and lawmakers, in August 2021 the Senate passed a $1 trillion bipartisan infrastructure bill called the Infrastructure Investment and Jobs Act, while the House, also in a bipartisan manner, approved that bill in early November 2021, covering infrastructure related to transport, utilities, and broadband. Biden signed the bill into law in mid-November 2021. The other core part of the Build Back Better agenda was the Build Back Better Act, a $3.5 trillion social spending bill that expands the social safety net and includes major provisions on climate change. Democrats attempted to pass it on a party-line vote through budget reconciliation, but struggled to win the support of Senator Joe Manchin, even as the price was lowered to $2.2 trillion. After Manchin rejected the bill, it was comprehensively reworked into the Inflation Reduction Act of 2022, covering deficit reduction, climate change, healthcare, and tax reform. The Inflation Reduction Act of 2022 was introduced by Manchin and Senator Chuck Schumer.

The Bermuda Triangle does not have any more shipwrecks or mysterious disappearances than most other waterways. Toilet waste is never intentionally jettisoned from commercial aircraft. All waste is collected in tanks and emptied into lavatory service vehicles. Blue ice is caused by accidental leakage from the waste tank. Automotive batteries stored on a concrete floor do not discharge faster than they would on other surfaces. Most modern automotive batteries are sealed and do not leak battery acid when properly stored, although the sulfuric acid in them can leak out and stain, etch, or corrode concrete floors if their cases crack or tip over or their vent-holes are breached by floods. Building new roads, or widening existing ones, does not always reduce congestion. Sometimes it can make the congestion worse.

== Further reading == Baena-Cagnani CE (2001). "Desloratadine activity in concurrent seasonal allergic rhinitis and asthma". Allergy. 56 Suppl 65: 21–7. doi:10.1111/j.1398-9995.2001.00001.x-i1. PMID 11243501. Devillier P, Roche N, Faisy C (2008). "Clinical pharmacokinetics and pharmacodynamics of desloratadine, fexofenadine and levocetirizine : a comparative review". Clinical Pharmacokinetics. 47 (4): 217–30. doi:10.2165/00003088-200847040-00001. PMID 18336052. Geha RS, Meltzer EO (April 2001). "Desloratadine: A new, nonsedating, oral antihistamine". The Journal of Allergy and Clinical Immunology. 107 (4): 751–62. doi:10.1067/mai.2001.114239. PMID 11295678. Henz BM (2001). "The pharmacologic profile of desloratadine: a review". Allergy. 56 Suppl 65: 7–13. doi:10.1034/j.1398-9995.2001.00101.x. PMID 11243504.

Sources: en.wikipedia.org

Background from the literature

=== 90Sr === Strontium-90 has been used by the Soviet Union in terrestrial RTGs. 90Sr decays by β− decay into 90Y, which quickly β-decays again. It has a lower decay energy than 238Pu, but its shorter half-life of 28.8 years and lower atomic weight yield a power density for pure metal of 0.95 watts per gram. As 90Sr is a very reactive alkaline earth metal and a bone seeker that accumulates in bone-tissue due to its chemical similarity to calcium (once in the bones it can significantly damage the bone marrow, a rapidly dividing tissue), it is usually not used in pure form in RTGs. The most common form is the perovskite strontium titanate (SrTiO3) which is chemically nigh-inert and has a high melting point. While its Mohs hardness of 5.5 has made it ill-suited as a diamond simulant, it is of sufficient hardness to withstand some forms of accidental release from its shielding without too fine dispersal of dust. The downside to using SrTiO3 instead of the native metal is it reduces power density, as the TiO3 part of the material does not produce any decay heat. 90Sr has a high fission product yield in the fission of both 235U and 239Pu and is thus available in large quantities at a relatively low price if extracted from spent nuclear fuel. Starting from the oxide or the native metal, one pathway to obtaining SrTiO3 is to let it transform to strontium hydroxide in aqueous solution, which absorbs carbon dioxide from air to become less soluble strontium carbonate.

Second messengers are intracellular signaling molecules released by the target cell in response to exposure to extracellular signaling molecules—the first messengers. (Intercellular signals, a non-local form of cell signaling, encompassing both first messengers and second messengers, are classified as autocrine, juxtacrine, paracrine, and endocrine signaling depending on the range of the signal.) Second messengers trigger physiological changes at cellular level such as proliferation, differentiation, migration, survival, apoptosis and depolarization. They are one of the triggers of intracellular signal transduction cascades. Examples of second messenger molecules include cyclic AMP, cyclic GMP, inositol triphosphate, diacylglycerol, and calcium. First messengers are extracellular factors, often hormones or neurotransmitters, such as epinephrine, growth hormone, and serotonin. Because peptide hormones and neurotransmitters typically are biochemically hydrophilic molecules, these first messengers may not physically cross the phospholipid bilayer to initiate changes within the cell directly—unlike steroid hormones, which usually do. This functional limitation requires the cell to have signal transduction mechanisms to transduce first messenger into second messengers, so that the extracellular signal may be propagated intracellularly. An important feature of the second messenger signaling system is that second messengers may be coupled downstream to multi-cyclic kinase cascades to greatly amplify the strength of the original first messenger signal.

