LC-MS/MS is one of those subjects where the details matter more than the headlines. This page pulls together the background, the mechanisms, and the practical points readers ask about most.
Updated 2026-01-14. Numbers and descriptions here follow the published literature rather than marketing material.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Regulatory status | Prohibited in sport; not approved as medicine | Listed by WADA at all times. |
| Common synonyms | GW501516, GW-501516, endurobol | Cardarine is a colloquial name. |
| Typical analytical method | LC-MS/MS | Detects parent compound and metabolites. |
| Common test matrix | Urine | Blood and dried blood spots also possible. |
| Legal classification | Varies by country | Often treated as unapproved drug or research chemical. |
Laboratory handling focuses on identity, purity, and stability. Reference standards are typically stored cold and dry, protected from light, because solutions can degrade over time. Analytical checks may use high-performance liquid chromatography with ultraviolet detection or mass spectrometry. Impurities and related substances can be separated chromatographically and compared with a known standard. Because cardarine is not an approved drug, compendial monographs are absent, and laboratories often rely on in-house methods. Reported purity varies among unregulated products and should not be assumed from a label.
GW501516 binds and activates PPARδ, a nuclear receptor that influences transcription of genes involved in fatty acid oxidation and energy use. Activation shifts some metabolic pathways in preclinical models, which is why the compound has been studied for lipid disorders and exercise-related endpoints. The exact downstream effects in humans are incompletely mapped. PPARδ is expressed in many tissues, including skeletal muscle, liver, and adipose tissue, so broad activation may have varied consequences. Researchers continue to examine how selective or partial activation might alter the balance between benefits and risks.
Published human data are sparse and mostly come from early-phase trials. Those studies examined short-term changes in lipids, glucose, and exercise capacity, but they were not large enough to establish efficacy or long-term safety. Some animal experiments reported increased running endurance, yet such findings do not prove a performance benefit in people. Anti-doping laboratories detect GW501516 and its metabolites in urine or blood using liquid chromatography-tandem mass spectrometry. Detection windows depend on dose, sample type, and individual metabolism. The method is sensitive enough to identify trace residues in tested samples.
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.
Despite its modern (Pharmacopoeia specified) standard structure, storage stability, potency, purity, and unit strength, with its narrow therapeutic index — i.e., difference between its minimum effective dose (MED) and toxic dose (TD) — and, as well, the small difference between its toxic dose and its lethal dose (LD), insulin remains a dangerous, high-alert medication (HAM).
=== Governmental districts (Regierungsbezirke) === The large states of Baden-Württemberg, Bavaria, Hesse, and North Rhine-Westphalia are divided into governmental districts, or Regierungsbezirke. In Rhineland-Palatinate, these districts were abolished or re-organized on 1 January 2000, in Saxony-Anhalt on 1 January 2004, and in Lower Saxony on 1 January 2005. From 1990 until 2012, Saxony was divided into three districts (called Direktionsbezirke since 2008). In 2012, these districts' authorities were merged into one central authority, the Landesdirektion Sachsen.
Since independence due to the partition of India, urbanisation has surged for various reasons. In the south, Karachi stands as the most populous commercial hub along the Indus River. In the east, west, and north, a dense population arc spans cities like Lahore, Faisalabad, Rawalpindi, Islamabad, Sargodha, Gujranwala, Sialkot, Gujrat, Jhelum, Sheikhupura, Nowshera, Mardan, and Peshawar. By 1990–2008, city dwellers constituted 36% of Pakistan's population, making it South Asia's most urbanised nation, with over 50% living in towns of 5,000+ inhabitants. Immigration, both domestic and international, significantly fuels urban growth. Migration from India, especially to Karachi, the largest metropolis, and from nearby countries, accelerates urbanisation, posing new political and socio-economic challenges. Economic shifts like the green revolution and political developments also play crucial roles.
== Detection == As of 2016, blood tests can identify flunitrazepam at concentrations of as low as 4 nanograms per millilitre; the elimination half-life of the drug is 4–12 hours. For urine samples, metabolites can be identified for 60 hours to 28 days, depending on the dose and analytical method used. Hair and saliva can also be analyzed; hair is useful when a long time has transpired since ingestion, and saliva for workplace drug tests. Flunitrazepam can be measured in blood or plasma to confirm a diagnosis of poisoning in hospitalized patients, provide evidence in an impaired driving arrest, or assist in a medicolegal death investigation. Blood or plasma flunitrazepam concentrations are usually in a range of 5–20 μg/L in persons receiving the drug therapeutically as a nighttime hypnotic, 10–50 μg/L in those arrested for impaired driving and 100–1000 μg/L in victims of acute fatal overdosage. Urine is often the preferred specimen for routine substance use monitoring purposes. The presence of 7-aminoflunitrazepam, a pharmacologically active metabolite and in vitro degradation product, is useful for confirmation of flunitrazepam ingestion. In postmortem specimens, the parent drug may have been entirely degraded over time to 7-aminoflunitrazepam. Other metabolites include desmethylflunitrazepam and 3-hydroxydesmethylflunitrazepam.
