LC-MS/MS raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
Reviewed 2026-07-20. Anything still debated is marked as such rather than presented as settled.
Clinical development stopped after rodent studies showed tumors at multiple sites. Whether those findings predict human cancer risk remains an open question, but they led sponsors to discontinue programs. Human safety data are limited to small, short-term studies that were not designed to assess cancer risk. Reported effects in those studies included changes in blood lipids, but the evidence is insufficient for medical use. Long-term consequences of nonmedical use are not well characterized. Questions about dose, duration, and individual susceptibility remain unresolved.
Cardarine is a common name for GW501516, an investigational compound developed in the 1990s for metabolic conditions. It acts as an agonist at peroxisome proliferator-activated receptor delta, a nuclear receptor involved in lipid and energy metabolism. The compound is frequently mislabeled as a selective androgen receptor modulator, or SARM, but its molecular target is different. GW501516 reached early clinical testing before development was discontinued. It has no approved therapeutic use in any country. The name cardarine is not a formal international nonproprietary name.
Regulatory treatment varies, but cardarine is not approved as a medicine. Sports authorities list GW501516 as a prohibited substance, and it is banned at all times under the World Anti-Doping Agency code. Many countries restrict sales for human consumption, while online vendors market it as a research chemical. Such products may lack purity data, and their actual contents can differ from the label. Purchasing or possessing cardarine may carry legal consequences depending on jurisdiction. The compound is not a dietary supplement ingredient in regulated markets.
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.
Because cardarine is not an approved medicine, no pharmacopeial monograph defines its identity, purity, or storage requirements. Laboratories typically rely on in-house methods and reference standards when testing materials labeled as GW501516. Certificates of analysis may report purity and identity for a specific batch, but their scope varies and they do not guarantee safety or legal status. Independent verification can include high-performance liquid chromatography, mass spectrometry, nuclear magnetic resonance, and elemental analysis. The distinction between research chemical labeling and human use is significant because quality standards and oversight differ.
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.
| Property | Value | Notes |
|---|---|---|
| Common synonyms | GW501516; GW-1516; endurobol | GW501516 is the research code |
| Drug class | PPARδ agonist | Not a selective androgen receptor modulator |
| Molecular formula | C21H18F3NO3S2 | Established chemical formula |
| Molar mass | 453.5 g/mol | Calculated from the formula |
| Regulatory status | Prohibited in sport; not approved as medicine | Status varies by country |
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.
Safety concerns emerged from long-term animal studies. In rodents given the compound for extended periods, researchers found an increased incidence of certain cancers, including liver and bladder tumors. These findings contributed to the discontinuation of clinical development. Whether similar risks apply to short-term or low-level exposure in humans is not established, and controlled human safety data are limited. The relevance of high-dose rodent carcinogenicity findings to human use remains a subject of debate.
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.
A persistent misconception is that cardarine is a fat-burning drug or a safe alternative to anabolic steroids. No approved therapeutic product exists, and human safety data are limited. The tumor findings in rodents remain a central concern in scientific reviews. Products sold online may contain inaccurate labels, impurities, or different compounds entirely, which complicates any assessment of effects. Independent testing of such products has reported frequent mislabeling. For these reasons, discussions in the literature emphasize risks and unknowns rather than benefits.
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.
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.
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.
=== General SPPS procedure === Stepwise SPPS proceeds from the C-terminal amino acid residue of the target peptide chain covalently attached to the resin support. Each amino acid to be coupled to the N-terminus of the resin bound nascent peptide chain must be protected on its alpha amino group using protecting groups such as Boc (acid-labile) or Fmoc (base-labile), depending on the protection strategy used (see below). The general SPPS procedure is one of repeated cycles of alternate N-terminal deprotection and peptide bond-forming 'coupling' reactions. The resin is washed with organic solvent between each chemical reaction step. Reactions in SPPS are conducted as follows:
Both laser and conventional surgeries are performed to treat glaucoma. Surgery is the primary therapy for those with congenital glaucoma. Generally, these operations are a temporary solution, as there is not yet a cure for glaucoma.
