NR1D1 raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
Reviewed 2025-08-15. Anything still debated is marked as such rather than presented as settled.
SR9009 is a synthetic small molecule developed as an agonist of the nuclear receptors REV-ERBα (NR1D1) and REV-ERBβ (NR1D2). These receptors help regulate circadian rhythms and metabolic gene expression. In cell and animal studies, SR9009 alters transcription of genes involved in lipid metabolism, inflammation, and mitochondrial function. It is not an approved medicine, and its pharmacological profile in humans remains largely uncharacterized. The compound is frequently discussed in the context of circadian biology and metabolic research rather than clinical use.
Preclinical reports have linked SR9009 to improved endurance and altered energy expenditure in rodents. Such findings have prompted interest in whether REV-ERB activation can influence skeletal muscle metabolism. However, the reported effects depend on dose, route, and experimental model, and replication across laboratories is limited. Human trials have not established comparable outcomes, so claims about exercise performance remain speculative. The absence of controlled human data is a central limitation in interpreting these observations.
SR9009 is a synthetic small molecule studied as a REV-ERB agonist. REV-ERBα and REV-ERBβ are nuclear receptors that help regulate circadian rhythms and metabolic gene expression. The compound was identified in academic screening efforts to find synthetic ligands for these receptors. In cell and animal studies, SR9009 alters transcription of genes involved in lipid and glucose metabolism, and it can shift circadian behavior. It is not an approved therapeutic agent.
Mechanistically, SR9009 binds the ligand-binding domain of REV-ERBα/β and enhances recruitment of corepressor complexes. This represses target genes rather than activating them. Because REV-ERB proteins normally compete with ROR proteins at shared response elements, the net effect depends on tissue and timing. Researchers use SR9009 to probe how nuclear receptor signaling links the clock to metabolism, inflammation, and muscle biology. Findings are largely preclinical, and the precise contribution of each receptor subtype remains under study.
SR9009 is frequently discussed in fitness and research-chemical contexts, yet it has no approved medical indication. Regulatory agencies have not authorized it for human use, and it is not a standard prescription drug. Some sports organizations list it as a prohibited substance because of its potential performance-enhancing properties. Published human data are sparse, so claims about its effects in people often rely on animal models or anecdotal reports. Quality and identity of online materials can vary widely.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic REV-ERB agonist | Small molecule; not a steroid or peptide. |
| Primary targets | NR1D1 and NR1D2 | Also known as REV-ERBα and REV-ERBβ. |
| Studied routes | Intraperitoneal in rodents | Oral bioavailability in humans is not established. |
| Human approval | No approved therapeutic indication | No recognized clinical use. |
| Key uncertainty | Human physiological effects | Preclinical findings may not translate. |
In rodent studies, SR9009 has been reported to increase mitochondrial content in skeletal muscle and improve exercise endurance under some conditions. These findings led to popular descriptions such as an exercise mimetic, although that term oversimplifies the biology. Effects vary by dose, timing, tissue, and model. The compound's influence on circadian pathways means that time of administration can matter in experiments. Whether similar metabolic changes occur in humans remains largely unexplored in controlled published trials.
Pharmacokinetic data for SR9009 are limited in published literature. Some reports indicate low oral bioavailability and rapid clearance in animals, which complicates interpretation of exposure and effect. Researchers often use injected routes in preclinical work to achieve measurable systemic levels. Analytical studies rely on mass spectrometry to detect the parent compound and its metabolites. Questions about tissue distribution, active metabolites, and long-term consequences remain open. Species differences in metabolism can affect observed half-life and target engagement.
Preclinical reports describe effects on exercise endurance, mitochondrial content, and lipid profiles in rodents, but these findings come from specific experimental conditions. Many studies use high doses or delivery methods that may not translate directly to human use. SR9009 has been reported to have low oral bioavailability and a short half-life, which complicates interpretation of oral dosing studies. It is not established as safe or effective for any indication. Literature discussions often separate its pharmacological mechanism from unverified claims made in fitness and supplement markets.
SR9009 is a synthetic small molecule studied as an agonist of the nuclear receptors REV-ERBα and REV-ERBβ. It is not an approved medicine and has no established human therapeutic use. The compound appears in scientific literature as a tool for probing circadian and metabolic regulation. Online sellers often label it as a research chemical, sometimes using the nickname Stenabolic. Its chemical identity is distinct from selective androgen receptor modulators, stimulants, and peroxisome proliferator-activated receptor delta agonists. Researchers use it mainly in cell and animal experiments.