Sources: en.wikipedia.org
== History == Dimethocaine was originally synthesized by the Hoffmann-La Roche company in 1930. It was sold under the market name larocaine. During the 1930s dimethocaine gained popularity in the US as a local anesthetic. Just like cocaine and procaine, it was used during surgery, primarily in dentistry, ophthalmology and otolaryngology. However, in the 1940s, it was removed from the market because of its psychoactive effects and risk of addiction. Nowadays dimethocaine is abused for these psychoactive effects. It is sold as a cocaine surrogate to circumvent legislation issues.
=== Anticancer activity === Didymin has been studied for its effects on various cancer cell lines in vitro. In human hepatocellular carcinoma (HepG2) cells, it inhibited cell viability, migration, and colony formation, induced apoptosis, and caused G2/M cell cycle arrest. These effects were associated with changes in the Bcl-2/Bax ratio and activation of caspase-mediated apoptosis, as well as upregulation of Raf kinase inhibitor protein (RKIP) and suppression of the ERK/MAPK and PI3K/Akt pathways.
=== International response === The international community tends to react adversely to coups by reducing aid and imposing sanctions. A 2015 study finds that "coups against democracies, coups after the Cold War, and coups in states heavily integrated into the international community are all more likely to elicit global reaction." Another 2015 study shows that coups are the strongest predictor for the imposition of democratic sanctions. A third 2015 study finds that Western states react most strongly against coups of possible democratic and human rights abuses. A 2016 study shows that the international donor community in the post-Cold War period penalizes coups by reducing foreign aid. The US has been inconsistent in applying aid sanctions against coups both during the Cold War and post-Cold War periods, a likely consequence of its geopolitical interests. Organizations such as the African Union (AU) and the Organization of American States (OAS) have adopted anti-coup frameworks. Through the threat of sanctions, the organizations actively try to curb coups. A 2016 study finds that the AU has played a meaningful role in reducing African coups. A 2017 study found that negative international responses, especially from powerful actors, have a significant effect in shortening the duration of regimes created in coups. According to a 2020 study, coups increase the cost of borrowing and increase the likelihood of sovereign default.
Abnormal thyroid function—hypo- and hyperthyroidism—can manifest as myopathy with symptoms of exercise-induced muscle fatigue, cramping, muscle pain and may include proximal weakness or muscle hypertrophy (particularly of the calves). Hypothyroidism up-regulates glycogen synthesis and down-regulates glycogenolysis and glycolysis; conversely, hyperthyroidism does the reverse, up-regulating glycogenolysis and glycolysis while down-regulating glycogen synthesis. Prolonged hypo- and hyperthyroid myopathy leads to atrophy of type II (fast-twitch/glycolytic) muscle fibres, and a predominance of type I (slow-twitch/oxidative) muscle fibres. Muscle biopsy shows abnormal muscle glycogen: high accumulation in hypothyroidism and low accumulation in hyperthyroidism. Hypothyroid myopathy includes Kocher-Debre-Semelaigne syndrome (childhood-onset), Hoffman syndrome (adult-onset), myasthenic syndrome, and atrophic form. In patients with increased growth hormone, muscle biopsy includes, among other features, excess glycogen deposition. EPG5-related Vici syndrome is a multisystem disorder, a congenital disorder of autophagy, with muscle biopsy showing excess glycogen accumulation, among other myopathic features. It is interesting to note, in comparison to hypothyroid myopathy, that McArdle disease (GSD-V), which is by far the most commonly diagnosed of the muscle GSDs and therefore the most studied, has as its second highest comorbidity endocrine disease (chiefly hypothyroidism) and that some patients with McArdle disease also have hypertrophy of the calf muscles.
K a = [ H + ] [ A − ] [ HA ] {\displaystyle K_{a}={\frac {{\ce {[H+] [A^{-}]}}}{{\ce {[HA]}}}}} The stronger of two acids will have a higher Ka than the weaker acid; the ratio of hydrogen cations to acid will be higher for the stronger acid as the stronger acid has a greater tendency to lose its proton. Because the range of possible values for Ka spans many orders of magnitude, a more manageable constant, pKa is more frequently used, where pKa = −log10 Ka. Stronger acids have a smaller pKa than weaker acids. Experimentally determined pKa at 25 °C in aqueous solution are often quoted in textbooks and reference material. Arrhenius acids are named according to their anions. In the classical naming system, the ionic suffix is dropped and replaced with a new suffix, according to the table following. The prefix "hydro-" is used when the acid is made up of just hydrogen and one other element. For example, HCl has chloride as its anion, so the hydro- prefix is used, and the -ide suffix makes the name take the form hydrochloric acid. Classical naming system:
Sources: en.wikipedia.org
Legal status varies by country. It is not approved as a medicine, and it is prohibited in sport. Some jurisdictions restrict import, sale, or possession.
Laboratories use liquid chromatography-tandem mass spectrometry to detect GW501516 and its metabolites. Urine is commonly tested, and testing can occur in and out of competition.
No, cardarine is not a SARM. It is a PPARδ agonist, which acts on a different receptor. The two classes are often confused in online discussions.
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.