Metabolite 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 2025-11-14. Where a claim depends on a specific study, the study is described rather than over-claimed.
Human trials of GW501516 were small and short in duration. They examined lipid levels, glucose handling, and other metabolic markers, but the programs were halted after the animal cancer findings. No approved therapeutic product exists, and published human data are insufficient for establishing long-term safety. Reports of use for athletic performance come mainly from non-clinical settings and cannot be verified through controlled trials. Independent testing of products sold as cardarine has found inconsistent purity and labeling.
Laboratory studies indicate that GW501516 activates PPARδ, a nuclear receptor involved in fatty acid oxidation and energy metabolism. In rodent experiments, treated animals often showed increased endurance and reduced fat mass. These effects were observed under controlled conditions and do not establish safe or effective use in humans. The exact dose-response relationship in humans remains poorly characterized. Species differences in metabolism can affect how results translate across animals and people.
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 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.
| Property | Value | Notes |
|---|---|---|
| Primary target | PPARδ (NR1C2) | Nuclear receptor involved in lipid metabolism |
| Preclinical effect | Increased fatty acid oxidation | Observed in rodent studies |
| Key safety signal | Tumors in rodents after long-term exposure | Contributed to halted clinical development |
| Human trial status | No approved product; development stopped | Limited short-term metabolic data |
| Sport regulatory status | Prohibited at all times | WADA hormone and metabolic modulators class |
Cardarine is not approved for human therapeutic use in any major jurisdiction. It appears on the World Anti-Doping Agency Prohibited List as a PPARδ agonist within the hormone and metabolic modulators category. Sports organizations test for it because it has been detected in athlete samples and seized products. Regulatory actions against marketed research chemical versions have occurred in several countries, though enforcement varies. Availability through unregulated channels complicates oversight.
Analytical laboratories typically identify cardarine and its metabolites using liquid chromatography-tandem mass spectrometry. Urine is a common matrix in anti-doping testing, while blood and tissue may be used in research settings. Detection windows depend on the assay, the sample matrix, and the compound's metabolism. Because cardarine is extensively metabolized, laboratories often target specific metabolites to improve sensitivity and confirmation. Reference standards are required for reliable quantification. Method validation includes checks for selectivity, linearity, and carryover.
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.
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.
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.
Stability of GW501516 depends on form, temperature, light exposure, and moisture. Solid reference material is typically stored frozen or refrigerated in a desiccator and protected from light. Solutions in organic solvents such as dimethyl sulfoxide are often kept frozen in aliquots to reduce freeze-thaw cycling. Aqueous solubility is low, so aqueous stock solutions can be difficult to prepare without cosolvents. Degradation may appear as changes in chromatographic purity or mass spectral signal. Stability studies are needed to establish shelf life for any specific preparation.
== Lead-like == During drug discovery, lipophilicity and molecular weight are often increased in order to improve the affinity and selectivity of the drug candidate. As a result, it is often difficult to maintain drug-likeness (i.e., RO5 compliance) during hit and lead optimization. To solve this problem, it has been proposed that members of screening libraries from which hits are discovered should be biased toward lower molecular weight and lipophilicity so that medicinal chemists will have an easier time in delivering optimized drug development candidates that are also drug-like. Hence the rule of five has been extended to the rule of three (RO3) for defining lead-like compounds. A rule of three compliant compound is defined as one that has:
==== Metabolism ==== Etilefrine is metabolized by conjugation, for instance glucuronidation, in the liver and gastrointestinal tract. There appears to be significant first-pass metabolism. About 3% is metabolized into hydroxymandelic acid.
