If you have been reading about LC-MS/MS and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Last reviewed on 2025-11-06. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Regulatory status | Prohibited in sport | Listed by WADA as a PPARδ agonist. |
| Typical detection matrix | Urine | Most common sample for anti-doping analysis. |
| Common analytical method | LC-MS/MS | Liquid chromatography-tandem mass spectrometry. |
| Common synonyms | GW501516, GSK-516, endurobol | Names found in research and fitness contexts. |
| Typical detection window | Variable | Depends on dose, route, and individual metabolism. |
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.
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.
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.
== Medical uses == Velmanase alfa is indicated for the treatment of the non-central nervous system manifestations of alpha-mannosidosis. Alpha-mannosidosis is a rare genetic lysosomal storage disorder. The symptoms of the disorder vary, but often include mild to moderate intellectual disability, hearing loss, weakened immune system, distinctive facial features (e.g., a large head, prominent forehead, and protruding jaw), skeletal abnormalities, and muscle weakness. Alpha-mannosidosis is caused by genetic changes in the MAN2B1 gene, which codes for the lysosomal alpha-mannosidase enzyme. Mutations of the MAN2B1 gene result in the lack of production of the alpha-D-mannosidase enzyme or the production of a defective, inactive form of the enzyme. Alpha-mannosidosis affects about 1 in every 500,000 people worldwide.
Isobutyryl-CoA + 6 malonyl-CoA +12 NADPH + 12H+ → Isopalmitic acid + 6 CO2 12 NADP + 5 H2O + 7 CoA The difference between (straight-chain) fatty acid synthase and branch-chain fatty acid synthase is substrate specificity of the enzyme that catalyzes the reaction of acyl-CoA to acyl-ACP.
FAPLA's Cuban allies were less optimistic: they noted that the brigades were isolated, incapable of reinforcing each other quickly, and possessed insufficient mobile anti-aircraft weapons to protect them outside their bases. The Soviets recommended a static defence, appealing directly to Angolan President José Eduardo dos Santos, while the Cubans urged a withdrawal. Caught between two conflicting recommendations, dos Santos hesitated, and the brigades were ultimately annihilated piecemeal by the advancing South African armoured columns. Amid the confusion, a number of Angolan troops managed to break out of the South African encirclement and move north to link up with Cuban units, but a total of 471 FAPLA/PLAN personnel were killed or captured. Despite achieving their objectives during Operation Askari, the South African forces had encountered unexpectedly determined resistance from PLAN and FAPLA. The SADF acknowledged 25 killed in action and 94 wounded, the highest number of casualties suffered in any single operation since Operation Savannah. FAPLA also claimed to have shot down 4 South African aircraft.
negative supercoiling The supercoiling of a double-stranded DNA molecule in the direction opposite to the turn of the double helix itself (e.g. a left-handed coiling of a helix with a right-handed turn). Contrast positive supercoiling.
Sources: en.wikipedia.org
=== Phenylbutyrate therapy === Sodium phenylacetate/benzoate or sodium phenylbutyrate has been shown to reduce BCAA in a clinical trial done February 2011. Phenylbutyrate treatment reduced the blood concentration of BCAA and their corresponding BCKA in certain groups of MSUD patients and may be a possible adjunctive treatment.
Venous thrombosis is the formation of a thrombus (blood clot) in a vein. This most commonly affects a deep vein known as deep vein thrombosis (DVT), but can also affect a superficial vein known as superficial vein thrombosis (SVT).
== Further reading == Oliver, Brian; Devitt, Catherine; Park, Grace; Razak, Alina; Liu, Sun Mei; Bergese, Sergio D. (2025). "Drugs in Development to Manage Acute Pain". Drugs. 85 (1): 11–19. doi:10.1007/s40265-024-02118-0. PMID 39560856. Broadfoot, Marla (20 August 2024). "New Painkiller Could Bring Relief to Millions—Without Addiction Risk". Scientific American. Archived from the original on 30 December 2024. Retrieved 20 July 2026.
