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Background And Regulatory History — Quick Reference

By Editorial Desk · published 2025-12-24 · last reviewed 2026-01-12 · Topic

The short version of prohibited list fits in a sentence. The long version — which is the one that helps — is below.

This page was last updated on 2026-01-12 and is reviewed periodically as new material appears.

Background and Regulatory History

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.

Regulation and Analytical Detection

Anti-doping laboratories detect GW501516 and its metabolites using liquid chromatography-tandem mass spectrometry. Urine is the most common matrix, though blood and dried blood spots may also be used in some programs. Detection depends on factors such as dose, timing, metabolism, and the sensitivity of the assay. Published methods describe limits of detection in the low nanogram per milliliter range for related compounds. Exact detection windows are not fixed for all situations and remain an area of ongoing study.

Products sold as cardarine have been found to contain incorrect compounds, variable amounts, or no active ingredient at all. Independent testing is required to verify identity and purity. Common analytical approaches include high-performance liquid chromatography, mass spectrometry, and nuclear magnetic resonance for structural confirmation. These methods can distinguish GW501516 from related PPAR agonists and from unrelated steroids. For regulators and researchers, such verification is central to interpreting both biological results and adverse event reports.

Cardarine at a glance

PropertyValueNotes
Common nameCardarineCommon internet and media name.
Research codeGW501516Also written GW-1516.
Drug classPPARδ agonistNot a selective androgen receptor modulator.
Development statusDiscontinuedClinical development halted after rodent cancer findings.
Regulatory statusProhibited in sportListed by WADA; not approved as medicine.

Identity and Pharmacological Classification

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.

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.

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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.

Cardarine as Investigational PPARδ Agonist

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.

Background from the literature

== Genetics and disease relevance == In humans, enteropeptidase is encoded by the TMPRSS15 gene (also known as ENTK, and previously as PRSS7) on chromosome 21q21. Some nonsense and frameshift mutations in this gene lead to a rare recessive disorder characterised by severe failure to thrive in affected infants, due to enteropeptidase deficiency. Enteropeptidase mRNA expression is limited to the proximal small intestine, and the protein is found in enterocytes of duodenum and proximal jejunum. Upon secretion from the pancreas into the duodenum, trypsinogen encounters enteropeptidase and is activated. Trypsin then cleaves and activates other pancreatic serine protease zymogens (chymotrypsinogen and proelastases), metalloprotease zymogens (procarboxypeptidases) and prolipases. By means of this simple two-step cascade, the destructive activity of these digestive hydrolases is confined to the lumen of the intestine. The physiological importance of this pathway is demonstrated by the severe intestinal malabsorption caused by congenital deficiency of enteropeptidase. This condition can be life-threatening, but responds to oral supplementation with pancreatic extract.

=== Autonomic neuropathy === During hypoglycemia, the body normally releases epinephrine (more commonly known as adrenaline) and related substances. This serves two purposes: The β-effect of epinephrine is responsible for the palpitations and tremors, giving the patient warning that hypoglycemia is present. The β-effect of epinephrine also stimulates the liver to release glucose (gluconeogenesis and glycogenolysis). In other words, the epinephrine warns the patient that hypoglycemia is present and signals the liver to release glucose to reverse it. In the absence of epinephrine release, or when it is attenuated (reduced) during hypoglycemia, the patient may not be aware that his/her glucose level is low. This is termed 'hypoglycemic unawareness'. The problem is compounded since, in the absence of an appropriate epinephrine response, the usual responses of glycogenolysis and gluconeogenesis may also be lost or blunted. Since epinephrine release is a function of the autonomic nervous system, the presence of autonomic neuropathy (i.e., a damaged autonomic nervous system) will cause the epinephrine release in response to hypoglycemia to be lost or blunted. Unfortunately, damage to the autonomic nervous system in the form of autonomic neuropathy is a common complication of long-standing diabetes (especially type 1 diabetes), so the presence of hypoglycemic unawareness may be a sign of autonomic neuropathy, although the autonomic response to hypoglycemia is already impaired in patients with type 1 diabetes mellitus even in the absence of autonomic neuropathy.

