This is a working overview of GW501516, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2026-03-14 and is reviewed periodically as new material appears.
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.
GW501516 acts as an agonist at the peroxisome proliferator-activated receptor delta, a nuclear receptor that regulates gene expression. Activation shifts transcription toward genes involved in fatty acid uptake, oxidation, and energy expenditure. The compound does not bind the androgen receptor and therefore differs from anabolic steroids and SARMs. In rodent models, this metabolic shift has been linked to increased running endurance and reduced fat accumulation. The exact downstream pathways in humans remain incompletely characterized.
Early clinical research explored GW501516 for lipid disorders, obesity, and diabetes. Some short-term human studies reported changes in HDL cholesterol, LDL cholesterol, and triglycerides. The development program was discontinued after rodent studies showed dose-dependent tumor formation in multiple tissues, including liver, bladder, stomach, and skin. These findings raised concerns about long-term cancer risk in humans. Because human exposure data are limited, the clinical significance of the rodent tumors remains uncertain.
Literature on cardarine often separates receptor pharmacology from toxicology. Mechanistic papers describe PPARδ activation and gene expression changes, while safety assessments focus on carcinogenicity and species differences. Questions remain about whether rodent tumors arise through PPARδ-dependent or off-target mechanisms. Another open area is how human metabolism and exposure compare with those in animal studies. Analytical methods such as liquid chromatography–mass spectrometry are used to confirm identity in biological and product samples.
| 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 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.
Cardarine is a common name for GW501516, a synthetic compound studied for its effects on lipid and glucose metabolism. It functions as an agonist at peroxisome proliferator-activated receptor delta, or PPARδ, a nuclear receptor that influences gene expression. The molecule is not a steroid, nor is it a selective androgen receptor modulator. It is also known in research and sports literature as GW-501516 and endurobol. Early laboratory work examined its metabolic activity in cell cultures and animal models.
Activation of PPARδ changes transcription of genes involved in fatty acid transport, mitochondrial function, and skeletal muscle fuel preference. In rodent studies, pharmacological PPARδ activation was associated with increased endurance and altered body composition. These findings generated interest in performance enhancement, but species differences and study designs limit direct extrapolation to humans. Small human trials were conducted in the 2000s and later discontinued. The extent to which cardarine produces similar metabolic or performance effects in people remains an open question.
The compound is typically described as a laboratory compound rather than a therapeutic product. Published reports have explored its role in lipid disorders, insulin sensitivity, and exercise metabolism, yet no major drug regulator has approved it for medical use. Commercial samples sold under the cardarine name may vary in purity and identity. Analytical confirmation is therefore necessary when the material is discussed in scientific or regulatory contexts. Its classification as a prohibited substance in sport further shapes how it is studied and reported.
=== Polymorphism and temporary market withdrawal === Ritonavir was originally dispensed as a capsule that did not require refrigeration. This contained a crystal form of ritonavir that is now called form I. However, like many drugs, crystalline ritonavir can exhibit polymorphism, i.e., the same molecule can crystallize into more than one crystal type, or polymorph, each of which contains the same repeating molecule but in different crystal packings/arrangements. The solubility and hence the bioavailability can vary in the different arrangements, and this was observed for forms I and II of ritonavir. During development—ritonavir was introduced in 1996—only the crystal form now called form I was found; however, in 1998, a lower free energy, more stable polymorph, form II, was discovered. This more stable crystal form was less soluble, which resulted in significantly lower bioavailability. The compromised oral bioavailability of the drug led to temporary removal of the oral capsule formulation from the market. As a consequence of the fact that even a trace amount of form II can result in the conversion of the more bioavailable form I into form II, the presence of form II threatened the ruin of existing supplies of the oral capsule formulation of ritonavir; and indeed, form II was found in production lines, effectively halting ritonavir production. Abbott withdrew the capsules from the market, and prescribing physicians were encouraged to switch to a Norvir suspension.
== Energy release == The Q value is defined as the total energy released in a given nuclear decay. In beta decay, Q is therefore also the sum of the kinetic energies of the emitted beta particle, neutrino, and recoiling nucleus. (Because of the large mass of the nucleus compared to that of the beta particle and neutrino, the kinetic energy of the recoiling nucleus can generally be neglected.) Beta particles can therefore be emitted with any kinetic energy ranging from 0 to Q. A typical Q is around 1 MeV, but can range from a few keV to a few tens of MeV. Since the rest mass of the electron is 511 keV, the most energetic beta particles are ultrarelativistic, with speeds very close to the speed of light. In the case of 187Re, the maximum speed of the beta particle is only 9.8% of the speed of light. The following table gives some examples:
== Etymology == The U.S. government referred to the atoll as "Eniwetok" until 1974, when it changed its official spelling to "Enewetak" (along with many other Marshall Islands place names, to more properly reflect their pronunciation by the Marshall Islanders).
