Everything below concerns clinical development. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Updated 2026-03-07. Numbers and descriptions here follow the published literature rather than marketing material.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Appearance | White to off-white powder | Common for reference-grade material. |
| Solubility | Low in water | Dissolves in DMSO and some organic solvents. |
| Typical storage | -20 °C, desiccated | Protect from light and moisture. |
| Analytical method | LC-MS/MS | Used for trace detection in biological matrices. |
| Purity assessment | HPLC with UV detection | Often combined with NMR and mass spectrometry. |
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.
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.
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.
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.
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.
=== Naming conventions === The first part of an intein name is based on the scientific name of the organism in which it is found, and the second part is based on the name of the corresponding gene or extein. For example, the intein found in Thermoplasma acidophilum and associated with vacuolar ATPase subunit A (VMA) is called "Tac VMA". Normally, as in this example, just three letters suffice to specify the organism, but there are variations. For example, additional letters may be added to indicate a strain. If more than one intein is encoded in the corresponding gene, the inteins are given a numerical suffix starting from 5′ to 3′ or in order of their identification (for example, "Msm dnaB-1"). The segment of the gene that encodes the intein is usually given the same name as the intein, but to avoid confusion the name of the intein proper is usually capitalized (e.g., Pfu RIR1-1), whereas the name of the corresponding gene segment is italicized (e.g., Pfu rir1-1). A different disambiguating convention is to place a lowercase "i" after the source protein name, e.g. "Msm DnaBi1".
=== Analytical methods === Several relatively simple chemical tests—commercially available as reagent testing kits—can be used to assess the presence of psilocybin in extracts prepared from mushrooms. The drug produces a yellow color in the Marquis test and a green color in the Mandelin reagent. Neither of these tests is specific for psilocybin; for example, the Marquis test will react with many classes of controlled drugs, such as those containing primary amino groups and unsubstituted benzene rings, including amphetamine and methamphetamine. Ehrlich's reagent and DMACA reagent are used as chemical sprays to detect the drug after thin layer chromatography. Many modern techniques of analytical chemistry have been used to quantify psilocybin levels in mushroom samples. Although the earliest methods commonly used gas chromatography, the high temperature required to vaporize the psilocybin sample before analysis causes it to spontaneously lose its phosphoryl group and become psilocin, making it difficult to chemically discriminate between the two drugs. In forensic toxicology, techniques involving gas chromatography coupled to mass spectrometry (GC–MS) are the most widely used due to their high sensitivity and ability to separate compounds in complex biological mixtures. These techniques include ion mobility spectrometry, capillary zone electrophoresis, ultraviolet spectroscopy, and infrared spectroscopy. High-performance liquid chromatography (HPLC) is used with ultraviolet, fluorescence, electrochemical, and electrospray mass spectrometric detection methods.
== Potential health risks == The potential health impacts of MNPs vary based on factors such as particle size, shape, exposure time, chemical composition (e.g. enriched with heavy metals, polycyclic aromatic hydrocarbons, etc.), surface properties, and associated contaminants. Experimental and observational studies in mammals have reported a range of biological responses to micro and nanoplastic exposure. It is shown that MPs and NPs exposure have the following adverse effects:
Sources: en.wikipedia.org
=== Physical measures === There is not enough evidence to determine the effectiveness of massage therapy. The evidence for manual therapy is inconclusive. A 2015 review indicated that aquatic therapy is safe, effective, and can be an adjunct therapy for knee osteoarthritis. Among people with hip and knee osteoarthritis, water exercise may reduce pain and disability, and increase quality of life in the short term. Hydrotherapy might also be an advantage in the management of pain, disability, and quality of life. Functional, gait, and balance training have been recommended to address impairments of position sense, balance, and strength in individuals with lower extremity arthritis, as these can contribute to a higher rate of falls in older individuals. For people with hand osteoarthritis, exercises may provide small benefits for improving hand function, reducing pain, and relieving finger joint stiffness. A study showed that there is low-quality evidence that weak knee extensor muscles increase the risk of knee osteoarthritis. Strengthening of the knee extensors could prevent knee osteoarthritis. Lateral wedge insoles and neutral insoles do not appear to be useful in osteoarthritis of the knee. Knee braces may help, but their usefulness has also been disputed.
When bound in the active site of an oxidoreductase, the nicotinamide ring of the coenzyme is positioned so that it can accept a hydride from the other substrate. Depending on the enzyme, the hydride donor is positioned either "above" or "below" the plane of the planar C4 carbon, as defined in the figure. Class A oxidoreductases transfer the atom from above; class B enzymes transfer it from below. Since the C4 carbon that accepts the hydrogen is prochiral, this can be exploited in enzyme kinetics to give information about the enzyme's mechanism. This is done by mixing an enzyme with a substrate that has deuterium atoms substituted for the hydrogens, so the enzyme will reduce NAD+ by transferring deuterium rather than hydrogen. In this case, an enzyme can produce one of two stereoisomers of NADH. Despite the similarity in how proteins bind the two coenzymes, enzymes almost always show a high level of specificity for either NAD+ or NADP+. This specificity reflects the distinct metabolic roles of the respective coenzymes, and is the result of distinct sets of amino acid residues in the two types of coenzyme-binding pocket. For instance, in the active site of NADP-dependent enzymes, an ionic bond is formed between a basic amino acid side-chain and the acidic phosphate group of NADP+. On the converse, in NAD-dependent enzymes the charge in this pocket is reversed, preventing NADP+ from binding.
==== Elimination ==== Modafinil is eliminated 90% via metabolism and 10% via renal excretion. Modafinil, given as a single dose in radiolabeled form, is excreted 80% in urine and 1% in feces by 11 days post-administration. Urinary recovery as the major metabolite modafinil acid has been found to be 35 to 51% of a dose. Less than 10% of modafinil is excreted unchanged in urine. The elimination half-life of modafinil is in the range of 12 to 15 hours There is individual variation in this parameter depending on sex, cytochrome P450 genotypes, liver function, and renal function. The individual enantiomers of modafinil, armodafinil and esmodafinil, have substantially different pharmacokinetics due to differing elimination profiles. Both armodafinil and esmodafinil are eliminated in a monophasic manner. However, armodafinil has a half-life of 10 to 17 hours, while esmodafinil has a half-life of 3 to 5 hours (3–4 times shorter). Consequently, modafinil has a biphasic elimination profile, with esmodafinil being eliminated much more rapidly than armodafinil. Armodafinil and modafinil have shown virtually identical elimination half-lives of approximately 12 to 16 hours in directly comparative studies. However, due to the biphasic elimination profile of modafinil, armodafinil shows higher levels than modafinil from 4 to 6 hours after administration and about 40% higher area-under-the-curve (AUC) levels than modafinil. Moreover, armodafinil showed 42% lower peak-to-trough variation than modafinil with once-daily administration at steady state.
=== 21 March === The SAF retook the Republican Palace in Khartoum from the RSF. An RSF drone strike on the palace that same day killed six journalists including two military reporters and four members of a Sudan TV crew.
Sources: en.wikipedia.org
LC-MS/MS is common, often after sample cleanup. The assay targets GW501516 or its metabolites.
Reference material is usually kept cold, dry, and protected from light. Frozen aliquots reduce repeated freeze-thaw cycles.
No approved pharmaceutical product exists, so manufacturing and quality controls are not standardized. Products may contain different compounds or impurities.
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.