== Binding change mechanism == The binding change mechanism, proposed by Paul Boyer and John E. Walker, who were awarded the Nobel Prize in Chemistry in 1997, suggests that ATP synthesis is linked to a conformational change in ATP synthase. This change is triggered by the rotation of the gamma subunit. ATP synthesis can be achieved through several mechanisms. The first mechanism postulates that the free energy of the proton gradient is utilized to alter the conformation of polypeptide molecules in the ATP synthesis active centers. The second mechanism suggests that the change in the conformational state is also produced by the transformation of mechanical energy into chemical energy using biological mechanoemission, a process in which energy or particles (e.g., photons or ions) are emitted from a mitochondrion when it is mechanically stimulated.

== Early life and career == Cantelmo was a high school valedictorian. He graduated from Yale University with a degree in molecular biophysics and biochemistry. He worked for about 35 years in the pharmaceutical industry, specializing in high-performance liquid chromatography (HPLC). According to his own accounts and those of family members, he ran three HPLC companies. The last of these was GL Sciences. He left that position prior to the events of 2019. GL Sciences has stated it has no association with Cantelmoism or the use of illegal drugs. Cantelmo had a history of mental health difficulties and prior suicide attempts. He had also used other substances, including mescaline, LSD, and methamphetamine, at earlier points in his life.

Sources: en.wikipedia.org

Reference notes

Hox genes A subset of highly conserved homeobox-containing genes whose protein products function as transcription factors essential for the proper organization of the body plan in developing animal embryos, ensuring that the correct structures are formed in the correct places. Hox genes are usually arranged on a chromosome in tandem arrays and are expressed sequentially during development, with the sequence of gene activation corresponding to their physical arrangement within the genome and/or the physical layout of the tissues in which they are expressed along the organism's anterior–posterior axis.

Nixon and Kissinger played a "good cop-bad cop" routine with Dobrynin, with Nixon acting the part of the petulant president at the end of his patience with North Vietnam, while Kissinger acted as the reasonable diplomat anxious to improve relations with the Soviet Union, saying to Dobrynin in May 1969 that Nixon would "escalate the war" if the Soviet Union "didn't produce a settlement" in Vietnam. At another meeting in 1969, Kissinger warned Dobrynin that "the train has just left the station and is now headed down the track", saying the Soviet Union better start pressuring North Vietnam now before Nixon did something truly reckless and dangerous. The attempt at "linkage" failed as the Soviet Union did not pressure North Vietnam and instead Dobrynin told Kissinger that the Soviets wanted better relations with the United States regardless of the Vietnam War. After the failure of the "linkage" attempt, Nixon became more open to the alternative strategy suggested by the Defense Secretary Melvin Laird who argued that the burden of the war should be shifted to the South Vietnamese, which was initially called "de-Americanization" and which Laird renamed Vietnamization because it sounded better.

Abnormal cells on the blood smear might indicate acute leukaemia or lymphoma, while an abnormally high count of neutrophils or lymphocytes, in combination with indicative symptoms and blood smear findings, may raise suspicion of a myeloproliferative disorder or lymphoproliferative disorder. Examination of the CBC results and blood smear can help to distinguish between causes of anemia, such as nutritional deficiencies, bone marrow disorders, acquired hemolytic anemias and inherited conditions like sickle cell anemia and thalassemia. The reference ranges for the complete blood count represent the range of results found in 95% of apparently healthy people. By definition, 5% of results will always fall outside this range, so some abnormal results may reflect natural variation rather than signifying a medical issue. This is particularly likely if such results are only slightly outside the reference range, if they are consistent with previous results, or if there are no other related abnormalities shown by the CBC. When the test is performed on a relatively healthy population, the number of clinically insignificant abnormalities may exceed the number of results that represent disease. For this reason, professional organizations in the United States, United Kingdom and Canada recommend against pre-operative CBC testing for low-risk surgeries in individuals without relevant medical conditions. Repeated blood draws for hematology testing in hospitalized patients can contribute to hospital-acquired anemia and may result in unnecessary transfusions.

=== Characterization and analysis === Esters are generally identified by gas chromatography, taking advantage of their volatility. IR spectra for esters feature an intense sharp band in the range 1730–1750 cm−1 assigned to νC=O. This peak changes depending on the functional groups attached to the carbonyl. For example, a benzene ring or double bond in conjunction with the carbonyl will bring the wavenumber down about 30 cm−1.

