This is a working overview of Nuclear receptor, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2025-12-04 and is reviewed periodically as new material appears.
Cardarine can be detected in biological samples and product materials using liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). The method separates compounds by chromatography and identifies them by mass-to-charge transitions, allowing low-level detection in urine or blood. Sample preparation often involves enzymatic hydrolysis, solid-phase extraction, or protein precipitation. Certified reference materials and isotope-labeled internal standards improve quantification. Detection windows depend on metabolism, matrix, and assay sensitivity, so no single universal window applies.
Regulatory treatment of cardarine differs by context and jurisdiction. In competitive sport, the World Anti-Doping Agency lists PPARδ agonists, including GW501516, as prohibited at all times. Outside sport, it lacks approval as a prescription medicine in major drug markets, and products sold for human consumption may be treated as unapproved drugs. Some countries also restrict importation or sale through general consumer protection and medicines laws. These classifications affect availability, testing, and legal risk without establishing therapeutic value.
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.
| Property | Value | Notes |
|---|---|---|
| WADA classification | S4 Hormone and Metabolic Modulators | Prohibited at all times in sport. |
| Drug approval status | Not approved in major jurisdictions | No accepted therapeutic indication. |
| Common detection method | LC-MS/MS | Detects parent compound and metabolites. |
| Typical test matrix | Urine or blood | Urine is common in anti-doping testing. |
| Product labeling | Research chemical or supplement | Often not independently verified. |
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.
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 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.
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.
== H == Habituation A form of non-associative learning in which an organism decreases or ceases its responses to a repetitive, harmless stimulus over time. Hallucination A perception in the absence of external stimulus, such as hearing voices or seeing things that are not present. Common in conditions like schizophrenia or sensory deprivation. Hemispheres of the brain The two symmetrical halves of the brain—left and right—that control opposite sides of the body. Each hemisphere has specialized functions but works in coordination with the other. Hemispatial neglect A neuropsychological condition in which a person fails to attend to one side of space, usually the left, following damage to the right parietal lobe. Hering’s law of equal innervation A principle in ocular motor control stating that yoked eye muscles receive equal neural signals to maintain coordinated binocular eye movements. Hertz (Hz) A unit of frequency equal to one cycle per second. Used in neuroscience to describe brain wave activity, neural firing rates, and oscillations. Hindbrain The posterior part of the brain, including the medulla oblongata, pons, and cerebellum. It regulates vital autonomic functions and coordinates movement. Hippocampus A brain structure located in the medial temporal lobe, critical for memory formation, spatial navigation, and learning. Damage is associated with anterograde amnesia. Histamine A neurotransmitter involved in arousal, wakefulness, and inflammatory responses. Histaminergic neurons are primarily located in the hypothalamus.
== Legacy == After the end of the Cold War in 1991, the assets of the USSR's space program passed mainly to Russia. Since then, the United States and Russia have cooperated in space with the Shuttle-Mir Program, and the International Space Station (ISS). The Russians continue to use their R-7 rocket family as their orbital workhorse to launch the Soyuz crewed spacecraft and its Progress derivative uncrewed cargo craft as shuttles to the ISS. After the 2011 retirement of the Space Shuttle, American crews were dependent on the R-7–Soyuz to reach the ISS, until the 2020 first flight of the US Crew Dragon Commercial Crew Development vehicle. In 2023 the Russian Federation resumed the Luna missions as a part of the Luna-Glob programme with the launch of Luna 25 (47 years after the Soviet Luna 24), amidst American reignition of interest in the Moon with the Artemis program beginning with the launch of Artemis I in 2022. Some of this competitiveness is part of the New Space Race.
== Bibliography == Wink, M (2009). "Mode of action and toxicology of plant toxins and poisonous plants". Mitt. Julius Kühn-Inst. 421: 93–112. Archived from the original on 18 March 2014. Retrieved 18 March 2014.
Sources: en.wikipedia.org
=== Function === Endocannabinoids act as lipid messengers, released from one cell to activate cannabinoid receptors on nearby cells. Unlike monoamine neurotransmitters, they are lipophilic, insoluble in water, and synthesized on-demand rather than stored. They act locally due to their hydrophobic nature, unlike hormones. The endocannabinoid 2-AG is found in bovine and human maternal milk. Cannabinoids enhance sweet taste by increasing Tlc1 receptor expression and suppressing leptin, impacting energy homeostasis.
