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Background And Regulatory Status — Research Overview

By Editorial Desk · published 2026-02-10 · last reviewed 2026-03-02 · Blog

PPARδ agonist comes up often in conversation and rarely with the context attached. Here we lay out the basics in order, then work through the practical considerations.

Last reviewed on 2026-03-02. 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.

Cardarine Identity and Mechanism

Published literature on cardarine includes in vitro assays, rodent experiments, and a small number of human studies. Reports describe effects on exercise capacity and lipid metabolism in animals, while human evidence is sparse. Many online descriptions present the compound as a proven endurance aid, a claim not supported by regulatory approval or large clinical trials. Analytical studies focus on identifying the parent compound and its metabolites in biological samples. Important uncertainties include species differences, dose-response relationships, and the relevance of rodent tumor findings to humans.

Cardarine is the common name for GW501516, a synthetic compound studied as a peroxisome proliferator-activated receptor delta agonist. Researchers developed it to explore treatments for lipid disorders and metabolic conditions. It is not an approved medicine in any country. Early clinical work examined changes in HDL cholesterol and triglycerides, but development was discontinued after animal studies raised concerns about cancer. The compound remains available as a research chemical and appears in discussions of performance enhancement.

At the molecular level, GW501516 binds and activates PPARδ, a nuclear receptor that regulates transcription. Activation shifts expression of genes involved in fatty acid oxidation, energy expenditure, and lipid transport in skeletal muscle and liver. Animal studies report increased endurance and altered lipid profiles after exposure. Human data are limited to small trials and do not establish long-term safety or efficacy. PPARδ also has roles in cell proliferation, so the relationship between activation and cancer risk remains an open question.

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

Cardarine as Investigational PPARδ Agonist

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.

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.

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Detection, Stability, and Quality

Quality assessment for cardarine samples usually combines identity, purity, and impurity testing. Nuclear magnetic resonance spectroscopy and mass spectrometry can confirm molecular structure, while high-performance liquid chromatography estimates purity. Certificates of analysis from testing laboratories may list these results, but they do not establish safety or legality. In the absence of approved manufacturing, products sold online may contain the wrong compound, variable amounts, or unlisted contaminants. Independent verification is therefore central to analytical work and to interpreting any reported biological activity.

Laboratory detection of GW501516 commonly uses liquid chromatography coupled with tandem mass spectrometry. The method can identify the parent compound or its metabolites in urine and blood after sample cleanup. Protein precipitation, solid-phase extraction, or enzymatic hydrolysis may precede analysis, depending on the matrix. Reference standards are required for accurate quantification and confirmation. Because the compound is not approved, testing often occurs in anti-doping, forensic, or research settings rather than routine clinical care. Results are reported with limits of detection and quantification.

Mechanism and Laboratory Detection

Published human data are sparse and mostly come from early-phase trials. Those studies examined short-term changes in lipids, glucose, and exercise capacity, but they were not large enough to establish efficacy or long-term safety. Some animal experiments reported increased running endurance, yet such findings do not prove a performance benefit in people. Anti-doping laboratories detect GW501516 and its metabolites in urine or blood using liquid chromatography-tandem mass spectrometry. Detection windows depend on dose, sample type, and individual metabolism. The method is sensitive enough to identify trace residues in tested samples.

Laboratory handling focuses on identity, purity, and stability. Reference standards are typically stored cold and dry, protected from light, because solutions can degrade over time. Analytical checks may use high-performance liquid chromatography with ultraviolet detection or mass spectrometry. Impurities and related substances can be separated chromatographically and compared with a known standard. Because cardarine is not an approved drug, compendial monographs are absent, and laboratories often rely on in-house methods. Reported purity varies among unregulated products and should not be assumed from a label.

Notes from published material

During the development of B cells, the immunoglobulin gene undergoes sequences of rearrangements that lead to formation of the antibody repertoire. For example, in the early stages of transition from pro-B cell to pre-B cell, a partial rearrangement of the heavy-chain gene occurs which is followed by complete rearrangement of heavy-chain gene. At this stage (Pre-B cell), the μ heavy chain and surrogate light chain are formed. The final rearrangement of the light chain gene generates immature B cell and membrane-bound IgM (mIgM). The process explained here occurs during development of naïve B cells, prior to exposure to exogenous antigens. The mature B cell formed as a result of these processing changes leaves the bone marrow and may then be stimulated by an antigen to develop into antibody-secreting plasma cells. Also at first, the mature B cell expresses membrane-bound IgD and IgM. These two classes could switch to secretory IgD and IgM during the processing of mRNAs. Finally, further class switching follows as the cell continues to divide and differentiate. For instance, a B cell expressing IgM can switch to IgG, IgA, or IgE depending on the stimulus provided (which may be dependent upon the antigenic source and the responding immune cells).

