This is a working overview of LC-MS/MS, written for readers who want more than a one-paragraph summary but less than a textbook.
Reviewed 2025-11-26. Anything still debated is marked as such rather than presented as settled.
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.
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.
Cardarine is a common name for GW501516, also GW-1516, a synthetic compound developed as a peroxisome proliferator-activated receptor delta (PPARδ) agonist. It belongs to a class of agents that modulate gene transcription related to lipid and energy metabolism. The compound was studied in preclinical and early clinical research for metabolic and cardiovascular conditions, but it did not progress to approved therapeutic use. Its name appears in fitness and sports contexts despite not being approved as a drug.
PPARδ is a nuclear receptor that influences transcription of genes involved in fatty acid oxidation, lipid transport, and energy homeostasis. GW501516 binds and activates this receptor with high selectivity relative to PPARα and PPARγ in laboratory assays. Activation alters expression of target genes in skeletal muscle, liver, and adipose tissue in animal models. The exact clinical consequences of these changes in humans remain incompletely characterized, and observed effects in animals do not establish therapeutic benefit or safety.
| Property | Value | Notes |
|---|---|---|
| WADA classification | S4 Hormone and Metabolic Modulators | Prohibited at all times in sport. |
| Drug approval status | Not approved in major jurisdictions | No accepted therapeutic indication. |
| Common detection method | LC-MS/MS | Detects parent compound and metabolites. |
| Typical test matrix | Urine or blood | Urine is common in anti-doping testing. |
| Product labeling | Research chemical or supplement | Often not independently verified. |
Laboratory studies have examined GW501516 in cell cultures and rodents for conditions such as dyslipidemia, insulin resistance, and obesity. Some trials in humans were initiated, but development was discontinued after preclinical findings raised concerns about cancer in certain models. Those findings do not prove that the compound causes cancer in people, but they contributed to regulatory caution. Later reviews often describe the evidence as preliminary and insufficient for assessing long-term safety.
In the fitness and bodybuilding literature, cardarine is frequently discussed as an endurance agent or fat-loss compound, although such claims are not supported by robust clinical evidence. Online descriptions often mix animal data, user anecdotes, and marketing language. Researchers who study PPARδ agonists distinguish between receptor activation in controlled experiments and unsupervised use of unverified products. The latter introduces unknown purity, dose, and interactions, making reported experiences difficult to interpret scientifically.
GW501516 acts as an agonist at peroxisome proliferator-activated receptor delta, a nuclear receptor involved in transcription of genes related to lipid handling and energy use. Activation of PPARδ can shift skeletal muscle toward greater fatty acid oxidation in animal models, which is one reason it drew interest for metabolic disease and exercise research. The exact downstream effects depend on tissue, species, dose, and duration. Human data are sparse, so many proposed benefits remain hypotheses rather than established clinical outcomes.
Cardarine is a common name for GW501516, a synthetic compound first described in the 1990s as a selective agonist of the peroxisome proliferator-activated receptor delta. It was studied in preclinical models for metabolic and cardiovascular conditions, but it has not been approved as a medicine in the United States, Europe, or other major jurisdictions. Retail products labeled as cardarine are generally research chemicals or supplements, not pharmaceutical formulations. Because human safety and efficacy data remain limited, regulatory agencies treat it as an unapproved substance rather than a therapeutic product.
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.
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.
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.
== History == Tacrolimus was discovered in 1987 by a Japanese team led by pharmacologist Tohru Kino; it was among the first macrolide immunosuppressants discovered, preceded by the discovery of rapamycin (sirolimus) on Rapa Nui (Easter Island) in 1975. It is produced by a soil bacterium, Streptomyces tsukubensis. The name tacrolimus is derived from "Tsukuba macrolide immunosuppressant". The early development (investigational new drug phase) of tacrolimus, called at the time by the development code FK-506, happened in the next several years. A firsthand account of that process is given in Thomas Starzl's 1992 memoir. Tacrolimus was first approved by the US Food and Drug Administration (FDA) in 1994, for use in liver transplantation; the indications were extended to include kidney transplants. The first generic version of tacrolimus (capsule for oral route) was approved in the US in 2009. A generic version of tacrolimus for injection was approved in the US in 2017. Tacrolimus was approved for medical use in the European Union in 2002, for the treatment of moderate to severe atopic dermatitis. In 2007, the indications were expanded to include the prophylaxis of transplant rejection in adult kidney or liver allograft recipients and the treatment of allograft rejection resistant to treatment with other immunosuppressive medicinal products in adults.