Rapid and simple – simple contact for 10–120 minutes and constructs spontaneously and stably incorporate – no washing required. Replicable – same variables (time, temperature, concentration) equals the same result. Toxicity – FSL constructs are biocompatible, disperse into biological solutions without solvents, detergents. They label non-covalently and are non-genetic. Normal vitality and functionality is maintained in modified cells/virions/organisms. Toxicity/vitality experiments in small laboratory animals, zebrafish, cell cultures, spermatozoa and embryos find no toxic effects within physiological ranges. Amphiphilic – the amphiphilic nature of the FSL Kode construct makes them water dispersible (clear solution of micelles), yet once interacted with a membrane they insert/coat and become water resistant Variable design – a single F can be presented in more than 100 ways by varying the spacer and lipid. High biovisibility – as the spacer holds the F moiety away for the membrane it is able to achieve increased sensitivity, specificity and reactivity can be optimized by use of multiple and variable biomarker presentations on the same surface. Additive – FSL modification is compatible with other technologies allowing users to add additional features to cells/viruses/organisms/surfaces already modified by more traditional methods. Multiple FSL constructs may be added to a surface simultaneously by simply creating a mix of FSL Kode constructs. Constructs insert into living or fixed cell (glutaraldehyde) membranes.
== Use and effects == A phase 1 dose-ranging clinical trial found that zalsupindole is non-hallucinogenic in humans across a dose range of 2 to 360 mg orally. Nonetheless, it produced changes in brain function as measured by quantitative electroencephalography (qEEG).
Sources: en.wikipedia.org
Despite the Conscription Law of 1873, and all the reforms and progress, the new Japanese army was still untested. That all changed in 1877, when Saigō Takamori led the last rebellion of the samurai in Kyūshū. In February 1877, Saigō left Kagoshima with a small contingent of soldiers on a journey to Tokyo. Kumamoto castle was the site of the first major engagement when garrisoned forces fired on Saigō's army as they attempted to force their way into the castle. Rather than leave an enemy behind him, Saigō laid siege to the castle. Two days later, Saigō's rebels, while attempting to block a mountain pass, encountered advanced elements of the national army en route to reinforce Kumamoto castle. After a short battle, both sides withdrew to reconstitute their forces. A few weeks later, the national army engaged Saigō's rebels in a frontal assault at what later known as the Battle of Tabaruzaka. During this eight-day-battle, Saigō's nearly ten thousand strong army battled hand-to-hand the equally matched national army. Both sides suffered nearly four thousand casualties during this engagement. Due to conscription, however, the Japanese army was able to reconstitute its forces, while Saigō's was not. Later, forces loyal to the emperor broke through rebel lines and managed to end the siege on Kumamoto Castle after fifty-four days. Saigō's troops fled north and were pursued by the national army. The national army caught up with Saigō at Mt. Enodake. Saigō's army was outnumbered seven-to-one, prompting a mass surrender of many samurai.
While certain effects of developmental temperature, like body size, are irreversible in ectotherms, others can be reversible. When Drosophila melanogaster develop at cold temperatures they will have greater cold tolerance, but if cold-reared flies are maintained at warmer temperatures their cold tolerance decreases and heat tolerance increases over time. Because insects typically only mate in a specific range of temperatures, their cold/heat tolerance is an important trait in maximizing reproductive output. While the traits described above are expected to manifest similarly across sexes, developmental temperature can also produce sex-specific effects in D. melanogaster adults.
=== The aspartate family of amino acids === The aspartate family of amino acids includes: threonine, lysine, methionine, isoleucine, and aspartate. Lysine and isoleucine are considered part of the aspartate family even though part of their carbon skeleton is derived from pyruvate. In the case of methionine, the methyl carbon is derived from serine and the sulfur group, but in most organisms, it is derived from cysteine.
Sources: en.wikipedia.org
Rodent studies reported increased endurance and fat oxidation after GW501516 exposure. Long-term studies also found higher rates of some tumors, which led to halted development.
Small short-term human trials examined metabolic markers such as lipids and glucose. The trials did not continue after rodent cancer findings, so long-term human safety is unknown.
Controlled human trials have not established a performance benefit. Anecdotal reports exist, but they are not reliable evidence.
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.