=== Formation === 232Th is a primordial nuclide formed in the r-process, which probably occurs in supernovae and neutron star mergers. These violent events scattered it across the galaxy. The letter "r" stands for "rapid neutron capture", and occurs in core-collapse supernovae, where heavy seed nuclei such as 56Fe rapidly capture neutrons, running up against the neutron drip line, as neutrons are captured much faster than the resulting nuclides can beta decay back toward stability. Neutron capture is the only way for stars to synthesise elements beyond iron because of the increased Coulomb barriers that make interactions between charged particles difficult at high atomic numbers and the fact that fusion beyond 56Fe is endothermic. Because of the abrupt loss of stability past 209Bi, the r-process is the only process of stellar nucleosynthesis that can create thorium and uranium; all other processes are too slow and the intermediate nuclei alpha decay before they capture enough neutrons to reach these elements.

A lethal autonomous weapon is a machine that locates, selects and engages human targets without human supervision. Widely available AI tools can be used by bad actors to develop inexpensive autonomous weapons and, if produced at scale, they are potentially weapons of mass destruction. Even when used in conventional warfare, they currently cannot reliably choose targets and could potentially kill an innocent person. In 2014, 30 nations (including China) supported a ban on autonomous weapons under the United Nations' Convention on Certain Conventional Weapons, however the United States and others disagreed. By 2015, over fifty countries were reported to be researching battlefield robots.

The 1939 Molotov–Ribbentrop Pact, a non-aggression agreement between Nazi Germany and the Soviet Union, had left the KSČ in disarray. But ever faithful to the Soviet line, the KSČ began a more active struggle against the Germans after Operation Barbarossa, Germany's attack on the Soviet Union in June 1941.

=== Safety === The gap between recommended daily intake and what are considered safe upper limits (ULs) can be small. For example, for calcium the U.S. Food and Drug Administration set the recommended intake for adults over 70 years at 1,200 mg/day and the UL at 2,000 mg/day. The European Union also sets recommended amounts and upper limits, which are not always in accord with the U.S. Likewise, Japan, which sets the UL for iodine at 3000 μg versus 1100 for the U.S. and 600 for the EU. In the table above, magnesium appears to be an anomaly as the recommended intake for adult men is 420 mg/day (women 350 mg/day) while the UL is lower than the recommended, at 350 mg. The reason is that the UL is specific to consuming more than 350 mg of magnesium all at once, in the form of a dietary supplement, as this may cause diarrhea. Magnesium-rich foods do not cause this problem.

Sources: en.wikipedia.org

Background from the literature

=== Drug policy === As part of the US-led war on drugs, Peru has historically pursued a coca-eradication policy. However, during his electoral campaign, Pedro Castillo pledged to expel DEA agents from Peru. In April 2021, under then President Francisco Sagasti, coca eradication operations in the VRAEM were suspended. In September, following Castillo's inauguration, coca eradication was resumed in all areas except the VRAEM, which is the area with the most coca cultivation. Under the Vásquez cabinet, Interior Minister Luis Barranzuela was asked whether he ordered Coca eradication to be suspended in the VRAEM, which he denied. Barranzuela also said that the Interior Ministry has no influence on Devida, the agency in charge of anti-drug policy. Later, the Free Peru caucus proposed to legalize the commercialization and industrial cultivation of the coca leaf. Currently, coca leaf consumption is allowed for "traditional purposes." The proposed bill would also declare the coca leaf "the natural heritage of the nation." Prime Minister Mirtha Vásquez claimed that coca farmers are "fed up" with the permanent cycle of coca eradication and replantation. Vásquez stated that she would pursue binding agreements with legal coca producers while cracking down on drug trafficking. On 19 November 2021, the new Interior Minister Avelino Guillén pledged to increase the eradication of coca crops.

== Early life and education == Strahl was born in Buffalo, New York and raised in Albuquerque, New Mexico. He moved to Chapel Hill, North Carolina in 1980 when his father went to medical school at the University of North Carolina at Chapel Hill. Strahl entered the University of North Carolina at Greensboro in 1988, where he double majored in Chemistry and Biology. Strahl joined the Department of Biochemistry at North Carolina State University and received his PhD in 1998 under the supervision of Dr. William L. Miller. At North Carolina State University, Strahl defined mechanisms for how the Follicle-Stimulating Hormone-Beta (FSHß) gene is regulated at the transcriptional level. In 1998, Strahl performed postdoctoral studies under the mentorship of Dr. C. David Allis at the University of Virginia’s Department of Biochemistry and Molecular Genetics.

