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 2026-07-07. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
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.
Laboratory detection of GW501516 commonly uses liquid chromatography coupled with tandem mass spectrometry. The method can identify the parent compound or its metabolites in urine and blood after sample cleanup. Protein precipitation, solid-phase extraction, or enzymatic hydrolysis may precede analysis, depending on the matrix. Reference standards are required for accurate quantification and confirmation. Because the compound is not approved, testing often occurs in anti-doping, forensic, or research settings rather than routine clinical care. Results are reported with limits of detection and quantification.
| 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. |
Products sold as cardarine have been found to contain incorrect compounds, variable amounts, or no active ingredient at all. Independent testing is required to verify identity and purity. Common analytical approaches include high-performance liquid chromatography, mass spectrometry, and nuclear magnetic resonance for structural confirmation. These methods can distinguish GW501516 from related PPAR agonists and from unrelated steroids. For regulators and researchers, such verification is central to interpreting both biological results and adverse event reports.
Cardarine is prohibited in competitive sport under the World Anti-Doping Agency code, where it is classified as a metabolic modulator. It is not approved as a prescription medicine in the United States, European Union, or other major markets. Regulatory action has focused on its presence in sports and in products marketed as research chemicals. Because it has no accepted medical indication, supply is often unregulated. This status creates legal and safety uncertainties for anyone who encounters the substance.
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.
=== Prominent people with this condition === Danny DeVito, American actor, producer, and director Robert Reich, former United States Secretary of Labor under President Bill Clinton from 1993 to 1997 David Wetherill, British Paralympian table tennis athlete
== GBS colonization == GBS is a normal component of the intestinal and vaginal microbiota in some people; GBS is an asymptomatic (presenting no symptoms) colonizer of the gastrointestinal tract and vagina in up to 30% of otherwise healthy adults, including pregnant women. GBS colonization may be permanent, intermittent, or temporary. In different studies, the GBS vaginal colonization rate ranges from 0% to 36%, with most studies reporting colonization rates in sexually active women over 20%. It has been estimated that maternal GBS colonization worldwide is 18%, with regional variation from 11% to 35%. These variations in the reported prevalence of asymptomatic GBS colonization may be attributable to the detection methods used and differences in study populations.
== Guest characters == Fragrantian Erika (フラグラント星人 衛里香, Furanguranto Seijin Erika): The princess of a royal intergalactic family from Planet Fragrant. She is kidnapped by Kevakia, who attempts to ransom her for the rare-but-powerful Wellness Stone, but she is rescued by Ban and Hoji, who delete Kevakia. Erika is portrayed by Risa Yoshiki (吉木 りさ, Yoshiki Risa). Doltockian Mano Mark (ドルトック星人マノ・マーク, Dorutokku Seijin Mano Māku): A scientist from Planet Doltock who attempts to deal with Beildon under the alias of Iwaki (岩木), only to be arrested for abetting the Alienizer's crimes. His human form is portrayed by Minosuke (みのすけ). Juuzaian Braidy (ジューザ星人ブライディ, Jūza Seijin Buraidi): A mantis-themed alien from Planet Juuza whom Kersus framed for the murder of her sister Karmia and Agent Abrella enlarged to distract the Dekarangers, who discover the truth and arrest Braidy for causing property damage in his enlarged state. Braidy is voiced by Yūsuke Numata (沼田 祐介, Numata Yūsuke). Hikaru Hiwatari (日渡 氷狩, Hiwatari Hikaru): A young ESPer with the ability to teleport inanimate objects. Originally a street wanderer, he hated humans because they mistreated him due to his powers, and he wanted to leave the planet as soon as possible. An Alienizer named Dazgonelr uses this to manipulate Hikaru into helping him commit crimes, until Jasmine convinces Hikaru to trust her. Following Dazgonelr's deletion, Hikaru leaves Earth to join S.P.D.'s training academy.
On 14 September 2025, the Wall Street Journal reported the US and China have reached the "framework of a deal" for the US operations of TikTok to be sold to a consortium of investors in the US including close Trump ally Larry Ellison of Oracle. The deal was completed by 22 January 2026, with a consortium of investors—including Oracle, Silver Lake, MGX, and others including the personal investment entity for Michael Dell—owning more than 80% of the new venture. ByteDance retained 19.9% ownership. Under the deal, the app would remain the same, and the algorithm would be adjusted over time to favor American topics for those users.
