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.
Last reviewed on 2026-03-22. Where a claim depends on a specific study, the study is described rather than over-claimed.
GW501516 acts on PPARδ, a nuclear receptor that helps regulate fatty acid oxidation and energy homeostasis. In animal studies, activation of this receptor was associated with increased endurance and changes in lipid metabolism. Human trials examined effects on blood lipids and other metabolic markers, but the compound did not advance to approval. Rodent studies later reported tumors in multiple tissues at doses used in those experiments. Whether those findings translate to human risk remains uncertain, and the clinical relevance of the animal data is still debated.
Regulatory bodies treat GW501516 as a prohibited substance in competitive sport. The World Anti-Doping Agency added it to the prohibited list, and it falls under classes covering metabolic modulators and hormone-related agents. It is not approved by drug regulators for human use, and it is not a lawful dietary supplement. Products sold under the cardarine name may contain unlisted ingredients or different compounds. Because no approved product exists, quality and identity are not guaranteed by pharmaceutical manufacturing standards.
Cardarine is the common name for GW501516, a synthetic compound studied as a peroxisome proliferator-activated receptor delta agonist. Researchers developed it to explore treatments for lipid disorders and metabolic conditions. It is not an approved medicine in any country. Early clinical work examined changes in HDL cholesterol and triglycerides, but development was discontinued after animal studies raised concerns about cancer. The compound remains available as a research chemical and appears in discussions of performance enhancement.
At the molecular level, GW501516 binds and activates PPARδ, a nuclear receptor that regulates transcription. Activation shifts expression of genes involved in fatty acid oxidation, energy expenditure, and lipid transport in skeletal muscle and liver. Animal studies report increased endurance and altered lipid profiles after exposure. Human data are limited to small trials and do not establish long-term safety or efficacy. PPARδ also has roles in cell proliferation, so the relationship between activation and cancer risk remains an open question.
| Property | Value | Notes |
|---|---|---|
| Common name | Cardarine | Common internet and media name. |
| Research code | GW501516 | Also written GW-1516. |
| Drug class | PPARδ agonist | Not a selective androgen receptor modulator. |
| Development status | Discontinued | Clinical development halted after rodent cancer findings. |
| Regulatory status | Prohibited in sport | Listed by WADA; not approved as medicine. |
GW501516 acts as a selective agonist at PPARδ, a nuclear receptor that regulates transcription of genes involved in lipid handling and energy metabolism. Activation of PPARδ in preclinical models increases fatty acid oxidation, mitochondrial biogenesis, and exercise endurance in rodents. These effects have made the compound a subject of metabolic research and also a target for sport anti-doping rules. In humans, however, controlled studies are limited, and whether similar endurance or metabolic changes occur at tolerated exposures remains an open question. The receptor’s broad tissue distribution also means downstream effects may vary by organ and condition.
Detection of GW501516 in biological samples generally relies on liquid chromatography coupled with tandem mass spectrometry. Urine is a common matrix in anti-doping analysis, while blood or plasma may be used in research settings. Sample preparation can involve enzymatic hydrolysis, protein precipitation, or solid-phase extraction before instrumental analysis. Because the compound undergoes metabolism, assays may target the parent molecule, one or more metabolites, or both. Detection windows are not fixed; they depend on factors such as dose, route, individual metabolism, and assay sensitivity. Reference standards are required for accurate identification and quantification.
Handling and quality assessment of cardarine reference material follow general laboratory practices for poorly characterized compounds. It typically appears as a white to off-white powder and is sparingly soluble in water but soluble in organic solvents such as dimethyl sulfoxide and ethanol. Storage recommendations usually specify a cool, dry, dark place, with long-term storage at low temperature and desiccation. Purity may be checked by high-performance liquid chromatography with ultraviolet detection, while identity is confirmed by mass spectrometry and nuclear magnetic resonance. No pharmacopeial monograph exists, so reported purity and stability depend on the supplier’s methods.
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.
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.
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.
