LC-MS/MS 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.
GW501516 acts as a ligand for PPAR delta, a nuclear receptor that regulates transcription of genes involved in fatty acid oxidation and energy use. Activation of this receptor in skeletal muscle shifts metabolism toward fat burning in animal models. The compound does not burn fat directly; it changes gene expression over hours to days. Researchers study it to understand metabolic flexibility and exercise adaptation. Effects observed in rodents are not automatically expected in humans.
Preclinical research reported that GW501516 increased running endurance in mice and improved lipid profiles in some animal species. Early human trials explored effects on high-density lipoprotein cholesterol, triglycerides, and glucose handling, but the program was discontinued. Published human data are sparse and do not establish efficacy for any condition. Studies also examined PPAR delta in cancer biology, with conflicting findings across models. The relationship between receptor activation, tissue context, and disease risk remains an active area of investigation.
Anti-doping laboratories identify GW501516 and its metabolites using liquid chromatography-tandem mass spectrometry. Urine is the usual matrix, and detection can occur after the parent compound has cleared from blood. The exact detection window depends on dose, formulation, individual metabolism, and assay sensitivity. Because the compound is prohibited at all times, athletes are subject to testing in and out of competition. Analytical methods continue to improve as new metabolites and designer analogs are characterized.
Cardarine is a common name for GW501516, a synthetic compound studied for its effects on lipid and glucose metabolism. It functions as an agonist at peroxisome proliferator-activated receptor delta, or PPARδ, a nuclear receptor that influences gene expression. The molecule is not a steroid, nor is it a selective androgen receptor modulator. It is also known in research and sports literature as GW-501516 and endurobol. Early laboratory work examined its metabolic activity in cell cultures and animal models.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular target | PPAR delta (NR1C2) | Ligand-activated nuclear receptor. |
| Primary tissues studied | Skeletal muscle, liver, adipose | Effects on fatty acid oxidation and energy use. |
| Typical detection matrix | Urine | Used in anti-doping analysis. |
| Common analytical method | LC-MS/MS | Detects parent compound and metabolites. |
| Sport regulatory class | Prohibited at all times | Listed as a metabolic modulator by WADA. |
Cardarine is a synthetic compound also known as GW501516, GW-501516, and sometimes endurobol. It was developed as a selective agonist of peroxisome proliferator-activated receptor delta, a nuclear receptor involved in fatty acid oxidation and energy metabolism. The compound was studied in preclinical models for metabolic and cardiovascular conditions, but it did not become a marketed human medicine. In regulatory and anti-doping contexts, it is treated as a prohibited substance rather than a licensed medicine.
The pharmacological interest in cardarine centers on PPARδ activation and its downstream effects on lipid handling and mitochondrial function. In animal studies, PPARδ agonists have been associated with changes in exercise endurance and fatty acid utilization, though results vary by model and protocol. Human data remain sparse, and the absence of large controlled trials limits conclusions about efficacy. Researchers often describe the compound as a tool for probing PPARδ biology rather than a proven therapeutic agent.
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.
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.
In addition it yielded interesting data in terms of who are the main downloaders of the AIDA program, and has also provided technical (computer) information which aided the release of a freeware upgrade to the software. A second study audited 2,437 separate downloads of the AIDA program. The Internet-based survey methodology was confirmed to be robust and reliable. Over a 7.5-month period (from mid-July 2000 to early March 2001) 2,437 responses were received. During the corresponding period 4,100 actual downloads of the software were independently logged via the same route at the AIDA Website — giving a response rate to this audit of 59.4%. Responses were received from participants in 61 countries — although over half of these (n 5 1,533; 62.9%) originated from the United States and United Kingdom. Of these responses 1,361 (55.8%) were received from people with diabetes and 303 (12.4%) from relatives of patients, with fewer responses from doctors, diabetes educators, students, nurses, pharmacists, and other end users. This study has confirmed the feasibility of using the Internet to survey, at no real cost, a large number of medical software downloaders / users. In addition, it yielded up-to-date and interesting data about who are the main downloaders of the AIDA program. A third study surveyed downloaders of a more recent release of the program (AIDA v4.3a). Over a 1-year period (from March 2001 to February 2002) in total 3,864 responses were received.
Since its foundation, the Treaties sought to enable people to pursue their life goals in any country through free movement. Reflecting the economic nature of the project, the European Community originally focused upon free movement of workers: as a "factor of production". However, from the 1970s, this focus shifted towards developing a more "social" Europe. Free movement was increasingly based on "citizenship", so that people had rights to empower them to become economically and socially active, rather than economic activity being a precondition for rights. This means the basic "worker" rights in TFEU article 45 function as a specific expression of the general rights of citizens in TFEU articles 18 to 21. According to the Court of Justice, a "worker" is anybody who is economically active, which includes everyone in an employment relationship, "under the direction of another person" for "remuneration". A job, however, need not be paid in money for someone to be protected as a worker. For example, in Steymann v Staatssecretaris van Justitie, a German man claimed the right to residence in the Netherlands, while he volunteered plumbing and household duties in the Bhagwan community, which provided for everyone's material needs irrespective of their contributions. The Court of Justice held that Mr Steymann was entitled to stay, so long as there was at least an "indirect quid pro quo" for the work he did. Having "worker" status means protection against all forms of discrimination by governments, and employers, in access to employment, tax, and social security rights.