Because a breast implant is a Class III medical device of limited product-life, the principal rupture-rate factors are its age and design; nonetheless, a breast implant device can retain its mechanical integrity for decades in a woman's body. When a saline breast implant ruptures, leaks, and empties, it quickly deflates, and thus can be readily explanted (surgically removed). In some cases, saline implant rupture can result in an infection due to bacteria or mold that had been within the implant, though this is uncommon. The follow-up report, Natrelle Saline-filled Breast Implants: a Prospective 10-year Study (2009) indicated rupture-deflation rates of 3–5 per cent at 3-years post-implantation, and 7–10 per cent rupture-deflation rates at 10-years post-implantation. In a study of his 4761 augmentation mammaplasty patients, Eisenberg reported that overfilling saline breast implants 10-13% significantly reduced the rupture-deflation rate to 1.83% at 8-years post-implantation.
Brec Bassinger as Courtney Whitmore / Stargirl:A high school student from Los Angeles who finds a powerful weapon, the Cosmic Staff, and becomes the superheroine Stargirl. As Stargirl, she also becomes the leader of the second incarnation of the Justice Society of America (JSA). In preparation for the role, Bassinger did not look at the character's previous portrayals by Britt Irvin on Smallville and Sarah Grey on Legends of Tomorrow because they were depicted as "older, more mature version[s]" of Stargirl. Bassinger added that the series follows the comic Stars and S.T.R.I.P.E. more "in that she's young, high school, naive", which she wanted to bring that into her version of Stargirl. Maizie Smith portrays a five-year old Courtney. Yvette Monreal as Yolanda Montez / Wildcat II:A once popular student at Blue Valley High until a scandal made her an outcast and a disgrace to her Catholic parents. A skilled boxer, she becomes one of Courtney's friends and a member of the new JSA as the new Wildcat. Anjelika Washington as Beth Chapel / Doctor Mid-Nite II: A social reject and nerd who becomes one of Courtney's friends and a member of the new JSA as the new Doctor Mid-Nite. Cameron Gellman as Rick Tyler / Hourman II:A high school delinquent with anger issues and the son of the original Hourman whose parents were killed in a staged car accident when he was seven. He becomes one of Courtney's friends and a member of the new JSA as the new Hourman. Boston Pierce portrays a 7-year-old Rick. Trae Romano as Mike Dugan: Pat Dugan's son and Courtney's stepbrother.
Sources: en.wikipedia.org
Fibronectin type III domain-containing protein 5, the precursor of irisin, is a type I transmembrane glycoprotein that is encoded by the FNDC5 gene. Irisin is a cleaved version of FNDC5, named after the Greek messenger goddess Iris. Fibronectin domain-containing protein 5 is a membrane protein comprising a short cytoplasmic domain, a transmembrane segment, and an ectodomain consisting of a ~100 kDa fibronectin type III (FNIII) domain.
During 1962, SWAPO had emerged as the dominant nationalist organisation for the Namibian people. It co-opted other groups such as the South West Africa National Union (SWANU), and later in 1976 the Namibia African People's Democratic Organisation. SWAPO used guerrilla tactics to fight the South African Defence Force. On 26 August 1966, the first major clash of the conflict took place, when a unit of the South African Police, supported by the South African Air Force, exchanged fire with SWAPO forces. This date is generally regarded as the start of what became known in South Africa as the Border War. One important factor in the fight for independence was the 1971-72 Namibian contract workers strike, which fought for the elimination of the contract labour system and independence from South Africa. An underlying goal was the promotion of independence under SWAPO leadership. In 1973, the United Nations General Assembly recognised SWAPO as the 'sole legitimate representative' of Namibia's people. The Norwegian government began giving aid directly to SWAPO in 1974. The country of Angola gained its independence on 11 November 1975 following its war for independence. The leftist Popular Movement for the Liberation of Angola (MPLA), supported by Cuba and the Soviet Union, came to power. In March 1976, the MPLA offered SWAPO bases in Angola for launching attacks against the South African military.
== Antiquity == The first attempts at general anesthesia were probably herbal remedies administered in prehistory. Alcohol is the oldest known sedative; it was used in ancient Mesopotamia thousands of years ago.
Later on, however, Jean Améry—who had been tortured at Auschwitz—would sharply object that Adorno, rather than addressing such political concerns, was exploiting Auschwitz for his metaphysical phantom "absolute negativity" ("absolute Negativität"), using a language intoxicated by itself ("von sich selber bis zur Selbstblendung entzückte Sprache"). Adorno contended that the culture industry, through mass media, especially radio, had contributed to the development of fascism in Germany. In his view, the "authoritarian voice" arises from the intimacy of broadcast and social practices of radio listening. According to Adorno, "The authority of radio becomes greater the more it addresses the listener in his privacy," while "an organized mass of listeners might feel their own strength and even rise to a sort of opposition."