μ-Opioid receptor (MOR): extremely high affinity partial agonist: at low doses, the MOR-mediated effects of buprenorphine are comparable to those of other narcotics, but these effects reach a "ceiling" as the receptor population is saturated. This behavior is responsible for several unique properties: buprenorphine greatly reduces the effect of most other MOR agonists, can cause precipitated withdrawal when used in actively opioid dependent persons, and has a lower incidence of respiratory depression relative to full MOR agonists. κ-Opioid receptor (KOR): High affinity antagonist/weak partial agonist —this activity is hypothesized to underlie some of the effects of buprenorphine on mood disorders and addiction. δ-Opioid receptor (DOR): High affinity antagonist Nociceptin receptor (NOP, ORL-1): Weak affinity, very weak partial agonist In simplified terms, buprenorphine can essentially be thought of as a nonselective, mixed agonist–antagonist opioid receptor modulator, acting as an unusually high affinity, weak partial agonist of the MOR, a high affinity antagonist of the KOR and DOR, and a relatively low affinity, very weak partial agonist of the ORL-1/NOP. Although buprenorphine is a partial agonist of the MOR, human studies have found that it acts like a full agonist with respect to analgesia in opioid-intolerant individuals. Conversely, buprenorphine behaves like a partial agonist of the MOR with respect to respiratory depression. Buprenorphine is also known to have high binding affinity with antagonistic activity at the putative ε-opioid receptor.

In transgender women, breast development is a desired effect of antiandrogen and/or estrogen treatment. Bicalutamide induces breast development in individuals assigned male at birth by two mechanisms: 1) blocking androgen signaling in breast tissue; and 2) increasing estrogen levels. Estrogen is responsible for the induction of breast development under normal circumstances, while androgens powerfully suppress estrogen-induced breast growth. It has been found that very low levels of estrogen can induce breast development in the presence of low or no androgen signaling. In accordance, not only does bicalutamide induce gynecomastia at a high rate when given as a monotherapy to men with prostate cancer (38–85%; 66% in one very large trial), similarly to high-dose estrogen therapy with diethylstilbestrol (41–77%), NSAAs have been found to result in a higher incidence of gynecomastia in combination with a GnRH analogue (13–25%) relative to GnRH analogue therapy or castration alone (1–16%) (in spite of the presence of only castrate levels of estrogen in both cases). The rate of gynecomastia with CAB is also higher than with CPA monotherapy (7%). A study of men treated with NSAA (flutamide or bicalutamide) monotherapy for prostate cancer found that NSAAs induced full ductal development and moderate lobuloalveolar development of the breasts from a histological standpoint.

Sources: en.wikipedia.org

Reference notes

=== Muchik linguistic evidence and Moche consumption === During the pre-Columbian era, the Moche culture (or Mochica), which inhabited the northern coast of Peru, actively collected and consumed the fruits of Solanum pimpinellifolium. Unlike the common domesticated tomato (Solanum lycopersicum), which lacks native names of Andean origin because its final domestication occurred in Mesoamerica, S. pimpinellifolium was integrated early into the local lexicon of the region. In the ancient Muchik language, the plant and its fruit were called faña (translated as "tender plant"), a designation recovered in modern philological research on the pre-Hispanic speech of the area.

== Human genes == 45S: RNR1, RNR2, RNR3, RNR4, RNR5; (unclustered) RNA18SN1, RNA18SN2, RNA18SN3, RNA18SN4, RNA18SN5, RNA28SN1, RNA28SN2, RNA28SN3, RNA28SN4, RNA28SN5, RNA45SN1, RNA45SN2, RNA45SN3, RNA45SN4, RNA45SN5, RNA5-8SN1, RNA5-8SN2, RNA5-8SN3, RNA5-8SN4, RNA5-8SN5 5S: RNA5S1, RNA5S2, RNA5S3, RNA5S4, RNA5S5, RNA5S6, RNA5S7, RNA5S8, RNA5S9, RNA5S10, RNA5S11, RNA5S12, RNA5S13, RNA5S14, RNA5S15, RNA5S16, RNA5S17 Mt: MT-RNR1, MT-TV (co-opted), MT-RNR2

=== Detector === In GPC, the concentration by weight of polymer in the eluting solvent may be monitored continuously with a detector. There are many detector types available and they can be divided into two main categories. The first is concentration sensitive detectors which includes UV-VIS absorption, differential refractometer (DRI) or refractive index (RI) detectors, infrared (IR) absorption and density detectors. The second category is molecular weight sensitive detectors, which include low angle light scattering detectors (LALLS) and multi angle light scattering (MALS). The resulting chromatogram is therefore a weight distribution of the polymer as a function of retention volume. The most sensitive detector is the differential UV photometer and the most common detector is the differential refractometer (DRI). When characterizing copolymer, it is necessary to have two detectors in series. For accurate determinations of copolymer composition at least two of those detectors should be concentration detectors. The determination of most copolymer compositions is done using UV and RI detectors, although other combinations can be used.

=== Superhydrophobicity === The simple adjustment of pore morphology and geometry of porous silicon also offers a convenient way to control its wetting behavior. Stable ultra- and superhydrophobic states on porous silicon can be fabricated and used in lab-on-a-chip, microfluidic devices for the improved surface-based bioanalysis.

A study that follows a group of people over time who have, or are at risk of developing, a specific medical condition or disease. A natural history study collects health information in order to understand how the medical condition or disease develops and how to treat it. (NCI) Study of the natural development of something (such as an organism or a disease) over a period of time. (NLM) New Drug Application (NDA)

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 cardarine?

Cardarine is a common name for the investigational compound GW501516. It acts as a PPARδ agonist and is not approved for human use. It is prohibited in sport.

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