"In order to avoid possible health risks, the German Federal Office for Radiation Protection recommends that you minimize your personal exposure to radiation through your own initiative." As of 2016, the EMF Guideline 2016 of EUROPAEM (European Academy For Environmental Medicine) on the prevention, diagnosis and treatment of EMF-related complaints and diseases applies.
=== National Institute of Standards and Technology === As of 2018 NIST does not provide certificates for the common stable isotope reference materials. As seen at this link showing the light stable isotope references currently available from NIST, this category includes all of the isotopic references critical for isotopic measurement of hydrogen, carbon, oxygen, nitrogen, and sulfur. However, for most of these materials NIST does provide a report of investigation, which gives a reference value that is not certified (following the definitions of May et al. (2000)). For the above examples of USGS34 and USGS35, NIST reports reference values but has not certified the results of Böhlke et al. (2003). Conversely, NIST has not provided a reference value for IAEA-SO-5. As seen at this link, NIST does certify isotopic reference materials for non-traditional "heavy" isotopic systems including rubidium, nickel, strontium, gallium, and thallium, as well as several isotopic systems that would normally be characterized at "light" but non-traditional such as magnesium and chlorine. While the isotopic composition of several of these materials were certified in the mid-1960s, other materials were certified as recently as 2011 (for example, Boric Acid Isotopic Standard 951a).
Avenir Suisse, founded in 1999 by fifteen of the largest Swiss companies. It is supported by over 130 companies to date. DCAF, the Geneva Centre for the Democratic Control of Armed Forces, founded in 2000 to research security sector governance and reform. Gottlieb Duttweiler Institute (GDI), conceived by Migros-founder Gottlieb Duttweiler in 1946. Horasis, which hosts the annual Horasis Global Meeting Liberal Institute, founded in 1979.
Sources: en.wikipedia.org
=== mz5 === The mz5 format addresses the performance problems present in other XML based formats (such as the above ones). It uses mzML's ontology, but saves the data using the HDF5 backend for reduced storage space requirements and improved read/write speed.
== Further reading == Gollner, Adam J. (2010). The Fruit Hunters: A Story of Nature, Adventure, Commerce, and Obsession. Scribner. ISBN 978-0-7432-9695-3. Watson, R. R., and Preedy, V.R. (2010, eds.). Bioactive Foods in Promoting Health: Fruits and Vegetables. Academic Press. ISBN 978-0-12-374628-3.
Construction materials The chambers are generally built of brick masonry, or hollow cement-concrete slabs. Sheet metal or prefabricated aluminium in a double-walled construction with sandwiched thermal insulation, such as glass wool or polyurethane foams, are materials that are also used in some modern timber ovens. However, brick masonry chambers, with lime and (mortar) plaster on the inside and painted with impermeable coatings, are used widely and have been found to be satisfactory for many applications. Heating Heating is usually carried out by steam heat exchangers and pipes of various configurations (e.g. plain, or finned (transverse or longitudinal) tubes) or by large flue pipes through which hot gases from a wood-burning furnace are passed. Only occasionally is electricity or gas employed for heating. Humidification Humidification is commonly accomplished by introducing live steam into the kiln through a steam spray pipe. In order to limit and control the humidity of the air when large quantities of moisture are being rapidly evaporated from the timber, there is normally a provision for ventilation of the chamber in all types of kilns. Air circulation Air circulation is the means for carrying the heat to and the moisture away from all parts of a load. Forced circulation kilns are most common, where the air is circulated by means of fans or blowers, which may be installed outside the kiln chamber (external fan kiln) or inside it (internal fan kiln).
Sources: en.wikipedia.org
Shānghán Zábìng Lùn (傷寒雜病論), or The Treatise on Cold Damage and Miscellaneous Diseases, is the first Chinese monograph on diseases by Zhang Zhongjing. The original work is lost, but most of its contents are preserved in two extant works called Shānghán Lùn (傷寒論; "The Treatise on Cold Damage") and Jīnguì Yàolüè (金匱要略; "Essential Prescriptions from the Golden Chamber"). The first work primarily addresses externally triggered conditions while the latter work describes internally generated conditions. Zhang's specialized chapter on xiāo kě is found in Shānghán Lùn and Jīnguì Yàolüè. Nine subsections and nine formulae (herbal remedies) on wasting-thirst were recorded. The text proposed a theory of "three wasting-thirsts": upper- (associated with the lungs), middle- (associated with the stomach), and lower- (associated with the kidneys), all three of which shared excessive urine and thirst as symptoms. This theory was later expanded through the works of Liu Wansu (1120–1200 AD) and Wang Kentang (1549–1613 AD). According to Liu, "lower wasting-thirst" attributed to "kidney-yin deficiency" was associated with sweet urine (glycosuria). This may indicate differentiation akin to modern-day differentiation of diabetes mellitus and diabetes insipidus.