At the molecular level, SR9009 binds REV-ERBα and REV-ERBβ and alters their repressive activity on target genes. These nuclear receptors help regulate the circadian clock, lipid synthesis, glucose metabolism, and inflammatory pathways. By changing transcription, the compound can shift the timing or magnitude of downstream metabolic processes in model systems. It does not act through androgen receptors or adenosine receptors, which distinguishes it from several substances sold for athletic performance. Whether the same transcriptional changes occur in humans at tolerable exposures remains an open question because controlled human studies are lacking.
SR9009 binds REV-ERB receptors and alters their repressive activity on target genes. This action can change transcription of genes involved in lipid handling, glucose metabolism, and mitochondrial function. In rodent studies, treated animals have shown changes in muscle oxidative capacity and exercise performance, though effects vary by dose, duration, and model. The precise molecular steps connecting receptor binding to whole-body outcomes are still an active area of investigation. Findings in animals do not automatically translate to humans.
Because REV-ERB receptors are core clock components, SR9009 has been examined for effects on daily rhythms as well as metabolism. Research has explored whether the compound can shift or reinforce circadian gene expression in tissues such as liver and muscle. Some studies report improved metabolic markers in obese or diabetic mice, while others show context-dependent responses. Questions remain about which effects are direct, which are secondary to timing, and how they might differ across species.
Laboratory samples of SR9009 are typically supplied as a white to off-white powder. The compound dissolves readily in organic solvents such as dimethyl sulfoxide and ethanol, while its solubility in water is low. Because of this solubility profile, researchers often prepare concentrated stock solutions in an organic solvent before diluting them into aqueous assay buffers. Light exposure, moisture, and repeated freeze-thaw cycles can degrade many small molecules, so handling procedures usually aim to minimize these factors. Purity is commonly checked before use.
Storage conditions for research-grade SR9009 generally involve a freezer at approximately minus twenty degrees Celsius, sometimes lower for long-term preservation. Containers should remain tightly closed and protected from light. Desiccants may be used to limit moisture uptake. Solutions are often stored in aliquots to avoid repeated warming and cooling. Stability data for the compound under various conditions are limited, so laboratories typically follow supplier recommendations and verify performance through periodic analytical checks rather than assuming indefinite stability.
==== South Ossetian attacks and Georgian response ==== The commission said that a government "is generally not prevented" to use armed force against opposing side in internal conflicts, such as rebels or violent secessionists. However, the report said that Georgia had a non-use of force commitment under the international legal documents, such as the 1992 Sochi Agreement and 1996 Memorandum on Measures to Provide Security and Strengthen Mutual Trust between the Sides in the Georgian-South Ossetian Conflict. The commission said that the South Ossetian attacks on Georgian villages (Zemo Nikozi, Kvemo Nikozi, Avnevi, Nuli, Ergneti, Eredvi and Zemo Prisi) equaled to an "attack by the armed forces of a State on the territory of another State" similar to the situations described in Art. 3(a) of UN Resolution 3314. Since the South Ossetian attacks mainly targeted Georgian peacekeepers and Georgian police, this was "an attack by the armed forces of South Ossetia on the land forces of Georgia". The commission found out that several residents of the assaulted villages became casualties in "the acts preceding the outbreak of the hostilities" and "From 6 August on, continuous heavy fighting took place." The commission could not prove that Russian peacekeepers took part in the attacks on Georgian villages, but noted that "Such attacks were rather initiated by the South Ossetian militia." The commission also said "South Ossetia violated the prohibition of the use of force" as long as South Ossetia had attacked the Georgian villages.
=== Doping === PRP treatments may violate anti-doping rules. As of 2010, it was not clear whether PRP could have a systemic impact on circulating cytokine levels, affecting doping tests and whether PRP treatments had systemic anabolic effects or affect performance. In January 2011, the World Anti-Doping Agency removed intramuscular injections of PRP from its prohibitions after determining that there is a "lack of any current evidence concerning the use of these methods for purposes of performance enhancement".