== Function == The protein encoded by this gene contains a leucine-rich repeat and a death domain. This protein has been shown to interact with other death domain proteins, such as Fas (TNFRSF6)-associated via death domain (FADD) and MAP-kinase activating death domain-containing protein (MADD), and thus may function as an adaptor protein in cell death-related signaling processes. The expression of the mouse counterpart of this gene has been found to be positively regulated by the tumor suppressor p53 and to induce cell apoptosis in response to DNA damage, which suggests a role for this gene as an effector of p53-dependent apoptosis. Three alternatively spliced transcript variants encoding distinct isoforms have been reported. Besides its pro-apoptotic function it may also be involved in DNA repair as part of a protein complex formed together with the catalytic subunit of DNA-PK (DNA-PKcs) and caspase 2. Signaling pathways involving PIDD-C have been associated with the activation of NF-κB and the promotion of cell survival. Following DNA damage, PIDD-C relocates to the nucleus, where it forms a complex with RIP1 and the NF-kappa-B inhibitor kinase subunit gamma (NEMO, or IKBKG), collectively referred to as the 'NEMO-PIDDosome.' PIDD1 is also essential for translesion DNA synthesis (TLS), which enables DNA elongation across lesions in response to UV exposure.
== Treatment == While the disease is not reversible, treatments can slow further worsening. This may include the use of corticosteroids or immunosuppressive medication which may have an effect on the ability to receive a lung transplant if offered. If patients have difficulty breathing (hypoxemia) oxygen can be supplemented. Routine vaccinations are recommended for patients with chronic lung disease to prevent complications from secondary infections due to pneumonia and influenza.
Three prime untranslated regions (3′UTRs) of messenger RNAs (mRNAs) often contain regulatory sequences that post-transcriptionally influence gene expression. Such 3′-UTRs often contain both binding sites for microRNAs (miRNAs) as well as for regulatory proteins. By binding to specific sites within the 3′-UTR, miRNAs can decrease gene expression of various mRNAs by either inhibiting translation or directly causing degradation of the transcript. The 3′-UTR also may have silencer regions that bind repressor proteins that inhibit the expression of a mRNA. The 3′-UTR often contains microRNA response elements (MREs). MREs are sequences to which miRNAs bind. These are prevalent motifs within 3′-UTRs. Among all regulatory motifs within the 3′-UTRs (e.g. including silencer regions), MREs make up about half of the motifs. As of 2014, the miRBase web site, an archive of miRNA sequences and annotations, listed 28,645 entries in 233 biologic species. Of these, 1,881 miRNAs were in annotated human miRNA loci. miRNAs were predicted to have an average of about four hundred target mRNAs (affecting expression of several hundred genes). Friedman et al. estimate that >45,000 miRNA target sites within human mRNA 3′UTRs are conserved above background levels, and >60% of human protein-coding genes have been under selective pressure to maintain pairing to miRNAs. Direct experiments show that a single miRNA can reduce the stability of hundreds of unique mRNAs.
Sources: en.wikipedia.org
In contrast, each Theater Command is intended to function as a unified entity with joint operations across different military branches. The PLA on 1 August 2017 marked its 90th anniversary. Before the big anniversary it mounted its biggest parade yet and the first outside of Beijing, held in the Zhurihe Training Base in the Northern Theater Command (within the Inner Mongolia Autonomous Region). In December 2023, Reuters reported a military leadership purge after high-ranking generals were ousted from the National People's Congress. Prior to 2017, over sixty generals were investigated and sacked.
== Human proteins containing this domain == EEF1E1; EEF1G; GDAP1; GSTA1; GSTA2; GSTA3; GSTA4; GSTA5; GSTM1; GSTM2; GSTM3; GSTM4; GSTM5; GSTO1; GSTP1; GSTT1; GSTT2; GSTZ1; MARS; HPGDS; PTGDS2; PTGES2; VARS;
Chemotherapy, American Cancer Society Hazardous Drug Exposures in Health Care, National Institute for Occupational Safety and Health NIOSH List of Antineoplastic and Other Hazardous Drugs in Healthcare Settings, 2016, National Institute for Occupational Safety and Health International Ototoxicity Management Group (IOMG) - Wikiversity
Sources: en.wikipedia.org
Anti-doping laboratories typically use LC-MS/MS to detect GW501516 and its metabolites in urine. The method is sensitive and can identify the compound at low concentrations. Detection depends on sample timing, metabolism, and the specific assay.
Legality varies by country and context. It lacks marketing approval as a medicine in major countries. Sports organizations prohibit its use at all times.
A certificate of analysis may report identity, purity, and testing methods for a specific batch. It does not guarantee safety or legal status. Independent verification can confirm whether the material matches the label.
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.