Sources: en.wikipedia.org
== Mechanical properties == Hydrogels have been investigated for diverse applications. By modifying the polymer concentration of a hydrogel (or conversely, the water concentration), the Young's modulus, shear modulus, and storage modulus can vary from 10 Pa to 3 MPa, a range of about five orders of magnitude. A similar effect can be seen by altering the crosslinking concentration. This much variability of the mechanical stiffness is why hydrogels are so appealing for biomedical applications, where it is vital for implants to match the mechanical properties of the surrounding tissues. Characterizing the mechanical properties of hydrogels can be difficult especially due to the differences in mechanical behavior that hydrogels have in comparison to other traditional engineering materials. In addition to its rubber elasticity and viscoelasticity, hydrogels have an additional time dependent deformation mechanism which is dependent on fluid flow called poroelasticity. These properties are extremely important to consider while performing mechanical experiments. Some common mechanical testing experiments for hydrogels are tension, compression (confined or unconfined), indentation, shear rheometry or dynamic mechanical analysis. Hydrogels have two main regimes of mechanical properties: rubber elasticity and viscoelasticity:
The epidermis is the strong, superficial layer that serves as the first line of protection against the outer environment. The human epidermis is composed of stratified squamous epithelial cells, which further break down into four to five layers: the stratum corneum, stratum granulosum, stratum spinosum and stratum basale. Where the skin is thicker, such as in the palms and soles, there is an extra layer of skin between the stratum corneum and the stratum granulosum called the stratum lucidum. The epidermis is regenerated from the stem cells found in the basal layer that develop into the corneum. The epidermis itself is devoid of blood supply and draws its nutrition from its underlying dermis. Its main functions are protection, absorption of nutrients, and homeostasis. In structure, it consists of a keratinized stratified squamous epithelium; four types of cells: keratinocytes, melanocytes, Merkel cells, and Langerhans cells. The predominant cell keratinocyte, which produces keratin, a fibrous protein that aids in skin protection, is responsible for the formation of the epidermal water barrier by making and secreting lipids. The majority of the skin on the human body is keratinized, with the exception of the lining of mucous membranes, such as the inside of the mouth. Non-keratinized cells allow water to "stay" atop the structure. The protein keratin stiffens epidermal tissue to form fingernails. Nails grow from a thin area called the nail matrix at an average of 1 mm per week.
=== Toxicity === At present, the information needed to determine if HMX causes cancer is insufficient. Due to the lack of information, EPA has determined that HMX is not classifiable as to its human carcinogenicity. The available data on the effects on human health of exposure to HMX are limited. HMX causes CNS effects similar to those of RDX, but at considerably higher doses. In one study, volunteers submitted to patch testing, which produced skin irritation. Another study of a cohort of 93 workers at an ammunition plant found no hematological, hepatic, autoimmune, or renal diseases. However, the study did not quantify the levels of exposure to HMX. HMX exposure has been investigated in several studies on animals. Overall, the toxicity appears to be quite low. HMX is poorly absorbed by ingestion. When applied to the dermis, it induces mild skin irritation but not delayed contact sensitization. Various acute and subchronic neurobehavioral effects have been reported in rabbits and rodents, including ataxia, sedation, hyperkinesia, and convulsions. The chronic effects of HMX that have been documented through animal studies include decreased hemoglobin, increased serum alkaline phosphatase, and decreased albumin. Pathological changes were also observed in the animals' livers and kidneys. Gas exchange rate was used as an indicator of chemical stress in Northern bobwhite quail (Colinus virginianus) eggs, and no evidence of alterations in metabolic rates associated with HMX exposure was observed.
=== Zhejiang === In October 2002, Xi left Fujian and became the deputy governor, acting governor and deputy Party secretary of neighbouring Zhejiang. He eventually took over as provincial Party Committee secretary after the 16th Party National Congress, occupying a top provincial office for the first time in his career. In November 2002, he was elected a full member of the 16th Central Committee by the 16th Party National Congress, marking his ascension to the national stage. While in Zhejiang, Xi presided over reported growth rates averaging 14% per year. During this period, Zhejiang increasingly transitioned away from heavy industry. Xi's career in Zhejiang was marked by a tough and straightforward stance against corrupt officials. This earned him a name in the national media and drew the attention of China's top leaders. Between 2004 and 2007, Li Qiang acted as Xi's chief of staff through his position as secretary-general of the Zhejiang Party Committee, where they developed close mutual ties. During this period, Xi and Li drafted the Double Eight Strategy, which listed eight comparative advantages of Zhejiang and eight corresponding actions to improve the province.