=== Microtox Omni software === The Microtox Omni software was developed by Azur Environmental and allows users of the Microtox Model 500 analyser to run tests, visualize data, calculate statistics and generate reports. This program contains a set of templates for all of the commonly used toxicity tests and allows you to modify or add to the provided templates. The modification of these templates allows for the production of new test formats not originally included with the software. The test templates that are included in this software define all of the parameters for a particular test method. This program calculates the most efficient way of setting up the desired test on the Model 500 Analyser. A test tutor is also included with Microsoft Omni that gives listed instructions on how to set up and run the test of interest. This software allows users to load files from previous versions of the Microtox DOS Software and also gives users the ability to save new data in that original format. A database is included in this software that grants users to access data from a number of other users and test sites, allowing for a comparison of data and trend changes over time. Microtox Omni can be used with any number of databases.

Petrus Mailo (27 December 1902 – 12 September 1971) was a Micronesian chief and politician. He served as chief and mayor of Moen from 1944 and was a member of both the Truk Congress and the House of Representatives of the Trust Territory of the Pacific Islands.

== In popular culture == In Jules Verne's 1870 novel, 20,000 Leagues Under The Sea, the story is written in the form of narration from journal entries by Professor Pierre Aronnax, a naturalist from the Paris Museum of Natural History (the name of the museum at the time). The Gallery of Palaeontology and Comparative Anatomy and other parts of Jardin des Plantes was a source of inspiration for French graphic novelist Jacques Tardi. The gallery appears on the first page and several subsequent pages of Adèle et la bête (Adèle and the Beast; 1976), the first album in the series of Les Aventures extraordinaires d'Adèle Blanc-Sec. The story opens with a 136-million-year-old pterodactyl egg hatching, and a live pterodactyl escaping through the gallery glass roof, wreaking havoc and killing people in Paris. The Gallery of Palaeontology and Comparative Anatomy returned the favour by placing a life size cardboard cutout of Adèle and the hatching pterodactyl in a glass cabinet outside the main entrance on the top floor balcony. The Pulitzer Prize–winning novel All the Light We Cannot See, by Anthony Doerr, partially takes place at the MNHN; the father of the protagonist Marie-Laure works as the chief locksmith of the museum. The story also makes many references to Jules Verne's novel 20,000 Leagues Under the Seas, and the fictional naturalist and narrator Professor Pierre Aronnax. Marie-Laure was gifted braille books of the novel by her father.

Sources: en.wikipedia.org

Reference notes

== Early life and education == Gabe Logan Newell was born on November 3, 1962, at Aspen Valley Hospital in Aspen, Colorado, as the son of Donald Newell. He attended Davis Senior High School in Davis, California. He began computer programming in high school, at a time when programming was not an established career path, and imagined he would become a doctor. He worked as a paperboy, and later a telegram messenger for Western Union. In 1980, Newell enrolled at Harvard University to study programming.

Synthetic biology generally falls under existing regulations for GMOs and biotechnology in general, and any regulations that exist for downstream commercial products, although there are generally no regulations in any jurisdiction that are specific to synthetic biology.

== External links == "Regulation of endosomal clathrin and retromer-mediated endosome to Golgi retrograde transport by the J-domain protein RME-8" - The EMBO Journal "Pleiotropic effects of purine auxotrophy inRhizobium meliloti on cell surface molecules" - Springerlink "Auxotrophy and Organic Compounds in the Nutrition of Marine Phytoplankton"

Mark Salisbury of Time Out wrote of the lead acting to be "excellent" and the crowd scenes "astonishing", while equally observing how the climax was "truly nerve-wracking". He called it "an implacable work of authority and compassion, Cry Freedom is political cinema at its best." James Sanford, however, writing for the Kalamazoo Gazette, did not appreciate the film's qualities, calling it "a Hollywood whitewashing of a potentially explosive story." Rating the film with 3 Stars, critic Leonard Maltin wrote that the film was a "sweeping and compassionate film". He did, however, note that the film "loses momentum as it spends too much time on Kline and his family's escape from South Africa". But in positive followup, he pointed out that it "cannily injects flashbacks of Biko to steer it back on course." John Simon of the National Review called Cry Freedom "grandiosely inept". In 2013, the movie was one of several discussed by David Sirota in Salon in an article concerning white saviour narratives in film.

Sources: en.wikipedia.org

Frequently asked questions

Is cardarine approved for human use?

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.

Why is cardarine banned in sport?

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.

What is the difference between cardarine and GW501516?

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.

What is the main molecular target of cardarine?

It targets PPARδ, a nuclear receptor involved in lipid and energy metabolism. It does not act primarily on androgen receptors. This distinction separates it from SARMs.

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