PPARδ is one of those subjects where the details matter more than the headlines. This page pulls together the background, the mechanisms, and the practical points readers ask about most.
Last reviewed on 2026-02-04. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Appearance | White to off-white powder | Visual description for typical solid reference material. |
| Solubility | Poorly soluble in water; soluble in DMSO | Solubility depends on solvent, purity, and form. |
| Storage | Cool, dry, protected from light | Long-term storage often uses low temperature and desiccant. |
| Common analytical method | LC-MS/MS | Used for detection and quantification in biological matrices. |
| Common synonyms | GW-501516; GW501516; endurobol | Naming varies among literature, vendors, and databases. |
Protein inhibition by inhibitor binding may induce obstruction in pathway regulation, homeostatic regulation and physiological function. Competitive inhibitors compete with substrate to bind to free enzymes at active sites and thus impede the production of the enzyme-substrate complex upon binding. For example, carbon monoxide poisoning is caused by the competitive binding of carbon monoxide as opposed to oxygen in hemoglobin. Uncompetitive inhibitors, alternatively, bind concurrently with substrate at active sites. Upon binding to an enzyme substrate (ES) complex, an enzyme substrate inhibitor (ESI) complex is formed. Similar to competitive inhibitors, the rate at product formation is decreased also. Lastly, mixed inhibitors are able to bind to both the free enzyme and the enzyme-substrate complex. However, in contrast to competitive and uncompetitive inhibitors, mixed inhibitors bind to the allosteric site. Allosteric binding induces conformational changes that may increase the protein's affinity for substrate. This phenomenon is called positive modulation. Conversely, allosteric binding that decreases the protein's affinity for substrate is negative modulation.
Desiccation (drought) stress is defined as conditions where water becomes the growth limiting factor. MAAs have been reportedly found in high concentrations in many microorganisms exposed to drought stress. Particularly cyanobacteria species that are exposed to desiccation, UV radiation and oxidation stress have been shown to possess MAA's in an extracellular matrix. However it has been shown that MAAs do not provide sufficient protection against high doses of UV radiation. Thermal (heat) stress is defined as temperatures lethal or inhibitory towards growth. MAA concentrations have been shown to be up-regulated when an organism is under thermal stress. Multipurpose MAAs could also be compatible solutes under freezing conditions, because a high incidence of MAA producing organisms have been reported in cold aquatic environments.
Motilin was discovered by J.C. Brown when he introduced alkaline solution into duodena of dogs, which caused strong gastric contractions. Brown et al. predicted that alkali could either release stimulus to activate motor activity or prevent the secretion of inhibitory hormone. They isolated a polypeptide as a by-product from purification of secretin on carboxymethyl cellulose. They named this polypeptide "Motilin."
In cancer cells, an increase in Akt signaling correlates with an increase in glucose metabolism, compared to normal cells. Cancer cells favour glycolysis for energy production over mitochondrial oxidative phosphorylation, even when oxygen supply is not limited. This is known as the Warburg effect, or aerobic glycolysis. Akt affects glucose metabolism by increasing translocation of glucose transporters GLUT1 and GLUT4 to the plasma membrane, increasing hexokinase expression and phosphorylating GSK3 which stimulates glycogen synthesis. It also activates glycolysis enzymes indirectly, via HIF transcription factors and phosphorylation of phosphofructokinase-2 (PFK2) which activates phosphofructokinase-1 (PFK1). Protein kinase B PI3K/AKT/mTOR pathway Signal transduction KEGG Pathway: PI3K-Akt signaling pathway CST: PI3K/Akt Signaling Resources
Sources: en.wikipedia.org
3-Dehydrocarnitine has a role as a human metabolite, as it is an intermediate of the degradation of carnitine. Carnitine is utilized in the transport of fatty acids from the cytosol into the mitochondria of living cells during the breakdown of fatty acids for the generation of metabolic energy. In humans, 3-dehydrocarnitine is found in the blood, saliva, urine, and feces. In patients with colorectal cancer, elevated levels of 3-dehydrocarnitine have been detected, possibly due to the elevated rate of metabolism seen in malignant cancer cells. 3-Dehydrocarnitine is also found exogenously in multiple sources of food, such as poultry, lagomorph, sheep, goat, beef, venison, equine, and pork. This indicates its presence in the animals the food is derived from. 3-Dehydrocarnitine is also present in mice and Apis cerana. It is found as a metabolite in aging mouse brains, and is found as a product of Apis cerana.
The vaginal environment is slightly acidic, with pH ranging from 3.8 - 4.5 based on multiple factors such as age, natural bacteria, and stage of menstrual cycle. Due to the variety in possible pH values, this poses an interesting consideration for drug delivery. Absorption and release of drugs is often influenced by pH, so if the pH is changing through the menstrual cycle, different combinations could be needed at different times to achieve the most effective drug delivery system.
To enhance sensitivity, the secondary capillary of the nano-DESI probe can be equipped with a nebulizer, which takes benefit of the Venturi effect, facilitating the aspiration of the liquid. This enables the secondary probe to be longer, while still maintaining stable electrospray, thereby simplifying the setup process. Moreover, it offers greater versatility in nano-DESI solvent selection, allowing water to be used as an extraction solvent. This expands the technique’s chemical coverage and enhances the customization of solvent components for selective extraction of polar compounds. Additionally, the capillaries can be integrated into a custom 3D-printed cassette, creating a convenient plug-and-play device.
The tine test, which uses a "button" with four to six short needles coated with tuberculin instead of an injection. It is easier to administer. It has comparable results if "doubtful" indications are treated as positive. The US CDC and the American Thoracic Society believe that it is less reliable because the amount of tuberculin that enters the skin cannot be accurately determined, despite the aforementioned results. The Heaf test, a test similar to the tine test formerly used in the United Kingdom. A spring-loaded instrument with six needles is used. It stopped being used in 2005 as the manufacturer deemed the production of this instrument financially unsustainable.
The American Society of Plant Biologists (ASPB) is a non-profit professional society for research and education in plant science. It was founded in 1924 as the American Society of Plant Physiologists (ASPP); the name was changed in 2001. Membership in the society is open to any person from any country who deals with physiology, molecular biology, environmental biology, cell biology and plant biophysics or related issues. It has over 4,000 members worldwide. The society publishes the peer-reviewed journals Plant Physiology (1926–) and The Plant Cell (1989–) as well as ASPB News. The American Society of Plant Biologists also has partnered with the Society for Experimental Biology, and John Wiley & Sons to publish an online-only science journal Plant Direct. In 2000, it published the first edition of the textbook Biochemistry & Molecular Biology of Plants. The first President of the Society was Charles Albert Shull (1924–1925), with founder R. B. Harvey as Secretary-Treasurer. Other presidents of the Society include Harry Beevers (1961–1962), Aubrey Naylor (1960–1961), and Katayoon Dehesh (2021-2022). The first woman to be president of the society was Elisabeth Gantt (1988–1989).
Sources: en.wikipedia.org
Cardarine targets PPARδ, a nuclear receptor involved in lipid and energy metabolism. It does not bind the androgen receptor in the way SARMs do.
Most methods use liquid chromatography with tandem mass spectrometry. Urine is common in anti-doping testing, and blood or plasma may be used in research.
Typical guidance is cool, dry, dark storage, often at low temperature and with desiccant. Stability data are limited, so storage conditions should be verified for each batch or supplier.
Cardarine is an investigational synthetic compound that acts as a PPARδ agonist. It is also known as GW501516 and has been studied mainly in preclinical research. It is not an approved medicine.