=== Detection === A procedure of retrospective detection of Novichok type poisons in victim's tissues was proposed in 2021-2. This method is a modification of the procedure that was developed earlier for identification of sarin poisoning. This method capitalizes on the fact that poisoning by organic phosphonates occurs via phosphonylation of the hydroxy group of serine in the active site of cholinesterases, and that severe poisoning occurs when a major part of these enzymes are inactivated. The concentration of butyryl cholinesterase (HuBuChE) in human plasma is normally about 80 nM. That makes it a good source of adducts that can be subjected to analysis. The procedure consists of three steps (see the Figure A). First, HuBuChE is obtained from the victim's plasma. Second, the enzyme is subjected to pepsin proteolysis. Third, the peptide mixture obtained is subjected to LC-MSMS analysis. If no poisoning took place, the peptide mixture contains a non-modified nonapeptide FGESAGAAS. However, cholinesterases are inactivated due to a chemical reaction with Novichok type nerve agent, the modified nonapeptide is be detected, and its exact (high resolution) mass (along with the mass of the secondary ion produced during collision induced dissociation) allows unambiguous identification of the fact of poisoning and the exact structure of the poison. Thus, the example at Figure A shows the masses of the primary and secondary ions obtained from the plasma of the victim poisoned by A-230. If a victim is poisoned by other Novichok type agents, the masses are different.
Sources: en.wikipedia.org
The first investigation conducted in China was by the Wuhan Municipal Health Commission, responding to hospitals reporting cases of pneumonia of unknown etiology, resulting in the closure of the Huanan Seafood Wholesale Market on 1 January 2020 for sanitation and disinfection. The Chinese Center for Disease Control and Prevention (CCDC) entered the market the same day and took samples; as the animals had been removed before public-health authorities came in, no animals were sampled, although that would have been more conclusive. In April 2020, China imposed restrictions on publishing academic research on the novel coronavirus. Investigations into the origin of the virus would receive extra scrutiny and must be approved by Central Government officials. The restrictions do not ban research or publication, including with non-Chinese researchers; Ian Lipkin, a US scientist, has been working with a team of Chinese researchers under the auspices of the Chinese Center for Disease Control and Prevention, a Chinese government agency, to investigate the origin of the virus. Lipkin has long-standing relationships with Chinese officials, including premier Li Keqiang, because of his contributions to rapid testing for SARS in 2003. The Huanan live-animal market was suspected of being the source of the virus, as there was a major, early cluster of cases there. On 31 January 2021, a team of scientists led by the World Health Organization visited the market to investigate the origins of COVID-19.
=== Surface modification === The surface modification of nanocellulose is currently receiving a large amount of attention. Nanocellulose displays a high concentration of hydroxyl groups at the surface which can be reacted. However, hydrogen bonding strongly affects the reactivity of the surface hydroxyl groups. In addition, impurities at the surface of nanocellulose such as glucosidic and lignin fragments need to be removed before surface modification to obtain acceptable reproducibility between different batches.
=== Foundations of organic synthesis and the origin of life === Until the 19th century, there was considerable acceptance of the theory of spontaneous generation, the idea that "lower" animals, such as insects or rodents, arose from decaying matter. However, several experiments in the 19th century – particularly Louis Pasteur's swan neck flask experiment in 1859 — disproved the theory that life arose from decaying matter. Charles Darwin published On the Origin of Species that same year, describing the mechanism of biological evolution. While Darwin never publicly wrote about the first organism in his theory of evolution, in a letter to Joseph Dalton Hooker, he speculated:But if (and oh what a big if) we could conceive in some warm little pond with all sorts of ammonia and phosphoric salts, light, heat, electricity etcetera present, that a protein compound was chemically formed, ready to undergo still more complex changes [...]"
Rentrop did not generalize about the functional significance of these collaterals, which he said was "unknown," but their existence suggests that they may exert a preemptive, protective effect. Subsequently, Rentrop's associate Cohen prospectively evaluated 23 patients undergoing PTCA and observed that during balloon inflation, the mean grade of collateral filling increased dramatically. Nineteen of 23 patients showed improvement (p=0.01) but post-PTCA arteriography revealed no visible collaterals in any patient. The functional effect of filling was dramatic: using an index of ischemia (based on the percent of hypocontractile perimeter of myocardium, sum of ST segment elevation, and time of onset of angina), Cohen found that grade 0 or 1 filling confers only nominal protection from ischemia (i.e., filling is non-existent or of side branches only), but partial filling (i.e. grade 2 or greater) of these segments provides almost complete preservation of the affected myocardium from the asynergy associated with critical coronary stenosis. Pain was observed in all nine patients with 0 or 1 filling, but in only five of 14 patients with grade 2 or 3 filling. Thus, the severity of symptoms correlated inversely with the degree of observed collateral filling. In another often-cited study, Freedman focused on the issue of MI prevention by selecting 121 patients with severe single vessel disease. 64 had Q-wave infarction and 57 did not; 32 had unstable angina or subendocardial infarction.
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.
LC-MS/MS is common, often after sample cleanup. The assay targets GW501516 or its metabolites.