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 2026-03-09. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
A common misconception is that cardarine has been proven safe for human use. In reality, human clinical data are limited, and long-term animal studies have raised concerns about cancer. Another misconception is that it is a supplement or vitamin-like compound. It is a synthetic research chemical with no approved medical indication. Scientific discussion often focuses on its mechanism and detection rather than therapeutic use. Regulatory and anti-doping literature treats it primarily as a prohibited substance.
Cardarine is explicitly prohibited by the World Anti-Doping Agency under the class of PPARδ agonists. Its presence in urine or blood samples can be detected using mass spectrometry-based methods, often liquid chromatography-tandem mass spectrometry. Athletes who test positive may face sanctions, including bans from competition. The compound is also regulated as a prescription-only or unapproved drug in many countries. Enforcement varies by jurisdiction, and some regions treat it as a controlled substance. Online sales may occur despite these restrictions, creating quality and legal risks.
Laboratory detection of cardarine typically involves sample preparation followed by chromatographic separation and mass spectrometric identification. Urine is the most common matrix for anti-doping tests, though blood and hair have also been explored. Methods can target the parent compound or its metabolites, depending on the expected window of detection. Reference standards are required for accurate quantification. Matrix effects and dilution can influence results, so laboratories use internal standards and validation protocols. The exact detection window varies with dose, route, and individual metabolism.
| Property | Value | Notes |
|---|---|---|
| Primary target | PPARδ | Nuclear receptor; not androgen receptor |
| Studied indications | Dyslipidemia; obesity; diabetes | Early clinical research; development discontinued |
| Rodent toxicity | Tumor formation in multiple tissues | Dose-dependent findings in some studies |
| Human approval | None | No approved therapeutic use |
| Typical analytical method | LC-MS/MS | Used for identity and quantification |
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.
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.
In the fitness and bodybuilding literature, cardarine is frequently discussed as an endurance agent or fat-loss compound, although such claims are not supported by robust clinical evidence. Online descriptions often mix animal data, user anecdotes, and marketing language. Researchers who study PPARδ agonists distinguish between receptor activation in controlled experiments and unsupervised use of unverified products. The latter introduces unknown purity, dose, and interactions, making reported experiences difficult to interpret scientifically.
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.
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.
Lange Zeit ging man davon aus, Rezeptoren übermittelten Wirkungen ausschließlich in ihren funktionellen Grundformen – als Monomere. Der erste Hinweis auf die Existenz von GPCR-Oligomeren geht zurück auf das Jahr 1975. Lefkowitz und Mitarbeiter hatten an beta-Adrenozeptoren ein Verhalten beobachtet, das als negative Kooperativität bekannt ist und das auf der Existenz von Rezeptordimeren oder -oligomeren beruht. Zu Beginn der 1980er Jahre wurde die Hypothese aufgestellt, Rezeptoren könnten größere Verbände, sogenannte Mosaike, ausbilden oder zwei Rezeptoren könnten direkt miteinander interagieren. Massenbestimmungen von beta-Adrenozeptoren (1982) und Muskarinrezeptoren (1983) zeigten, dass die Rezeptoren in homodimeren oder -tetrameren Formen vorkommen können. 1991 wurden Erscheinungen beobachtet, die als Übersprechen interpretiert werden können und somit auf eine Rezeptor-Heteromer-Expression hinwiesen. Gegenstand der Untersuchung waren Adenosin A2A- und Dopamin D2-Rezeptoren. Maggio und Mitarbeiter zeigten 1993 die Fähigkeit zweier G-Protein-gekoppelter Rezeptoren zu heteromerisieren, indem sie Chimären von Muskarin-M3-Rezeptoren und α2C-Adrenozeptoren einsetzten. Im Jahr 2005 wurde der Beweis erbracht, dass Rezeptoroligomeren im lebenden Organismus funktionelle Bedeutung zukommt. Die Kristallstruktur eines CXCR4-Dimers wurde im Jahr 2010 veröffentlicht.
=== Auswirkung der Oligomerisierung === GPCR-Oligomere bestehen aus Dimeren, Trimeren, Tetrameren oder Verbänden höherer Ordnung. Die Oligomere sind als Entitäten anzusehen, die Eigenschaften aufweisen, die sich mehr oder weniger und in vielerlei Hinsicht von denen der Monomeren unterscheiden. Der funktionelle Charakter eines Rezeptors ist abhängig von seiner tertiär- bzw. quartärstrukturellen Gestalt. Berühren sich Rezeptoren auf einer größeren Fläche oder an sensiblen Stellen, dann wirken Kräfte ein, die die Gestalt wie auch die innere Beweglichkeit der nunmehrigen Protomere verändern; kurzum, Protomere wirken als allosterische Modulatoren aufeinander ein. Dies hat Konsequenzen für:
die Belieferung der Zelloberfläche mit Rezeptoren die Ligandbindung an diversen Bindungsstellen die G-Protein-Kopplung den innerzelluären Verkehr (vergleiche Signaltransduktion) die Modifizierung der Desensibilisierungsprofile die Neigung zur Endozytose und Internalisierung das postendozytotische Schicksal der Rezeptoren Es ist gegenwärtig unklar, ob alle Rezeptoroligomere eine funktionelle Bedeutung in der Signalübertragung haben.
== Literatur == R. Rozenfeld, L. A. Devi: Exploring a role for heteromerization in GPCR signalling specificity. In: Biochem J. Band 433, 2011, S. 11. PMID 21158738. N. J. Smith, G. Milligan: Allostery at G protein-coupled receptor homo- and heteromers: uncharted pharmacological landscapes. In: Pharmacological reviews. Band 62, Nummer 4, Dezember 2010, S. 701–725, doi:10.1124/pr.110.002667. PMID 21079041, PMC 2993260 (freier Volltext) (Review). J. González-Maeso: GPCR oligomers in pharmacology and signaling. In: Molecular brain. Band 4, Nummer 1, 2011, S. 20, doi:10.1186/1756-6606-4-20. PMID 21619615, PMC 3128055 (freier Volltext) (Review). J. Giraldo, J. P. Pin: G Protein-coupled Receptors: From Structure to Function. Royal Society of Chemistry, 2011, ISBN 978-1-84973-183-6. A. Gilchrist: GPCR Molecular Pharmacology and Drug Targeting: Shifting Paradigms and New Directions. John Wiley & Sons, 2010, ISBN 978-1-118-03517-7.
Sources: de.wikipedia.org
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.
Rodent studies found dose-dependent tumors in several organs. The sponsor discontinued the program over cancer concerns. Human risk from long-term use remains unknown.
Controlled human endurance trials are lacking. Animal studies show increased exercise capacity under some conditions. Anecdotal reports are not equivalent to clinical evidence.
Yes, WADA prohibits cardarine as a PPARδ agonist. It appears on the prohibited list and can be detected in urine or blood. Athletes using it risk sanctions.