Campylobacter jejuni which can lead to secondary Guillain–Barré syndrome and periodontitis Clostridium perfringens, the "cafeteria germ" Salmonella spp. – its S. typhimurium infection is caused by consumption of eggs or poultry that are not adequately cooked or by other interactive human-animal pathogens Escherichia coli O157:H7 enterohemorrhagic (EHEC) which can cause hemolytic-uremic syndrome Other common bacterial foodborne pathogens are:
Sources: en.wikipedia.org
Amides are pervasive in nature and technology. Proteins and important plastics like nylons, aramids, Twaron, and Kevlar are polymers whose units are connected by amide groups (polyamides); these linkages are easily formed, confer structural rigidity, and resist hydrolysis. Amides include many other important biological compounds, as well as many drugs like paracetamol, penicillin and LSD. Low-molecular-weight amides, such as dimethylformamide, are common solvents.
Pharmacokinetic analysis has largely taken place in live rodents as well as in rodent and human microsomes. Owing to the heterogeneity of analysis and paucity of human experiments conducted thus far, the pharmacokinetic profile of mitragynine is not complete. However, initial pharmacokinetic studies in humans have yielded preliminary information. In a study of 10 healthy volunteers taking orally administered mitragynine from whole leaf preparations, mitragynine appeared to have a much longer half-life than typical opioid agonists (7–39 hours) and reached peak plasma concentration (Tmax) within 1 hour of administration. However, another study involving a Kratom tea preparation reported a much shorter half-life of 3 hours. Mitragynine is estimated to have a bioavailability of 21%.
After the Qatari Ministry of Defence announced on 2 March that two Iranian drones attacked Qatari gas facilities, followed closely by an announcement from QatarEnergy that all gas production in the country had been halted, European natural gas prices nearly doubled. This raised concerns over energy security and fertiliser costs. EU natural gas prices decreased again to a less-high €48/MWh on Wednesday 4 March. The Iran conflict also bolstered the necessity for renewable energy, as solar and wind power can reduce vulnerability to external supply and decentralised power generation that offers greater autonomy from global energy markets. With fluctuating oil prices, renewable energy has become significantly more cost-competitive. April 2026 was the strongest month of electric vehicle sales on record in Europe. Shell plc's CEO warned that Europe could face shortages of fuel by April. British supermarket chain Asda warned that it was already facing shortages of fuel at their fuel stations. In addition to broader fuel supply disruptions, reports in April 2026 indicated significant impacts on global energy and aviation markets linked to tensions in the Strait of Hormuz during the Iran–United States conflict. Restricted maritime traffic was reported to have contributed to supply constraints in oil and jet fuel, affecting global energy flows and increasing market volatility. The disruption contributed to sharp increases in global energy prices.
== Oxford == Oxford University Press, which publishes the Oxford English Dictionary and many other dictionaries, announces an Oxford Dictionaries UK Word of the Year and an Oxford Dictionaries US Word of the Year; sometimes these are the same word and simply dubbed Word of the Year. The word need not have been coined within the year or twelve months but it does need to have become prominent or notable during that time. There is no guarantee that the Word of the Year will be included in any Oxford dictionary if it's not present. The Oxford Dictionaries Words of the Year are selected by editorial staff from each of the Oxford dictionaries. The selection team is made up of lexicographers and consultants to the dictionary team, and editorial, marketing, and publicity staff.
Sources: en.wikipedia.org
Specifically, the complex of TAP, tapasin, MHS Class 1, ERp57, and calreticulin is called the peptide-loading complex (PLC). Peptides are loaded to MHC-I peptide binding groove between two alpha helices at the bottom of the α1 and α2 domains of the MHC class I molecule. After releasing from tapasin, peptide-MHC-I complexes (pMHC-I) exit the ER and are transported to the cell surface by exocytic vesicles. Naïve anti-viral T cells (CD8+) cannot directly eliminate transformed or infected cells. They have to be activated by the pMHC-I complexes of antigen-presenting cells (APCs). Here, antigen can be presented directly (as described above) or indirectly (cross-presentation) from virus-infected and non-infected cells. After the interaction between pMHC-I and TCR, in presence of co-stimulatory signals and/or cytokines, T cells are activated, migrate to the peripheral tissues and kill the target cells (infected or damaged cells) by inducing cytotoxicity. Cross-presentation is a special case in which MHC-I molecules are able to present extracellular antigens, usually displayed only by MHC-II molecules. This ability appears in several APCs, mainly plasmacytoid dendritic cells in tissues that stimulate CD8+ T cells directly. This process is essential when APCs are not directly infected, triggering local antiviral and anti-tumor immune responses immediately without trafficking the APCs in the local lymph nodes.