Sources: en.wikipedia.org
Nickel-48, discovered in 1999, is the most neutron-poor nickel isotope known. With 28 protons and 20 neutrons 48Ni is "doubly magic" (like 208Pb) and therefore much more stable, with a half-life around 3 milliseconds, than would be expected from its position in the chart of nuclides. It has the highest ratio of protons to neutrons (proton excess) of any known doubly magic nuclide.
Glargine and detemir are significantly more expensive than NPH, lente and ultralente, and they cannot be mixed with other forms of insulin. A short-acting insulin is used to simulate the endogenous insulin surge produced in anticipation of eating. Regular insulin, lispro, aspart and glulisine can be used for this purpose. Regular insulin should be given with about a 30-minute lead-time prior to the meal to be maximally effective and to minimize the possibility of hypoglycemia. Lispro, aspart and glulisine are approved for dosage with the first bite of the meal, and may even be effective if given after completing the meal. The short-acting insulin is also used to correct hyperglycemia.
OSCE Chairman Alexander Stubb said that he couldn't "make the judgment on who started the war, or how it actually started," and that the OSCE's instruments "are very limited — eight unarmed military observers, compared to the intelligence services of the rest of the world." Journalists were informed by OSCE Deputy Spokeswoman Virginie Coulloudon on "patrol reports" being made "on a daily basis", but Coulloudon also said that "the OSCE is not in a capacity to say who started the war and what happened before the night of [August] 7-8." Journalists documented multiple eyewitnesses' accounts that confirmed the reports that separatist shelling of the Georgian villages in South Ossetia took place before August 7. On 5 August 2008, the tripartite monitoring group, which included Organization for Security and Cooperation in Europe (OSCE) observers and representatives of Russian peacekeepers, issued a report that confirmed attacks against ethnic Georgian villages. The report also stated a 1992 ceasefire agreement was breached by the use of heavy artillery against the Georgian villages located in South Ossetia. The Wall Street Journal (WSJ) wrote that in an interview Grist admitted to crossing through Russian lines without authorization on his own initiative to determine the facts. Due to this fact, he was forced to resign from the OSCE immediately after the war.
== History == Frederick William Hope coined the term myiasis in 1840 to refer to diseases resulting from dipterous larvae as opposed to those caused by other insect larvae (the term for this was scholechiasis). Hope described several cases of myiasis from Jamaica caused by unknown larvae, one of which resulted in death. Even though the term myiasis was first used in 1840, such conditions have been known since ancient times. Ambroise Paré, the chief surgeon to King Charles IX and King Henry III, observed that maggots often infested open wounds.
Sources: en.wikipedia.org
=== Physical === Physical deterioration of waterlogged wood can happen immediately through the evaporation of the water. If this happens rapidly, the cells in the wood can shrink and collapse. This damage might be inevitable depending on accessibility to treatment. Additionally waterlogged wood should never be handled extensively or put on exhibit for long periods of time. Most waterlogged wood is such that decayed wood cells in the material fill with water. Depending on the wood type and how long the wood has been in water, removal of the water from the cells too rapidly (in the form of natural drying or other) could apply major stress to the cell walls and cause them to collapse. Improperly dried waterlogged irreversibly shrinks, warps, cracks and there is risk of loss to the original surface.
In experiments on Wlds mutated mice, macrophage infiltration was considerably delayed by up to six to eight days. However, once the axonal degradation has begun, degeneration takes its normal course, and, respective of the nervous system, degradation follows at the above-described rates. Possible effects of this late onset are weaker regenerative abilities in the mice. Studies indicate that regeneration may be impaired in WldS mice, but this is likely a result of the environment being unfavorable for regeneration due to the continued existence of the undegenerated distal fiber, whereas normally debris is cleared, making way for new growth.
zygosity The degree to which multiple copies of a gene, chromosome, or genome have the same genetic sequence; e.g. in a diploid organism with two complete copies of its genome (one maternal and one paternal), the degree of similarity of the alleles present in each copy. Individuals carrying two different alleles for a particular gene are said to be heterozygous for that gene; individuals carrying two identical alleles are said to be homozygous for that gene. Zygosity may also be considered collectively for a group of genes, or for the entire set of genes and genetic loci comprising the genome.
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.
It targets PPARδ, a nuclear receptor involved in lipid and energy metabolism. It does not act primarily on androgen receptors. This distinction separates it from SARMs.