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 2025-12-09. Anything still debated is marked as such rather than presented as settled.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Appearance | White to off-white solid | Typical form of reference material |
| Solubility | Low in water; soluble in DMSO | Used to prepare stock solutions |
| Typical storage | -20 °C, desiccated, protected from light | Common laboratory practice |
| Analytical method | LC-MS/MS | Detects parent compound and metabolites |
| Common test matrix | Urine or blood | Used in anti-doping analysis |
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 the investigational chemical GW501516, also written GW-1516. It was developed as a peroxisome proliferator-activated receptor delta agonist for metabolic conditions such as dyslipidemia. Early research focused on lipid handling and energy use in skeletal muscle and other tissues. The compound was never approved as a medicine. In public discussion, it is often grouped with performance-enhancing substances, although its receptor target differs from that of anabolic steroids or selective androgen receptor modulators. Regulatory and health authorities have issued warnings about its use.
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.
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.
depends on temperature in a non-trivial way, and simple kinetic arguments as used here are inadequate. More fundamentally, the notion of a mean free path becomes imprecise for particles that interact over a finite range, which limits the usefulness of the concept for describing real-world gases.
Marlowe (1988), creator of Castle; writer of Air Force One, End of Days, and Hollow Man Lawrence Trilling (1988), showrunner of Parenthood and Goliath Maiken Baird (1989), documentary film producer, Client 9: The Rise and Fall of Eliot Spitzer Sam Bisbee (1990), Emmy Award-winning producer and composer Gina Fattore (1990), producer and writer of Dawson's Creek, Gilmore Girls, Parenthood, creator of Dare Me Jeff Rake (1990), television producer, writer of Boston Legal and creator of Manifest and The Mysteries of Laura Dede Gardner (1990), Academy Award-winning producer of 12 Years a Slave; president of Plan B Entertainment Jenji Kohan (1991), television writer, producer, creator of Orange Is the New Black and Weeds Ari Gold (1992), filmmaker, director of Adventures of Power Elizabeth Craft (1993), producer, screenwriter, Fantasy Island, The 100, Lie to Me Ethan McSweeny (1993), former artistic director of the American Shakespeare Center, recipient of a 2018 Helen Hayes Award Brian Yorkey (1993), playwright, co-winner of the 2010 Pulitzer Prize for Drama for writing the musical Next to Normal Anna Winger (1993), screenwriter, creator of miniseries Deutschland 83, Deutschland 86, and Unorthodox Imara Jones (1994), political journalist and director Nicole Kassell (1994), director and producer of Watchmen, winner of the 2020 Directors Guild of America Award for Outstanding Directing – Drama Series Tim Carvell (1995), head writer of The Daily Show and executive producer of Last Week Tonight with John Oliver Josh Fox (1995), Academy Award-nominated documentary director, Gasland Adam Egypt Mortimer (1995), director of Daniel Isn't Real, Archenemy Henry Alex Rubin (1995), Academy Award-nominated director, Murderball Julius Sharpe (1995), television writer and showrunner of Making History and United We Fall Ramin Bahrani (1996), writer-director of Man Push Cart, Chop Shop and Fahrenheit 451, 2021 Academy Award for Best Adapted Screenplay nominee Moira Demos (1996), filmmaker who produced Netflix documentary Making a Murderer Yana Gorskaya (1996), Academy Award-nominated film editor, Spellbound Cetywa Powell (1996), director and fine art photographer Courtney Lilly (1997), television producer, showrunner of Black-ish, Grown-ish, Mixed-ish Nancy Schwartzman (1997), director, Roll Red Roll Beau Willimon (1999), creator and producer of House of Cards; writer of the play Farragut North Vikram Gandhi (2000), director, Kumaré, Barry, reporter for Vice Andrew Goldberg (2000), creator of Netflix series Big Mouth Ned Benson (2001), director, The Disappearance of Eleanor Rigby Dan Harris (2001), Saturn Award-winning screenwriter, X2, Superman Returns; director, Imaginary Heroes Andrew Neel (2001), filmmaker, director of King Kelly, Goat Anna Boden (2002), co-writer of Half Nelson and director of Sugar, Captain Marvel Tze Chun (2002), award-winning director, Children of Invention Lang Fisher (2002), co-creator of Never Have I Ever, writer of 30 Rock and Brooklyn Nine-Nine, Peabody Award winner in 2008 Susanna Fogel (2002), Emmy Award and BAFTA Award-nominated director Will Graham (2002), creator of the Onion News Network, showrunner of Mozart in the Jungle, Peabody Award winner in 2008 Ashley Lyle (2002), screenwriter, showrunner of Yellowjackets Justin Marks (2002), screenwriter, The Jungle Book, Counterpart Katori Hall (2003), playwright, The Mountaintop, winner of the 2021 Pulitzer Prize for Drama Raamla Mohamed (2003), Emmy Award-nominated screenwriter, Little Fires Everywhere Graham Moore (2003), winner of the 2015 Academy Award for Best Adapted Screenplay for his screenplay of The Imitation Game Lucia Aniello (2004), director of Rough Night and Time Traveling Bong Gabe Liedman (2004), creator of Q-Force, writer of Brooklyn Nine-Nine, PEN15, Inside Amy Schumer and Kroll Show Zhang Mo (2005), Chinese director, daughter of Zhang Yimou Laura Goode (2006), author, columnist, and producer of Farah Goes Bang Matt Kaplan (2006), producer of young adult films, To All the Boys franchise Meera Menon (2006), Indian-American director, Equity Lilly Burns (2009), television producer, co-founder of Jax Media and president of Imagine Entertainment Eli Bush (2009), film and theatre producer and winner of the Golden Globe Award in 2018 for Lady Bird Jason Fuchs (2009), actor and screenwriter, Pan, Ice Age: Continental Drift Jessica Kingdon (2009), Academy Award-nominated Chinese-American documentary director Nuotama Bodomo (2010), Ghanaian filmmaker and co-writer of sketch comedy Random Acts of Flyness on HBO Sabaah Folayan (2013), director of documentary Whose Streets?
Some stellate cells were present in the macula flava, but started to show some signs of degeneration. The stellate cells synthesized fewer extracellular matrix molecules, and the cytoplasmic processes were shown to be short and shrinking, suggesting a decreased activity. Those results confirm the hypothesis that phonation stimulates stellate cells into producing more extracellular matrix. Furthermore, using a specially designed bioreactor, Titze et al. showed that fibroblasts exposed to mechanical stimulation have differing levels of extracellular matrix production from fibroblasts that are not exposed to mechanical stimulation. The gene expression levels of extracellular matrix constituents such as fibronectin, MMP1, decorin, fibromodulin, hyaluronic acid synthase 2, and CD44 were altered. All those genes are involved in extracellular matrix remodeling, thus suggesting that mechanical forces applied to the tissue, alter the expression levels of extracellular matrix related genes, which in turn allow the cells present in the tissue to regulate the extracellular matrix constituent synthesis, thus affecting the tissue's composition, structure, and biomechanical properties. In the end, cell-surface receptors close the loop by giving feedback on the surrounding extracellular matrix to the cells, affecting also their gene expression level.
Sources: en.wikipedia.org
== Purpose == The purpose of the GxP quality guidelines is to ensure a product is safe and meets its intended use. GxP guides quality manufacture in regulated industries including food, drugs, medical devices, and cosmetics. The most central aspects of GxP are good documentation practices (GDP), which are expected to be "ALCOA":
== Australian and New Zealand Society for Mass Spectrometry == The major awards from the Australian and New Zealand Society for Mass Spectrometry (ANZSMS) are the ANZSMS Medal, Morrison Medal, Bowel Medal, Michael Guilhaus Research Award and ANZSMS Fellows.
== Side effects == Side effects of selenium disulfide shampoo for dandruff appear to be infrequent. A randomized controlled trial of 100 people who received selenium disulfide reported side effects of itching or burning sensation of the scalp (3 people), eruption near the hairline (1 person), psoriasis (1 person), lightening or bleaching of hair color (2 people), orange staining of the scalp (1 person), and a chemical taste while shampooing (1 person). Selenium disulfide can cause discoloration of nails and light hair and can alter the color of hair dyes. Several scattered case reports of orange to red–brown scalp discoloration with selenium sulfide shampoo exist. The discoloration resolved shortly following discontinuation of selenium disulfide shampoo and its removal could be facilitated by lightly swabbing with isopropyl alcohol. Selenium disulfide may also discolor metallic jewellery. Case reports of temporary diffuse hair loss with selenium disulfide shampoo exist as well. Excessive environmental or occupational exposure to selenium has also been associated with hair loss and other adverse effects. However, hair loss has not been reported with topical selenium disulfide in several large studies. Selenium disulfide should not be applied to damaged skin as there is a risk of systemic absorption and associated toxicity. Systemic symptoms may include tremors, weakness, lethargy, lower abdominal pain, and occasional vomiting. These symptoms usually resolve within 10 days following exposure.