=== PTEN hamartoma syndrome === PTEN hamartoma syndrome encompasses hamartomatous disorders characterized by genetic mutations in the PTEN tumor suppressor gene, including Cowden syndrome, Bannayan–Riley–Ruvalcaba syndrome, Proteus syndrome and Proteus-like syndrome. Absent or dysfunctional PTEN protein allows cells to over-proliferate, causing hamartomas. Cowden syndrome is an autosomal dominant genetic disorder characterized by multiple benign hamartomas (trichilemmomas and mucocutaneous papillomatous papules) as well as a predisposition for cancers of multiple organs including the breast and thyroid. Bannayan–Riley–Ruvalcaba syndrome is a congenital disorder characterized by hamartomatous intestinal polyposis, macrocephaly, lipomatosis, hemangiomatosis and glans penis macules. Proteus syndrome is characterized by nevi, asymmetric overgrowth of various body parts, adipose tissue dysregulation, cystadenomas, adenomas, vascular malformation.
Sources: en.wikipedia.org
=== Partnerships === In 2012, Safeway invested $350 million into retrofitting 800 locations with clinics that would offer in-store blood tests. After many missed deadlines and questionable results from a trial clinic at Safeway's corporate offices, the deal was terminated in 2015. In 2013, Theranos partnered with Walgreens to offer in-store blood tests at more than 40 locations. Although Theranos blood tests were reportedly used on drug trial patients for GlaxoSmithKline and Pfizer, both companies stated in October 2015 that there were no active projects with Theranos. In June 2016, Walgreens terminated its partnership with Theranos. In November 2016, it filed a suit against Theranos in federal court in Delaware for breach of contract. In June 2017, Theranos reported to investors that the suit, which originally sought $140 million in damages, was settled for less than $30 million. In March 2015, the Cleveland Clinic announced a partnership with Theranos to test its technology and decrease the cost of lab tests. In July 2015, Theranos became the lab-work provider for Pennsylvania insurers AmeriHealth Caritas and Capital Blue Cross. The same month, the Food and Drug Administration approved the use of the company's fingerstick blood testing device for the herpes simplex virus (HSV-1) outside a clinical laboratory setting. Theranos was named the 2015 Bioscience Company of the Year by the Arizona BioIndustry Association (AzBio).
== External links == IUPAC's "Glossary of Terms Used in Combinatorial Chemistry" ACS Combinatorial Science (formerly Journal of Combinatorial Chemistry) Combinatorial Chemistry Review "Molecular Diversity". metapress.com. Archived from the original on May 15, 2016. Combinatorial Chemistry and High Throughput Screening Combinatorial Chemistry: an Online Journal SmiLib - A free open-source software for combinatorial library enumeration GLARE - A free open-source software for combinatorial library design
Another formation with Tyrannosaurus remains is the Lance Formation of Wyoming. This has been interpreted as a bayou environment similar to today's Gulf Coast. The fauna was very similar to Hell Creek, but with Struthiomimus replacing its relative Ornithomimus. The small ceratopsian Leptoceratops also lived in the area. In its southern range, specifically based on remains discovered from the North Horn Formation of Utah, Tyrannosaurus rex lived alongside the titanosaur Utetitan, the ceratopsid Torosaurus and the indeterminate troodontids and hadrosaurids. Tyrannosaurus mcraeensis from the McRae Group of New Mexico coexisted with the ceratopsid Sierraceratops and possibly the titanosaur Alamosaurus. Potential remains identified as cf. Tyrannosaurus have also been discovered from the Javelina Formation of Texas, where the remains of the titanosaur (either Alamosaurus or Utetitan), the ceratopsid Bravoceratops, the pterosaurs Quetzalcoatlus and Wellnhopterus, and possible species of troodontids and hadrosaurids are found. Its southern range is thought to have been dominated by semi-arid inland plains, following the probable retreat of the Western Interior Seaway as global sea levels fell. Tyrannosaurus may have also inhabited Mexico's Lomas Coloradas Formation in Sonora. Though skeletal evidence is lacking, six shed and broken teeth from the fossil bed have been thoroughly compared with other theropod genera and appear to be identical to those of Tyrannosaurus. If true, the evidence indicates the range of Tyrannosaurus was possibly more extensive than previously believed.
Sources: en.wikipedia.org
It binds to and activates PPAR delta, a nuclear receptor that controls expression of genes related to fatty acid oxidation. This mechanism can alter energy metabolism in animal models. It is not a direct stimulant or fat-burning enzyme.
Early-stage trials examined lipid and glucose markers, but the development program was discontinued. Published human results are limited and do not support approved use for any indication. Claims of performance or health benefits remain unproven.
Yes. Laboratories use LC-MS/MS to detect GW501516 and its metabolites in urine. Detection depends on timing and sensitivity, but the substance is banned at all times.
Cardarine is a common name for GW501516, a synthetic PPARδ agonist. It is not a steroid or a selective androgen receptor modulator. It was developed and studied as a research compound for metabolic pathways.