If you have been reading about nuclear receptor and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Last reviewed on 2026-04-06. Where a claim depends on a specific study, the study is described rather than over-claimed.
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 is prohibited in competitive sport under the World Anti-Doping Agency code, where it is classified as a metabolic modulator. It is not approved as a prescription medicine in the United States, European Union, or other major markets. Regulatory action has focused on its presence in sports and in products marketed as research chemicals. Because it has no accepted medical indication, supply is often unregulated. This status creates legal and safety uncertainties for anyone who encounters the substance.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Regulatory status | Prohibited in sport | Listed by WADA as a metabolic modulator. |
| Approved medical use | None in major jurisdictions | Not a registered drug. |
| Common test matrix | Urine | Most anti-doping samples use urine. |
| Typical detection method | LC-MS/MS | Detects parent compound and metabolites. |
| Reference standard storage | -20 °C, desiccated | Typical for analytical standards. |
Detection of GW501516 in biological samples generally relies on liquid chromatography coupled with tandem mass spectrometry. Urine is a common matrix in anti-doping analysis, while blood or plasma may be used in research settings. Sample preparation can involve enzymatic hydrolysis, protein precipitation, or solid-phase extraction before instrumental analysis. Because the compound undergoes metabolism, assays may target the parent molecule, one or more metabolites, or both. Detection windows are not fixed; they depend on factors such as dose, route, individual metabolism, and assay sensitivity. Reference standards are required for accurate identification and quantification.
Handling and quality assessment of cardarine reference material follow general laboratory practices for poorly characterized compounds. It typically appears as a white to off-white powder and is sparingly soluble in water but soluble in organic solvents such as dimethyl sulfoxide and ethanol. Storage recommendations usually specify a cool, dry, dark place, with long-term storage at low temperature and desiccation. Purity may be checked by high-performance liquid chromatography with ultraviolet detection, while identity is confirmed by mass spectrometry and nuclear magnetic resonance. No pharmacopeial monograph exists, so reported purity and stability depend on the supplier’s methods.
GW501516 acts as a selective agonist at PPARδ, a nuclear receptor that regulates transcription of genes involved in lipid handling and energy metabolism. Activation of PPARδ in preclinical models increases fatty acid oxidation, mitochondrial biogenesis, and exercise endurance in rodents. These effects have made the compound a subject of metabolic research and also a target for sport anti-doping rules. In humans, however, controlled studies are limited, and whether similar endurance or metabolic changes occur at tolerated exposures remains an open question. The receptor’s broad tissue distribution also means downstream effects may vary by organ and condition.
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, 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.
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.
GW501516 acts as an agonist at peroxisome proliferator-activated receptor delta, a nuclear receptor involved in transcription of genes related to lipid handling and energy use. Activation of PPARδ can shift skeletal muscle toward greater fatty acid oxidation in animal models, which is one reason it drew interest for metabolic disease and exercise research. The exact downstream effects depend on tissue, species, dose, and duration. Human data are sparse, so many proposed benefits remain hypotheses rather than established clinical outcomes.
Laboratory studies have examined GW501516 in cell cultures and rodents for conditions such as dyslipidemia, insulin resistance, and obesity. Some trials in humans were initiated, but development was discontinued after preclinical findings raised concerns about cancer in certain models. Those findings do not prove that the compound causes cancer in people, but they contributed to regulatory caution. Later reviews often describe the evidence as preliminary and insufficient for assessing long-term safety.
===== Parenchyma ===== Parenchyma (Greek, para – 'beside'; enchyma– infusion – 'tissue') is the bulk of a substance. In plants, it consists of relatively unspecialized living cells with thin cell walls that are usually loosely packed so that intercellular spaces are found between cells of this tissue. These are generally isodiametric in shape. They contain small number of vacuoles or sometimes they even may not contain any vacuole. Even if they do so the vacuole is of much smaller size than of normal animal cells. This tissue provides support to plants and also stores food. Chlorenchyma is a special type of parenchyma that contains chlorophyll and performs photosynthesis. In aquatic plants, aerenchyma tissues, or large air cavities, give support to float on water by making them buoyant. Parenchyma cells called Idioblast have metabolic waste. Spindle shaped fibers are also present in this cell to support them and known as prosenchyma, succulent parenchyma also noted. In xerophytes, parenchyma tissues store water.
=== Biosynthesis === Cannabinoid production begins with an enzyme combining geranyl pyrophosphate and olivetolic acid to form CBGA. CBGA is converted to THCA, CBDA, or CBCA by separate synthases, FAD-dependent dehydrogenase enzymes that diverged from a promiscuous common ancestor. There is no enzymatic conversion of CBDA or CBD to THCA or THC. Propyl homologues (CBGVA, THCVA, CBDVA, CBCVA) follow an analogous pathway from divarinolic acid.