=== Structure === Scaffolds are used in tissue engineering to create an environment with similar mechanical properties of the native tissue. Scaffolds must be biocompatible and have high compressive strength. Scaffolds can be created from hydrogels, polymers or other material. Hydrogels are lightly cross-linked polymer networks swollen with water. Degree of crosslinking, porosity, and polymer composition can be tuned to create a hydrogel with similar properties to native cartilage. Researchers have been exploring the use of hydrogels as a cartilage substitute since the 1970s.

Sources: en.wikipedia.org

Notes from published material

Weigert's hematoxylin is a sequence of three solutions: ferric chloride in diluted hydrochloric acid, hematoxylin in 95% ethanol, and potassium ferricyanide solution alkalized by sodium borate. It is used to stain the nuclei. Solution A, also called plasma stain, contains acid fuchsin, Xylidine Ponceau, glacial acetic acid, and distilled water. Other red acid dyes can be used, e.g. the Biebrich scarlet in Lillie's trichrome. Solution B contains phosphomolybdic/phosphotungstic acid in distilled water. Solution C, also called fibre stain, contains Light Green SF yellowish, or alternatively Fast Green FCF. It is used to stain collagen. If blue is preferred to green, methyl blue or water blue can be substituted. Standard applications: Masson's trichrome staining is widely used to study muscular pathologies (muscular dystrophy), cardiac pathologies (infarct), hepatic pathologies (cirrhosis) or kidney pathologies (glomerular fibrosis). It can also be used to detect and analyze tumors on hepatic and kidney biopsies.

Kr + F2 → KrF2 Krypton gas in a krypton fluoride laser absorbs energy from a source, causing the krypton to react with fluorine gas, producing the exciplex krypton fluoride, a temporary complex in an excited energy state:

== Brumation == In the colder winter months, some rattlesnake species enter a period of brumation, which is dormancy similar to hibernation. They often gather for brumation in large numbers, sometimes over 1,000 snakes, and huddle together inside underground "rattlesnake dens" or hibernacula. They regularly share their winter burrows with a wide variety of other species (such as turtles, small mammals, invertebrates, and other types of snakes). Rattlesnakes often return to the same den every year, sometimes traveling several miles to get there. How the rattlesnakes find their way back to the dens each year is unknown, but it may involve a combination of pheromone trails and visual cues such as topography, celestial navigation, and solar orientation. Species with long periods of brumation tend to have much lower reproductive rates than those with shorter brumation periods or those that do not brumate at all. Female timber rattlesnakes in high peaks in the Appalachian Mountains of New England reproduce every three years on average; the lance-headed rattlesnake (C. polystictus), native to the warm climate of Mexico, reproduces annually. Like most other snakes, rattlesnakes aestivate during very hot or dry periods, which is why they are rarely seen during the hottest and driest months of summer.

== Medical uses == Eladocagene exuparvovec is indicated for the treatment of aromatic L-amino acid decarboxylase (AADC) deficiency. Aromatic L-amino acid decarboxylase deficiency is a rare genetic disorder that affects the production of some neurotransmitters, which are chemical messengers that allow cells in the body's nervous system to communicate with each other. Affected individuals may experience symptoms such as delays in gross motor function (head control, sitting, standing, and walking), hypotonia (weak muscle tone), and developmental and cognitive delays.

On 13 September 1945, a Franco-British task force landed in Java, main island of the Dutch East Indies (for which independence was being sought by Sukarno), and Saigon, capital of Cochinchina (southern part of French Indochina), both being occupied by the Japanese under Field Marshal Hisaichi Terauchi, Commander-in-Chief of Japan's Southern Expeditionary Army Group based in Saigon. Allied troops in Saigon were an airborne detachment, two British companies of the Indian 20th Infantry Division and the French 5th Colonial Infantry Regiment, with British General Sir Douglas Gracey as supreme commander. The latter proclaimed martial law on September 21, and Franco-British troops took control of Saigon.

Sources: en.wikipedia.org

Frequently asked questions

Is cardarine a selective androgen receptor modulator?

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.

Why did clinical development stop?

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.

Is cardarine approved for medical use?

No. It remains an investigational compound without approved therapeutic labeling. Sports regulators prohibit its use, and health agencies have warned against consuming it.

Is cardarine legal to buy?

Legal status varies by country, but cardarine is not approved as a medicine in major jurisdictions. It is often sold as a research chemical, a category that may not be lawful for human use. Buyers should check local laws and product labels carefully.

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