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Detection, Stability, And Quality — Research Overview

By Editorial Desk · published 2026-07-20 · last reviewed 2026-08-01 · Wiki

prohibited list comes up often in conversation and rarely with the context attached. Here we lay out the basics in order, then work through the practical considerations.

Last reviewed on 2026-08-01. Where a claim depends on a specific study, the study is described rather than over-claimed.

Detection, Stability, and Quality

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.

Background and Regulatory Status

Sporting authorities added GW501516 to prohibited lists after it appeared in athlete samples and online markets. The World Anti-Doping Agency classifies it as a hormone and metabolic modulator, and its use can lead to an anti-doping rule violation. Some early laboratory work suggested effects on fatty acid oxidation and endurance-related metabolism in animals, but those findings do not establish safe or effective use in people. Reports of adverse events in humans are scarce and often anecdotal, which complicates risk assessment.

Legal status varies by country. In some places, cardarine is controlled under medicines or psychoactive substances laws; in others, it may be sold with minimal oversight as a research chemical. Customs agencies have intercepted shipments, and several national health agencies have issued warnings about products marketed for bodybuilding or performance enhancement. The lack of a standardized pharmaceutical supply means identity, purity, and contamination levels can differ widely between samples. These factors make cardarine a regulatory and public health concern rather than a conventional prescription drug.

Cardarine at a glance

PropertyValueNotes
AppearanceWhite to off-white powderCommon for reference-grade material.
SolubilityLow in waterDissolves in DMSO and some organic solvents.
Typical storage-20 °C, desiccatedProtect from light and moisture.
Analytical methodLC-MS/MSUsed for trace detection in biological matrices.
Purity assessmentHPLC with UV detectionOften combined with NMR and mass spectrometry.

Mechanism and Safety Research

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.

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Regulation and Detection

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 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.

Identity and Regulatory Status

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.

Notes from published material

[M(H2O)6]n+ + 6 H2O* → [M(H2O*)6]n+ + 6 H2O where H2O* denotes isotopically enriched water, e.g., H217O The rates of water exchange varies by 20 orders of magnitude across the periodic table, with lanthanide complexes at one extreme and Ir(III) species being the slowest.

Political independence was not necessarily the foreordained outcome of the political turmoil in Spanish America. "There was little interest in outright independence." As historians R.A. Humphreys and John Lynch note, "it is all too easy to equate the forces of discontent or even the forces of change with the forces of revolution." Since "by definition, there was no history of independence until it happened," when Spanish American independence did occur, explanations for why it came about have been sought. The Spanish American Wars of Independence were essentially a power vacuum in the Spanish monarchy that resulting in a rupture that gave rise to new states.

=== Journal articles === —— (1927). "The Theoretical Prediction of the Physical Properties of Many-Electron Atoms and Ions. Mole Refraction, Diamagnetic Susceptibility, and Extension in Space". Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences. 114 (767): 181–211. Bibcode:1927RSPSA.114..181P. doi:10.1098/rspa.1927.0035. —— (1929). "The Principles Determining the Structure of Complex Ionic Crystals". Journal of the American Chemical Society. 51 (4): 1010–1026. Bibcode:1929JAChS..51.1010P. doi:10.1021/ja01379a006. —— (1931). "The Nature of the Chemical Bond. I. Application of Results Obtained from the Quantum Mechanics and from a Theory of Paramagnetic Susceptibility to the Structure of Molecules". Journal of the American Chemical Society. 53 (4): 1367–1400. Bibcode:1931JAChS..53.1367P. doi:10.1021/ja01355a027. —— (1931). "The Nature of the Chemical Bond. II. The One-Electron Bond and the Three-Electron Bond". Journal of the American Chemical Society. 53 (9): 3225–3237. Bibcode:1931JAChS..53.3225P. doi:10.1021/ja01360a004. —— (1932). "The Nature of the Chemical Bond. III. The Transition from One Extreme Bond Type to Another". Journal of the American Chemical Society. 54 (3): 988–1003. Bibcode:1932JAChS..54..988P. doi:10.1021/ja01342a022. —— (1932). "The Nature of the Chemical Bond. IV. The Energy of Single Bonds and the Relative Electronegativity of Atoms". Journal of the American Chemical Society. 54 (9): 3570–3582. Bibcode:1932JAChS..54.3570P. doi:10.1021/ja01348a011. ——; Wheland, G. W. (1933). "The Nature of the Chemical Bond. V.