Sources: en.wikipedia.org
== Contraindications == Use of zolpidem may impair driving skills with a resultant increased risk of road traffic accidents. This adverse effect is not unique to zolpidem but also occurs with other hypnotic drugs. Caution should be exercised by motor vehicle drivers. The U.S. Food and Drug Administration (FDA) recommends lower doses of zolpidem due to impaired function the day after taking it. Zolpidem should not be prescribed to older people, who are more sensitive to the effects of hypnotics including zolpidem, and are at an increased risk of falls and adverse cognitive effects, such as delirium and neurocognitive disorder. Animal studies have revealed evidence of incomplete ossification and increased intrauterine fetal death at doses greater than seven times the maximum recommended human dose or higher; however, teratogenicity was not observed at any dose level. There are no controlled data on human pregnancy. In one case report, zolpidem was found in cord blood at delivery. Zolpidem is recommended for use during pregnancy only when the benefits outweigh the risks.
It has been suggested that the main role of leptin is to act as a starvation signal when levels are low, to help maintain fat stores for survival during times of starvation, rather than a satiety signal to prevent overeating. Leptin levels signal when an animal has enough stored energy to spend it in pursuits besides acquiring food. This would mean that leptin resistance in obese people is a normal part of mammalian physiology and possibly, could confer a survival advantage. Leptin resistance (in combination with insulin resistance and weight gain) is seen in rats after they are given unlimited access to palatable, energy-dense foods. This effect is reversed when the animals are put back on a low-energy diet. This also may have an evolutionary advantage: allowing energy to be stored efficiently when food is plentiful would be advantageous in populations where food frequently may be scarce. A fad diet, the Rosedale diet is based on ideas about how leptin might affect weight. It is based on unsound science and marketed with unevidenced claims of health benefits.
Shortly afterwards, the US VII Corps, in full strength and spearheaded by the 2nd Armored Cavalry Regiment, launched an armored attack into Iraq early on 24 February, just to the west of Kuwait, surprising Iraqi forces. Simultaneously, the US XVIII Airborne Corps launched a sweeping "left-hook" attack across southern Iraq's largely undefended desert, led by the US 3rd Armored Cavalry Regiment and the 24th Infantry Division (Mechanized). This movement's left flank was protected by the French Division Daguet. The 101st Airborne Division conducted a combat air assault into enemy territory. The 101st Airborne Division had struck 249 km (155 mi) behind enemy lines. It was the deepest air assault operation in history. Approximately 400 helicopters transported 2,000 soldiers into Iraq where they destroyed Iraqi columns trying to flee westward and prevented the escape of Iraqi forces. The 101st Airborne Division travelled a further 80 to 100 km (50 to 60 mi) into Iraq. By nightfall, the 101st cut off Highway 8 which was a vital supply line running between Basra and the Iraqi forces. The 101st had lost 16 soldiers in action during the 100-hour war and captured thousands of enemy prisoners of war. The French force quickly overcame Iraq's 45th Infantry Division, suffering light casualties and taking a large number of prisoners, and took up blocking positions to prevent an Iraqi counterattack on the coalition's flank. The movement's right flank was protected by the United Kingdom's 1st Armoured Division.
Sources: en.wikipedia.org
Yes, WADA prohibits cardarine as a PPARδ agonist. It appears on the prohibited list and can be detected in urine or blood. Athletes using it risk sanctions.
Detection usually uses liquid chromatography-tandem mass spectrometry after sample cleanup. Laboratories look for the parent compound or metabolites. The method requires validated reference standards and controls.
Legality varies by country. In many places it is an unapproved drug and cannot be legally sold for human consumption. Purchasing from online vendors carries legal and quality risks.
LC-MS/MS is common, often after sample cleanup. The assay targets GW501516 or its metabolites.