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 2026-06-12. Where a claim depends on a specific study, the study is described rather than over-claimed.
Cardarine has no approved therapeutic indication and is not marketed as a medicine. The World Anti-Doping Agency lists GW501516 as a prohibited substance at all times, covering both in-competition and out-of-competition periods. National laws vary: some countries treat it as an unapproved drug subject to import controls, while others have specific restrictions on sale for human consumption. It is often sold as a research chemical, a label that does not imply safety or legality. Enforcement actions have targeted online vendors and shipments.
Anti-doping laboratories identify GW501516 and related metabolites using liquid chromatography coupled with tandem mass spectrometry. Urine is the most common matrix, though blood and dried blood spots may also be analyzed. The method targets the parent compound and phase I and phase II metabolites, which extend the detection window. Because the substance is prohibited at all times, athletes can be tested outside competition. Detection limits and windows depend on the assay, sample type, and individual metabolism.
Cardarine is frequently described as a fat-burning or endurance-enhancing supplement, but these claims exceed the available evidence. The compound is not a hormone, steroid, or selective androgen receptor modulator. Research articles discuss it as a tool compound for studying PPARδ biology, while anti-doping literature focuses on its abuse and detection. Quality of unapproved products is uncertain, and independent analyses have found impurities or incorrect labeling. Open questions include whether human cancer risk resembles that seen in rodents and how often non-athletes use the substance.
Cardarine is a common name for the investigational chemical GW501516, also written GW-1516. It was developed as a peroxisome proliferator-activated receptor delta agonist for metabolic conditions such as dyslipidemia. Early research focused on lipid handling and energy use in skeletal muscle and other tissues. The compound was never approved as a medicine. In public discussion, it is often grouped with performance-enhancing substances, although its receptor target differs from that of anabolic steroids or selective androgen receptor modulators. Regulatory and health authorities have issued warnings about its use.
GW501516 acts on PPARδ, a nuclear receptor that helps regulate fatty acid oxidation and energy homeostasis. In animal studies, activation of this receptor was associated with increased endurance and changes in lipid metabolism. Human trials examined effects on blood lipids and other metabolic markers, but the compound did not advance to approval. Rodent studies later reported tumors in multiple tissues at doses used in those experiments. Whether those findings translate to human risk remains uncertain, and the clinical relevance of the animal data is still debated.
| Property | Value | Notes |
|---|---|---|
| Regulatory status | Prohibited in sport; not approved as medicine | Listed by WADA at all times. |
| Common synonyms | GW501516, GW-501516, endurobol | Cardarine is a colloquial name. |
| Typical analytical method | LC-MS/MS | Detects parent compound and metabolites. |
| Common test matrix | Urine | Blood and dried blood spots also possible. |
| Legal classification | Varies by country | Often treated as unapproved drug or research chemical. |
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.
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.
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.
Anti-doping laboratories detect GW501516 and its metabolites using liquid chromatography-tandem mass spectrometry. Urine is the most common matrix, though blood and dried blood spots may also be used in some programs. Detection depends on factors such as dose, timing, metabolism, and the sensitivity of the assay. Published methods describe limits of detection in the low nanogram per milliliter range for related compounds. Exact detection windows are not fixed for all situations and remain an area of ongoing study.
=== Potential as a chemical weapon === The toxicity of carfentanil in humans and its ready commercial availability has raised concerns over its potential use as a chemical weapon of mass destruction by rogue nations and terrorist groups. The toxicity of carfentanil has been compared to that of nerve gas.
== Medical uses == Andexanet alfa is used to stop life-threatening or uncontrollable bleeding in people who are taking rivaroxaban or apixaban. Studies in healthy volunteers show that the molecule binds factor Xa inhibitors and counters their anti-Xa-activity. The first published clinical trial was a prospective, open label, single group study. This study reports results on 352 people and demonstrates a reduction of anti-Xa-activity while also showing an excellent or good hemostatic efficacy in 82%. While people who were expected to die in 30 days were excluded from the study, 14% of participants died. There was no relationship between hemostatic efficacy and reduced anti-Xa-activity. The FDA demanded a randomised clinical trial which resulted in publication in 2024. The ANNEXA-I trial included 530 patients with intracerebral hemorrhage who were receiving factor Xa inhibitors. Andexanet resulted in better control of hematoma expansion than usual care, but was associated with thrombotic events, including ischemic stroke. ANNEXA-I did not have sufficient power or information to draw conclusions about the effect of andexanet on mortality, clinical deterioration, or the need for rescue therapy.
It resembles Grisons Buendnerfleisch, and first appears in works on gastronomy from about 1560. Bündnerfleisch – an air-dried meat that is produced in the canton of Graubünden, Switzerland, The main ingredient is beef, taken from the animal's upper thigh or shoulder, the fat and the sinews being removed. Before drying, the meat is treated with white wine and seasonings such as salt, onion and assorted herbs.