The lamina propria is a thin layer of connective tissue that forms part of the moist linings known as mucous membranes or mucosae, which line various tubes in the body, such as the respiratory tract, the gastrointestinal tract, and the urogenital tract. The lamina propria is a thin layer of loose (areolar) connective tissue, which lies beneath the epithelium, and together with the epithelium and basement membrane constitutes the mucosa. As its Latin name indicates, it is a characteristic component of the mucosa, or the mucosa's "own special layer." Thus, the term mucosa or mucous membrane refers to the combination of the epithelium and the lamina propria. The connective tissue of the lamina propria is loose and rich in cells. The cells of the lamina propria are variable and can include fibroblasts, lymphocytes, plasma cells, macrophages, eosinophilic leukocytes, and mast cells. It provides support and nutrition to the epithelium, as well as the means to bind to the underlying tissue. Irregularities in the connective tissue surface, such as papillae found in the tongue, increase the area of contact of the lamina propria and the epithelium.
A substance can often be classified as an acid or a base. There are several different theories which explain acid–base behavior. The simplest is Arrhenius theory, which states that an acid is a substance that produces hydronium ions when it is dissolved in water, and a base is one that produces hydroxide ions when dissolved in water. According to Brønsted–Lowry acid–base theory, acids are substances that donate a positive hydrogen ion to another substance in a chemical reaction; by extension, a base is the substance which receives that hydrogen ion. A third common theory is Lewis acid–base theory, which is based on the formation of new chemical bonds. Lewis theory explains that an acid is a substance which is capable of accepting a pair of electrons from another substance during the process of bond formation, while a base is a substance which can provide a pair of electrons to form a new bond. There are several other ways in which a substance may be classified as an acid or a base, as is evident in the history of this concept. Acid strength is commonly measured by two methods. One measurement, based on the Arrhenius definition of acidity, is pH, which is a measurement of the hydronium ion concentration in a solution, as expressed on a negative logarithmic scale. Thus, solutions that have a low pH have a high hydronium ion concentration and can be said to be more acidic.
==== Africa ==== During Xi's administration, China has maintained cordial relationships with each Africa government except Eswatini, which recognizes Taiwan but not the PRC. Under Xi, China has cut back lending to Africa after fears that African countries could not repay their debts to China. Xi has also promised that China would write off debts of some African countries. In 2025, China announced that it would remove nearly all import tariffs on African countries.
Previously, there had been no detailed descriptions of their spectral properties in peer-reviewed general scientific literature. A small amount of agent A-230 was also claimed to have been synthesised in the Czech Republic in 2017 for the purpose of obtaining analytical data to help defend against these novel toxic compounds. The Soviet Union and Russia reportedly developed extremely potent fourth-generation chemical weapons from the 1970s until the early 1990s, according to a publication by two chemists, Lev Fyodorov and Vil Mirzayanov, in Moskovskiye Novosti weekly in 1992. The publication appeared just on the eve of Russia's signing of the Chemical Weapons Convention. According to Mirzayanov, the Russian Military Chemical Complex (MCC) was using defence conversion money received from the West for development of a chemical warfare facility. Mirzayanov made his disclosure out of environmental concerns. He was the head of a counter-intelligence department and performed measurements outside the chemical weapons facilities to make sure that foreign spies could not detect any traces of production. To his horror, the levels of deadly substances were eighty times greater than the maximum safe concentration. The Prosecutor-General of Russia effectively admitted the existence of Novichok agents when he brought a treason case against Mirzayanov. According to expert witness testimonies that three scientists prepared for the KGB, Novichok and other related chemical agents had indeed been produced and therefore Mirzayanov's disclosure represented high treason.
Sources: en.wikipedia.org
It is a synthetic compound that acts as an agonist at REV-ERBα and REV-ERBβ. It is used mainly as a research chemical to study circadian and metabolic pathways. It is not approved for human therapeutic use.
REV-ERB receptors generally repress transcription when bound by natural heme. SR9009 is described as an agonist that enhances this repressive activity. The result is altered expression of clock and metabolic genes.
Published controlled human trials are lacking. Some sources cite limited or unofficial reports, but these do not establish safety or efficacy. Claims about human performance effects remain unverified.
SR9009 is a synthetic compound investigated as an agonist of the nuclear receptors REV-ERBα and REV-ERBβ. It is used in preclinical research on circadian rhythm and metabolism. It is not an approved drug.