The United States has maintained a space program since the late 1950s, beginning with the establishment of the National Aeronautics and Space Administration (NASA) in 1958. In 1961, the United States became the second country (after the Soviet Union) to successfully launch a human into space. NASA's Apollo program (1961–1972) achieved the first crewed Moon landing with the 1969 Apollo 11 mission; it remains one of the agency's most significant milestones. Other major endeavors by NASA include the Space Shuttle program (1981–2011), the Voyager program (1972–present), the Hubble and James Webb space telescopes (launched in 1990 and 2021, respectively), and the multi-mission Mars Exploration Program (Spirit, Opportunity, Curiosity, and Perseverance). NASA is one of five agencies collaborating on the International Space Station (ISS); U.S. contributions to the ISS include several modules, including Destiny (2001), Harmony (2007), and Tranquility (2010), as well as ongoing logistical and operational support. The United States private sector dominates the global commercial spaceflight industry. Prominent American spaceflight contractors include Blue Origin, Boeing, Lockheed Martin, Northrop Grumman, and SpaceX. NASA programs such as the Commercial Crew Program, Commercial Resupply Services, Commercial Lunar Payload Services, and NextSTEP have facilitated growing private-sector involvement in American spaceflight.
These, some argue, need to be included in the assessment since health technology is never purely a matter of science but also of beliefs, values, and ideologies. One of the mechanisms being suggested either as an element of or an alternative to the current TAs is bioethics, which is also referred to as the "fourth-generation" evaluation framework. There are at least two dimensions to an ethical HTA. The first involves the incorporation of ethics in the methodological standards employed to assess technologies while the second is concerned with the use of ethical framework in research and judgment on the part of the researchers who produce information used in the industry.
Triisopropyl silane (TIPS) is an organosilicon compound with the formula (i-Pr)3SiH (i-Pr = isopropyl). This colorless liquid is used as a scavenger in peptide synthesis. It can also act as a mild reducing agent. In peptide synthesis, TIPS is used as a scavenger for peptide groups being removed from the peptide sequence at the global deprotection. TIPS is able to scavenge carbocations formed in the deprotection of a peptide as it can act as a hydride donor in acidic conditions. Silanes may be preferred as scavengers in place of sulfur-based scavengers.
Sources: en.wikipedia.org
==== In children ==== The NICE Guideline recommends that SSRIs should not be used to treat depression in children and young people, except for fluoxetine, which may be considered for moderate to severe depression when psychological therapies alone are insufficient. In the United States, they are approved for use in pediatric patients; however, individuals under 25 years of age should be closely monitored for an increased risk of suicidality, as indicated by the FDA black box warning. SSRIs have the best outcomes when combined with cognitive-behavioral therapy. Their benefits are modest and tolerability varies. The benefits may be clinically unimportant and there are uncertain effects on suicide risk.
Despite his criticisms against Marcos, Duterte clarified the prayer rallies were not meant to overthrow the administration but warned Marcos of extending his six-year term, reminding Marcos of his father's fate.
==== Effects on mental health ==== Based on a nationally representative sample of 20,847 US adults, a 2026 survey study in JAMA Network Open found that daily generative AI use was significantly associated with greater depressive symptoms, with the odds of at least moderate depression roughly 30% higher among daily users than among non-users. The association was strongest for personal use and among those aged 25 to 64; the cross-sectional design did not allow for causal conclusions. Separately, a 2025 nationally representative survey of US adolescents and young adults (aged 12 to 21) found that roughly 13% had used generative AI for emotional support, with more than 90% of them reporting the advice as helpful. Controlled trials have shown some therapeutic potential. The first randomized controlled trial of a fully generative AI therapy chatbot, published in NEJM AI in 2025, found significant reductions in symptoms of depression, anxiety, and eating disorders over four weeks compared to a waitlist control, with participants rating the therapeutic alliance as comparable to that of human therapists. These findings are consistent with a 2025 meta-analysis of 31 RCTs (n=29,637) that found small-to-moderate effects of AI chatbots in reducing depressive, anxiety, and stress symptoms among young adults.
== Mode of action == The exact activation mechanism of Ppk1/Ppk26 ion channels in the presence of Do6a is unknown; however, it likely compares to the mode of action of endogenous peptide Vulnusin due to their similarity in structure. Vulnusin binds to Ppk/Bba channels upon mechanical injury, yet administration of this peptide independently still results in channel activation and nociceptive rolling in Drosophila larvae. This could mean that a wound in larvae tissue allows Vulnusin, normally located above the epidermal layer, to reach its receptors below epidermal cells. Do6a, delivered to Ppk/Bba receptors through a mechanical puncture of the tissue from the velvet ant sting, could elicit its response through a similar mechanism. Since Ppk1/Ppk26 ion channels are homologous to Acid-sensing ion channels (ASICs) in vertebrates, they are likely to be permeable to cations, however, the exact ion type that passes through these channels upon activation has not been determined.
Sources: en.wikipedia.org
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.
Anti-doping laboratories use LC-MS/MS to detect GW501516 and its metabolites, usually in urine. The method can identify the parent compound at low concentrations. Detection windows vary with dose and individual factors.
No, cardarine has no approved medical uses in major jurisdictions. Early research explored metabolic conditions, but those programs were discontinued. It is not a registered treatment for any disease.
Cardarine is a common name for GW501516, a synthetic PPARδ agonist. It is not a steroid or a selective androgen receptor modulator. It was developed and studied as a research compound for metabolic pathways.