Sources: en.wikipedia.org
Starch is stored in granule form. Starch granules are composed of a crystalline structure of amylopectin and amylose. Amylopectin forms the structure of the starch granule, with branching and non branching A-chains, B-chains, and C-chains. Amylose fills in the gaps of the amylopectin structure. Under a microscope, starch granules look like concentric layers, referred to as “growth rings”. Starch granules also contain granule-bound starch synthase and amylopectin synthesizing enzymes. Notably, starch granules vary in size and morphology across plant tissues and species.
Strychnine (, STRIK-neen, -nin, US chiefly -nyne) is a highly toxic, colorless, bitter, crystalline alkaloid used as a pesticide, particularly for killing small vertebrates such as birds and rodents. Strychnine, when inhaled, swallowed, or absorbed through the eyes or mouth, causes poisoning which results in muscular convulsions and eventually death through asphyxia. While it is no longer used medicinally, it was used historically in small doses to strengthen muscle contractions, such as a heart and bowel stimulant and performance-enhancing drug. The most common source is from the seeds of the Strychnos nux-vomica tree.
== ABC News report == An 11-segment series of reports in March 2012 from ABC News brought widespread public attention to and raised consumer concerns about the product. The product was described as "essentially scrap meat pieces compressed together and treated with an antibacterial agent". Lean finely textured beef (LFTB) was referred to as "an unappetizing example of industrialized food production". The product has been characterized as "unappetizing, but perhaps not more so than other things that are routinely part of hamburger" by Sarah Klein, an attorney for the food safety program at the Center for Science in the Public Interest. Nutritionist Andy Bellatti has referred to the product as "one of many symptoms of a broken food system". Food policy writer Tom Laskawy noted that ammonium hydroxide is only one of several chemicals routinely added to industrially produced meat in the United States. It was reported at that time that 70% of ground beef sold in US supermarkets contained the additive, and that the USDA considered it as meat. The USDA issued a statement that LFTB was safe and had been included in consumer products for some time, and its Under Secretary of Agriculture for Food Safety Elisabeth A. Hagen stated that "The process used to produce LFTB is safe and has been used for a very long time. And adding LFTB to ground beef does not make that ground beef any less safe to consume".
Sources: en.wikipedia.org
Penalties for violations of Stark Law include: denial of payment for the DHS provided; refund of monies received by physicians and facilities for amounts collected; payment of civil penalties of up to $15,000 for each service that a person "knows or should know" was provided in violation of the law, and three times the amount of improper payment the entity received from the Medicare program; exclusion from the Medicare program and/or state healthcare programs including Medicaid; and payment of civil penalties for attempting to circumvent the law of up to $100,000 for each circumvention scheme.
== Pharmacology == SSRIs are well absorbed in the gastrointestinal tract and reach peak plasma levels within 1–8 hours. During absorption SSRIs bind to proteins and are widely distributed throughout the body, including the brain, whereas they are lipophilic. Metabolism and elimination takes place mainly in the liver and most of the SSRIs produce pharmacologically active metabolites, as demonstrated in table 3 among with other pharmacology properties of the SSRIs. Table 3 Comparative pharmacology of SSRIs
=== Muscle spasticity === Tizanidine is approved and used as a muscle relaxant to treat muscle spasticity. It has been found to be as effective as other muscle relaxants and is more tolerable than baclofen and diazepam. Due to its short elimination half-life and duration, tizanidine is generally taken once every 6 to 8 hours as needed, with a maximum of 3 doses per 24 hours.
=== Other websites === TikTok is now the dominant social media platform amongst the newer generation. The popularity of TikTok has led various other web services to adopt similar features in order to compete with TikTok. Instagram launched a short, vertical videos section called Instagram Reels to its app in 2020. YouTube followed with the release of YouTube Shorts in 2021. In 2022, Facebook launched a videos tab on its app that shows users a personalized selection of videos. The same year, Twitter announced that it would also be launching a short videos feature and Amazon added a scrolling feed with photos and videos of available products to its mobile app. In 2023, Spotify redesigned its home screen to have a similar scrolling interface to TikTok and Reddit also added a separate video feed to its mobile app.
Sources: en.wikipedia.org
Legal status varies by country. It is not approved as a medicine, and it is prohibited in sport. Some jurisdictions restrict import, sale, or possession.
Laboratories use liquid chromatography-tandem mass spectrometry to detect GW501516 and its metabolites. Urine is commonly tested, and testing can occur in and out of competition.
No, cardarine is not a SARM. It is a PPARδ agonist, which acts on a different receptor. The two classes are often confused in online discussions.
No. Cardarine is a PPARδ agonist, while selective androgen receptor modulators act on androgen receptors. The two classes differ in receptor target and downstream effects.