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 2026-04-25. 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.
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.
| 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. |
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.
Published studies have examined GW501516 in animal models of obesity, insulin resistance, and exercise endurance. Early human trials reportedly ended, and development was discontinued after preclinical findings raised concerns about cancer in some rodent studies. Regulatory agencies have not approved cardarine for any medical use. Its availability through non-pharmaceutical channels raises questions about identity, purity, and legal status that are separate from its laboratory pharmacology. Those questions are often addressed through analytical testing rather than assumptions about product labels.
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.
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.
== Therapeutic effects == Serotonin, given orally at a dose of 100 mg, produced effects in humans including blood pressure changes, abdominal cramps, muscle aches, and a feeling of sedation. In contrast to psychedelic drugs like LSD, no hallucinogenic effects were reported. In other studies, serotonin, at low intravenous doses of 2 to 6 mg, had no effects on electroencephalogram (EEG) readings in humans. In accordance with the preceding findings, it has been stated that administration of serotonin in humans produces no psychoactive effects that cannot be attributed to anxiety by its profound peripheral adverse effects including circulatory disturbance, other autonomic effects, and vomiting. Intracerebroventricular injection of serotonin has been studied in patients with severe psychiatric conditions, but little information about its psychoactive effects is provided. It is thought that exogenous serotonin is too hydrophilic to cross the blood–brain barrier and has too poor of metabolic stability due to rapid metabolism by monoamine oxidase (MAO) such that it cannot produce drug-like central effects in humans with peripheral administration. However, close analogues of serotonin that are more lipophilic and metabolically stable, like bufotenin (N,N-dimethylserotonin), 5-MeO-DMT (N,N,O-trimethylserotonin), and 5-MeO-AMT (α,O-dimethylserotonin), among many others, are active and produce pronounced centrally mediated effects in humans.
== History == Following the discovery of iodine by Bernard Courtois in 1811, it has been broadly used for the prevention and treatment of skin infections, as well as the treatment of wounds. Iodine has been recognized as an effective broad-spectrum bactericide, and is also effective against yeasts, molds, fungi, viruses, and protozoans. Drawbacks to its use in the form of aqueous solutions include irritation at the site of application, toxicity, and the staining of surrounding tissues. These deficiencies were overcome by the discovery and use of PVP-I, in which the iodine is carried in a complexed form and the concentration of free iodine is very low. The product thus serves as an iodophor. PVP-I was discovered in 1955, at the Industrial Toxicology Laboratories in Philadelphia by H. A. Shelanski and M. V. Shelanski. They carried out tests in vitro to demonstrate anti-bacterial activity, and found that the complex was less toxic in mice than tincture of iodine. Human clinical trials showed the product to be superior to other iodine formulations.
The three substrates of this enzyme are (S)-1-pyrroline-5-carboxylic acid, reduced nicotinamide adenine dinucleotide (NADH), and a proton. Its products are L-proline and oxidised (NAD+). Nicotinamide adenine dinucleotide phosphate can be used as an alternative cofactor. This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-NH group of donors with NAD+ or NADP+ as acceptor. The systematic name of this enzyme class is L-proline:NAD(P)+ 5-oxidoreductase. Other names in common use include proline oxidase, L-proline oxidase, 1-pyrroline-5-carboxylate reductase, NADPH-L-Delta1-pyrroline carboxylic acid reductase, and L-proline-NAD(P)+ 5-oxidoreductase. This enzyme participates in arginine and proline metabolism.