Sources: en.wikipedia.org
==== Dopamine receptor agonists ==== Apomorphine (Apofin; CHF-1526) – non-selective dopamine receptor agonist and other actions [330] Apomorphine subcutaneous (APO-go; Apokinon; Apokyn; Apomine; Britaject; KW-6500; Li Ke Ji; Movapo; Onapgotm; SPN-830) – non-selective dopamine receptor agonist and other actions [331] Bromocriptine (Parlodel) – dopamine D2-like receptor agonist and other actions Cabergoline (Dostinex) – dopamine D2-like receptor agonist and other actions Dihydroergocryptine (DHEC; Almirid; Cripar) – dopamine D2-like receptor agonist and other actions Lisuride (Dopergin) – dopamine D2-like receptor agonist and other actions Pergolide (Permax) – dopamine D2-like receptor agonist and other actions Piribedil (Trivastal, Pronoran) – dopamine D2-like receptor agonist and other actions Pramipexole (BI-Sifrol; Daquiran; Mirapex; Mirapexin; Pexola; Sifrol; SND-919; SND-919Y) – dopamine D2, D3, and D4 receptor agonist [332] Ropinirole (Adartrel; Repreve; Requip) – dopamine D2, D3, and D4 receptor agonist [333] Ropinirole (Requip CR; Requip LP; Requip XL; Requip XR; SKF-101468A) – dopamine D2, D3, and D4 receptor agonist [334] Ropinirole transdermal (Haruropi Tape; HP-3000) – non-selective dopamine receptor agonist and other actions [335] Rotigotine transdermal (Leganto; N-0437; N-0923; Neupro; Neupro Patch; Nubrenza; SPM-962) – non-selective dopamine receptor agonist and other actions [336] Talipexole (BHT-920; Domin) – dopamine D2 receptor agonist and α2-adrenergic receptor agonist [337]
The thyroid hormones are created from thyroglobulin. This is a protein within the colloid in the follicular lumen that is originally created within the rough endoplasmic reticulum of follicular cells and then transported into the follicular lumen. Thyroglobulin contains 123 units of tyrosine, which reacts with iodine within the follicular lumen. Iodine is essential for the production of the thyroid hormones. Iodine (I0) travels in the blood as iodide (I−), which is taken up into the follicular cells by a sodium-iodide symporter. This is an ion channel on the cell membrane which in the same action transports two sodium ions and an iodide ion into the cell. Iodide then travels from within the cell into the lumen, through the action of pendrin, an iodide-chloride antiporter. In the follicular lumen, the iodide is then oxidized to iodine. This makes it more reactive, and the iodine is attached to the active tyrosine units in thyroglobulin by the enzyme thyroid peroxidase. This forms the precursors of thyroid hormones monoiodotyrosine (MIT), and diiodotyrosine (DIT). When the follicular cells are stimulated by thyroid-stimulating hormone, the follicular cells reabsorb thyroglobulin from the follicular lumen. The iodinated tyrosines are cleaved, forming the thyroid hormones T4, T3, DIT, MIT, and traces of reverse triiodothyronine. T3 and T4 are released into the blood. The hormones secreted from the gland are about 80–90% T4 and about 10–20% T3. Deiodinase enzymes in peripheral tissues remove the iodine from MIT and DIT and convert T4 to T3 and RT3.
Physicists were more accepting of Hahn's work, and he began attending a colloquium at the Physics Institute conducted by Heinrich Rubens. It was at one of these colloquia where, on 28 September 1907, he made the acquaintance of the Austrian physicist Lise Meitner. Almost the same age as himself, she was only the second woman to receive a doctorate from the University of Vienna, and had already published two papers on radioactivity. Rubens suggested her as a possible collaborator. So began the thirty-year collaboration and lifelong close friendship between the two scientists. In Montreal, Hahn had worked with physicists including at least one woman, Harriet Brooks, but it was difficult for Meitner at first. Women were not yet admitted to universities in Prussia. Meitner was allowed to work in the wood shop, which had its own external entrance, but could not enter the rest of the institute, including Hahn's laboratory space upstairs. If she wanted to go to the toilet, she had to use one at the restaurant down the street. The following year, women were admitted to universities, and Fischer lifted the restrictions and had women's toilets installed in the building.
Sources: en.wikipedia.org
Anti-doping and clinical laboratories commonly use liquid chromatography-tandem mass spectrometry. The method can identify GW501516 and its metabolites in urine or blood. Detection depends on sample timing and the amount present.
PPARδ is a nuclear receptor that regulates genes linked to fatty acid oxidation and energy metabolism. Activation can alter lipid handling and energy use in experimental models. The full range of effects in humans is still under study.
The solid compound is generally stable when kept cold, dry, and protected from light. Solutions may degrade faster, so laboratory protocols often specify fresh preparation or cold storage. Stability can depend on solvent, concentration, and container.
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.