=== Bones, joints, frailty, posture and in people at risk === Strength training also provides functional benefits. Stronger muscles improve posture, provide better support for joints, and reduce the risk of injury from everyday activities. Progressive resistance training may improve function, quality of life and reduce pain in people at risk of fracture, with rare adverse effects. Weight-bearing exercise also helps to prevent osteoporosis and to improve bone strength in those with osteoporosis. For many people in rehabilitation or with an acquired disability, such as following stroke or orthopaedic surgery, strength training for weak muscles is a key factor to optimise recovery. Consistent exercise can actually strengthen bones and prevent them from getting frail with age.

Sources: en.wikipedia.org

Background from the literature

Police Scotland arrest Scotland's former First Minister, Nicola Sturgeon, as part of their ongoing investigation into the SNP's finances. She is subsequently released without charge. 12 June Following a period of hot weather, thunderstorms and torrential rain bring flash flooding to parts of the UK. A mother-of-three is sentenced to 28 months in prison for inducing an abortion at home during 2020 with medication while she was 32–34 weeks pregnant. The medication was obtained following a remote consultation at which the woman misled doctors over the advancement of her pregnancy. 13 June 2023 Nottingham attacks: A major incident is declared in Nottingham, with much of the city centre cordoned off, following a vehicle-ramming and knife attack. A 31-year-old man is arrested on suspicion of multiple murders, following the deaths of three people including two university students, while three others are hospitalised. The first day of a public inquiry into the COVID-19 pandemic begins in central London. The inquiry's lead lawyer says "very little thought" was given about the impact of a national lockdown and that Brexit planning may have occupied too much of the government's time and resources, while a counsel for the Covid-19 Bereaved Families for Justice accuses the authorities of being "complacent". A heatwave is declared in several parts of the UK as temperatures reach 30 °C, and after exceeding 25 °C for three consecutive days; the UK's heat-health alert is also extended.

In chromatography, endcapping refers to the replacement of accessible silanol groups in a bonded stationary phase by trimethylsilyl groups. End-capped columns have much lower residual silanol group activity compared to non-endcapped columns. Endcapped columns show decreased retention for hydrogen bond acceptors, such as ionized bases, and increased retention for protonated bases.

=== Radiation offenses === The misuse of ionizing radiation is a radiation offence under German criminal law. The use of ionizing radiation to harm persons or property is punishable. Since 1998, the regulations can be found in § 309 StGB (in German) (previously § 311a StGB old version); the regulations go back to § 41 AtG old version. In the Austrian Criminal Code, relevant criminal offenses are defined in the seventh section, "Criminal acts dangerous to the public" and "Criminal acts against the environment". In Switzerland, endangerment by nuclear energy, radioactive substances or ionizing radiation is punishable under Art. 326 of the Swiss Criminal Code and disregard of safety regulations under Chapter 9 of the Nuclear Energy Act of 21 March 2003.

Sources: en.wikipedia.org

Frequently asked questions

How is cardarine measured in biological samples?

LC-MS/MS is common, often after sample cleanup. The assay targets GW501516 or its metabolites.

What storage conditions are typical for reference material?

Reference material is usually kept cold, dry, and protected from light. Frozen aliquots reduce repeated freeze-thaw cycles.

Why can purity vary between products?

No approved pharmaceutical product exists, so manufacturing and quality controls are not standardized. Products may contain different compounds or impurities.

Is cardarine approved for human use?

No. Major drug regulators have not approved GW501516 for treating any medical condition. Products sold as cardarine are typically unapproved research chemicals or supplements, so their contents and safety are not assured.

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