Sources: en.wikipedia.org
== Pharmacodynamics == Cinnarizine is classified as a selective antagonist of T-type voltage-operated calcium ion channels, because its binding blocks the channels and keeps them inert. It has a Ki (inhibitory constant) value of 22 nM. It is also known to have antihistaminic, antiserotoninergic and antidopaminergic effects, binding to H1 histamine receptors, and dopaminergic (D2) receptors. The IC50 (half-maximal inhibitory concentration) of cinnarizine for smooth muscle contraction inhibition is 60 mM and it has been shown that this drug preferentially binds to its target calcium channels when they are in an open, as opposed to closed conformation. In treatment of nausea and motion sickness it was previously hypothesized that cinnarizine exerts its effects by inhibiting the calcium currents in voltage gated channels in type II vestibular hair cells within the inner ear. However, more recent evidence supports the idea that at pharmacologically relevant levels (0.3–0.5 μM), cinnarizine is not lessening vestibular vertigo by blocking calcium channels, but rather by inhibiting potassium (K+) currents that are activated by heightened hydrostatic pressure on the hair cells. It is true that cinnarizine does abolish calcium currents in vestibular hair cells as well; it is just that this only occurs at higher concentrations of drug (3 μM). The inhibition of these currents works to lessen the vertigo and motion-induced nausea by dampening the over-reactivity of the vestibular hair cells, which send information about balance and motion to the brain.
Independent of strength and performance measures, muscles can be induced to grow larger by a number of factors, including hormone signaling, developmental factors, strength training, and disease. Contrary to popular belief, the number of muscle fibres cannot be increased through exercise. Instead, muscles grow larger through a combination of muscle cell growth as new protein filaments are added along with additional mass provided by undifferentiated satellite cells alongside the existing muscle cells. Biological factors such as age and hormone levels can affect muscle hypertrophy. During puberty in males, hypertrophy occurs at an accelerated rate as the levels of growth-stimulating hormones produced by the body increase. Natural hypertrophy normally stops at full growth in the late teens. As testosterone is one of the body's major growth hormones, on average, men find hypertrophy much easier to achieve than women. Taking additional testosterone or other anabolic steroids will increase muscular hypertrophy. Muscular, spinal and neural factors all affect muscle building. Sometimes a person may notice an increase in strength in a given muscle even though only its opposite has been subject to exercise, such as when a bodybuilder finds her left biceps stronger after completing a regimen focusing only on the right biceps. This phenomenon is called cross education.
The analysis of the debris at the 10-megaton Ivy Mike nuclear test was a part of long-term project. One of the goals was studying the efficiency of production of transuranic elements in high-power nuclear explosions. The motive for these experiments was that synthesis of such elements from uranium requires multiple neutron capture. The probability of such events increases with the neutron flux, and nuclear explosions are the most powerful man-made neutron sources, providing densities of the order 1023 neutrons/cm2 within a microsecond, or about 1029 neutrons/(cm2·s). In comparison, the flux of HFIR is 5×1015 neutrons/(cm2·s). A dedicated laboratory was set up right at Enewetak Atoll for preliminary analysis of debris, as some isotopes could have decayed by the time the debris samples reached the mainland U.S. The laboratory was receiving samples for analysis as soon as possible, from airplanes equipped with paper filters which flew over the atoll after the tests. Whereas it was hoped to discover new chemical elements heavier than fermium, none of these were found even after a series of megaton explosions conducted between 1954 and 1956 at the atoll. The atmospheric results were supplemented by the underground test data accumulated in the 1960s at the Nevada Test Site, as it was hoped that powerful explosions in a confined space might give improved yields and heavier isotopes.
Sources: en.wikipedia.org
Anti-doping laboratories typically use LC-MS/MS to detect GW501516 and its metabolites in urine. The method is sensitive and can identify the compound at low concentrations. Detection depends on sample timing, metabolism, and the specific assay.
Legality varies by country and context. It lacks marketing approval as a medicine in major countries. Sports organizations prohibit its use at all times.
A certificate of analysis may report identity, purity, and testing methods for a specific batch. It does not guarantee safety or legal status. Independent verification can confirm whether the material matches the label.
Cardarine is commonly known as GW501516 or GW-1516. These names refer to the same synthetic compound. It is not a brand-name approved medicine.