== Histopathology == Although the exact cause of this condition is not known, it is an inflammatory disorder characterized by collagen degeneration, combined with a granulomatous response. It always involves the dermis diffusely, and sometimes also involves the deeper fat layer. Commonly, dermal blood vessels are thickened (Microangiopathy). It can be precipitated by local trauma, though it often occurs without any injury. As a metabolically driven skin disorder, the pathology is characterized by poor intracellular glucose utilization leading to metabolically stressed fibroblasts. Despite an increased GLUT-1 response, fibroblasts in NL fail to produce normal collagen, weakening and breaking down the skin's structure. Vascular impairments reduce oxygen and nutrient circulation, creating hypoxia and tissue breakdown.
Non-steroidal anti-inflammatory drugs (NSAIDs) to reduce inflammation Glucocorticoids to reduce inflammation Disease-modifying anti-rheumatic drugs (DMARDs) to decrease the damaging tissue and organ effects of the inflammatory autoimmune response Because immunosuppressants weaken the overall immune response, relief of symptoms must be balanced with preserving the patient's ability to combat infections, which could potentially be life-threatening. Non-traditional treatments are being researched, developed, and used, especially when traditional treatments fail. These methods aim to either block the activation of pathogenic cells in the body, or alter the pathway that suppresses these cells naturally. These treatments aim to be less toxic to the patient and have more specific targets. Such options include:
Sources: en.wikipedia.org
=== Drug interactions === Clinical drug-drug interactions with dalbavancin have not been studied, and dalbavancin does not appear to interact with cytochrome P450 substrates, inhibitors, or inducers. It was found to have an in vitro synergistic interaction with the antimicrobial oxacillin, but the clinical significance of this interaction has yet to be established.
==== Historiography ==== Liu Wenhui retains a positive reputation in Chinese historiography, including a 2022 study by Wang Haibing, which credits his governance for promoting regional economic development and maintaining national unity. One of the main accounts of Liu Wenhui's life, a 1990 biography by Peng Dixian and Shu Guofan, is in itself written by authors who had directly participated in the events surrounding his defection and contact with the Communist Party (and more generally, the communist revolution.) Peng and Shu's biography generally characterizes Liu as a progressive and patriotic reformer, overcoming his warlord past to embrace the communist cause. Here, they assert that Liu's later alignment with the communists was the natural conclusion of his political evolution, and that his conviction towards the Communist Party became genuine over time. Liu's own autobiographical account states that his initial opposition to Chiang Kai-shek and even his initial pro-communist tilt were purely out of pragmatic self-interest driven by a desire for political survival. According to Liu, he had become a committed communist over time after receiving political education from the Ya'an radio station during the Second Sino-Japanese War. Western journalist A.
=== Locating trials === Depending on the kind of participants required, sponsors of clinical trials, or contract research organizations working on their behalf, try to find sites with qualified personnel as well as access to people who could participate in the trial. Working with those sites, they may use various recruitment strategies, including patient databases, newspaper and radio advertisements, flyers, posters in places the patients might go (such as doctor's offices), and personal recruitment of trial participants by investigators. Volunteers may search directly to locate trials using a registry run by the U.S. National Institutes of Health and National Library of Medicine to identify studies that are currently recruiting participants, offering simplified navigation and real-time enrollment trial information. Software exists to enable clinicians to find trial options for a possible participant based on genomic data for people with cancer.
Sources: en.wikipedia.org
No. Cardarine is GW501516, a PPARδ agonist, while SARMs act on androgen receptors. The two classes are often grouped in informal discussions despite different mechanisms.
No. It has no approved medical indication in any country. Regulatory agencies have not cleared it for treatment or prevention of any condition.
Early clinical work stopped after rodent carcinogenicity findings. Those animal results raised concerns about long-term human risk, although direct human evidence is lacking. The human relevance of the tumors remains an open scientific question.
Anti-doping laboratories typically use LC-MS/MS to detect GW501516 and its metabolites in urine. The method is sensitive and can identify the compound at low concentrations. Detection depends on sample timing, metabolism, and the specific assay.