== History == The first IUD was developed in 1909 by the German physician Richard Richter of Waldenburg. Unlike modern intrauterine devices, early interuterine (from Latin inter-, meaning "between", as opposed to intra-) devices crossed both the vagina and the uterus, causing a high rate of pelvic inflammatory disease. Ernst Gräfenberg, another German physician (after whom the G-spot is named), created the first Ring IUD, Gräfenberg's ring, made of silver filaments. His work was suppressed during the Nazi regime, when contraception was considered a threat to Aryan women. In 1935, Gräfenberg, who was Jewish, was in jail in Berlin and Margaret Sanger paid a ransom to have him released. He moved to the United States and opened a private practice in New York, New York. His colleagues H. Hall and M. Stone took up his work after his death and created the stainless steel Hall-Stone Ring. Dr. Jack Lippes helped begin the increase of IUD use in the United States in the late 1950s. In this time, thermoplastics, which can bend for insertion and retain their original shape, became the material used for first-generation IUDs. Lippes also devised the addition of the nylon string to facilitate IUD removal. Lippes and his friend Paul Bronnenkant, a plastics developer, crafted the first Lippes Loop in Bronnenkant's kitchen, heating and molding the plastic on cookie sheets in the oven. His trapezoid-shaped Lippes Loop IUD became one of the most popular first-generation IUDs. In the following years, many different-shaped plastic IUDs were invented and marketed.
On August 21, 2018, In-N-Out announced plans to open a location in the Willamette Valley in Keizer. This was the company's northernmost location. On November 30, 2017, the company announced plans to build a production facility and distribution center in Colorado Springs, ahead of an expansion into Colorado, which is scheduled to be completed in 2021. The first Colorado locations opened in Colorado Springs and Aurora on November 20, 2020. In-N-Out received approval for a new distribution center to open in Chino, California, in 2020, taking some of the load off the long-standing Baldwin Park distribution center. The center opened later that year. On November 24, 2020, In-N-Out signaled that it was in the early stages of opening a store in Idaho. The first store in the state opened in Meridian in December 2023. In-N-Out later expressed interest in opening additional stores in Boise and Nampa, as well as a second location in Meridian. The company pursued various locations around Portland, Oregon, which were rejected or stalled due to development issues; a location in Ridgefield, Washington, the first in Washington state, was announced in 2024. The location in Ridgefield, Washington opened on August 20, 2025, becoming the first in the state. A second Washington state location opened on April 23, 2026 in Vancouver, Washington. A location in Hillsboro, Oregon is expected to open in June 2026.
At birth, the liver comprises roughly 4% of body weight and weighs on average about 120 g (4 oz). Over the course of further development, it will increase to 1.4–1.6 kg (3.1–3.5 lb) but will only take up 2.5–3.5% of body weight. Hepatosomatic index (HSI) is the ratio of liver weight to body weight.
Sources: en.wikipedia.org
No. Cardarine is a PPARδ agonist, while selective androgen receptor modulators act on androgen receptors. The two classes differ in receptor target and downstream effects.
Preclinical rodent studies reported cancers, including liver and bladder tumors, at tested doses. The human relevance of those findings is uncertain, but development was discontinued. No approved human product resulted.
No. It remains an investigational compound without approved therapeutic labeling. Sports regulators prohibit its use, and health agencies have warned against consuming it.
Cardarine is a common name for the investigational compound GW501516. It acts as a PPARδ agonist and is not approved for human use. It is prohibited in sport.