Sources: en.wikipedia.org
MV Hondius hantavirus outbreak: The last American passenger exits the National Quarantine Unit at the University of Nebraska Medical Center, officially ending the quarantine for Americans who were affected by the hantavirus outbreak on the MV Hondius cruise ship. The Washington Post publishes an investigation into Tulsi Gabbard's relationship with Chris Butler and the Science of Identity Foundation, alleging that confidential memos from her congressional career showed outside political and policy guidance. Gabbard's office and representatives of the foundation reject the report, calling the allegations false and anti-Hindu bigotry. June 22 – In college baseball, the Oklahoma Sooners baseball team defeat the North Carolina Tar Heels to win the College World Series for the first time since their 1994 season. June 23 Iran war: The Senate, by a vote of 50–48, mandates the United States to either end its war operations or seek congressional consent to continue fighting. 2026 NBA draft: The 80th edition of the NBA draft is held at the Barclays Center, with the Washington Wizards selecting former Brigham Young University (BYU) freshman AJ Dybantsa with the first-overall pick. The 21st Century ROAD to Housing Act passes in the United States House of Representatives, sending it to President Trump for his signature. June 24 – President Trump cancels a planned signing ceremony for the bipartisan 21st Century ROAD to Housing Act, saying that he will not sign the bill until Congress passes the unrelated SAVE America Act, a voter identification and proof-of-citizenship bill.
Ketone bodies can be used as fuels, yielding 22 ATP and 2 GTP molecules per acetoacetate molecule when oxidized in the mitochondria. Ketone bodies are transported from the liver to other tissues, where acetoacetate and beta-hydroxybutyrate can be reconverted to acetyl-CoA to produce reducing equivalents (NADH and FADH2), via the citric acid cycle. Ketone bodies cannot be used as fuel by the liver, because the liver lacks the enzyme β-ketoacyl-CoA transferase, also called thiolase. Acetoacetate in low concentrations is taken up by the liver and undergoes detoxification through the methylglyoxal pathway which ends with lactate. Acetoacetate in high concentrations is absorbed by cells other than those in the liver and enters a different pathway via 1,2-propanediol. Though the pathway follows a different series of steps requiring ATP, 1,2-propanediol can be turned into pyruvate.
where M is molar mass of the radionuclide, and NA is the Avogadro constant. Practically, the mass number A of the radionuclide is within a fraction of 1 % of the molar mass expressed in g/mol and can be used as an approximation. Specific radioactivity a is defined as radioactivity per unit mass of the radionuclide:
Sources: en.wikipedia.org
== Complications == Solar purpura by itself does not cause any health complications. However, solar purpura does indicate thin skin and that a person is more prone to skin injuries. It is advised to take caution on preventing trauma to the skin since it is more prone to tears.
== Research == Azumolene is a 30-fold more water-soluble analog of dantrolene that also works to decrease the release of intracellular calcium by its action on the ryanodine receptor. In MH-susceptible swine, azumolene was as potent as dantrolene. It has yet to be studied in vivo in humans, but may present a suitable alternative to dantrolene in the treatment of MH.
A typical Indian meal is built on a plain cereal, complemented by savoury dishes. The cooked cereal could be steamed rice; chapati, a thin unleavened bread; idli, a steamed breakfast cake; or dosa, a griddled pancake. The savoury dishes might include lentils, pulses, vegetables, meat, poultry and fish commonly spiced with ginger and garlic, but also coriander, cumin, turmeric, cinnamon, cardamom and others. In some instances, the ingredients may be mixed during the cooking process. India has distinctive vegetarian cuisines, each a feature of the geographical and cultural histories of its communities. About 20% to 39% of India's population consists of vegetarians. Although meat is eaten widely, the proportional consumption of meat is low. The most significant import of cooking techniques into India during the last millennium occurred during the Mughal Empire, spreading into northern India from regions to its northwest, along with dishes such as pilaf. Onions, garlic, almonds, and spices were added to the simple yogurt marinade of Persia. Rice was partially cooked and layered alternately with sauteed meat, the pot sealed tightly, and slow cooked according to another Persian cooking technique, to produce biryani, a feature of festive dining in many parts of India. The diversity of Indian food served worldwide has been partially concealed by the dominance of Punjabi cuisine.
=== Bone tumors === Benign tumors of bone can be similar macroscopically and require a combination of a clinical history with cytogenetic, molecular, and radiologic tests for diagnosis. Three common forms of benign bone tumors with are giant cell tumor of bone, osteochondroma, and enchondroma; other forms of benign bone tumors exist but may be less prevalent.
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.
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.