circadian rhythm 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 2025-08-04. Where a claim depends on a specific study, the study is described rather than over-claimed.
Research interest in SR9009 grew from studies showing improved running endurance in mice after short treatment periods. Those experiments linked the compound to increased mitochondrial content and fatty acid oxidation in muscle, but the findings come from animal models and specific dosing schedules. Independent replication has been limited, and the pathways connecting REV-ERB activation to exercise performance are still being mapped. Whether similar responses occur in humans is an open question.
SR9009 is often grouped with compounds studied for circadian and metabolic regulation rather than with classical anabolic steroids. Its interactions with nuclear receptors differ from those of androgen receptor ligands, and its proposed mechanisms involve transcriptional control rather than direct hormone signaling. Some sources classify it as a metabolic modulator because of observed effects on energy utilization. The distinction matters for regulation and for interpreting research results across different compound classes.
Regulatory treatment of SR9009 varies by country and context. It is not approved as a therapeutic drug by agencies such as the United States Food and Drug Administration or the European Medicines Agency. Sports authorities list it as a prohibited substance; the World Anti-Doping Agency classifies it among hormone and metabolic modulators. Legal status for personal possession or sale differs across jurisdictions, and some countries may restrict it under analog or research chemical laws. Buyers who seek verified material often rely on independent laboratory testing because online product labels may not match contents.
Laboratory samples of SR9009 are typically handled as research chemicals rather than pharmaceuticals. Suppliers usually state that the material is for research use only and not for human or veterinary administration. Storage recommendations generally call for a freezer at approximately −20 °C, protection from light, and a desiccated environment. The solid is often described as a white to off-white powder. Solubility is commonly reported in organic solvents such as dimethyl sulfoxide and ethanol, with low solubility in water.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C20H24ClN3O4S | Reported for the free base |
| Molecular weight | 437.9 g/mol | Calculated from the formula |
| Primary target | REV-ERBα and REV-ERBβ | Nuclear receptors involved in circadian regulation |
| Solubility | Soluble in DMSO and ethanol | Poorly soluble in water |
| Typical storage | -20 °C, desiccated | Protect from light and moisture |
Regulatory treatment of SR9009 varies by country and region. It is not approved as a pharmaceutical, and several jurisdictions restrict its sale for human consumption. Some authorities classify it as a research chemical, a prescription-only substance, or a prohibited performance-enhancing agent in sport. Purchasers may encounter certificates of analysis, but these documents do not guarantee identity, purity, or legality. In research settings, institutional safety reviews and controlled procurement help ensure that materials are handled under appropriate oversight. The absence of harmonized rules means that legal status can change and requires verification.
Analytical identification of SR9009 typically relies on liquid chromatography coupled with tandem mass spectrometry. In biological samples, researchers first separate the compound from matrix components using protein precipitation, liquid-liquid extraction, or solid-phase extraction. High-performance liquid chromatography with ultraviolet detection and nuclear magnetic resonance spectroscopy can support structural confirmation of reference materials. Because SR9009 is a small, relatively lipophilic molecule, reverse-phase columns and acidic mobile phases are common. Laboratories often include isotope-labeled internal standards to improve quantification and to correct for ion suppression.
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.
SR9009 is a synthetic small molecule studied as an agonist of the nuclear receptors REV-ERBα and REV-ERBβ. These receptors help regulate circadian rhythms and metabolic gene expression. In laboratory experiments, SR9009 binds these receptors and alters transcription of genes involved in lipid handling, glucose metabolism, and mitochondrial function. It is not a naturally occurring compound and has no approved therapeutic use. Research interest stems from its ability to modify energy metabolism in cells and animal models.
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.
Scientific discussion of SR9009 often separates animal evidence from human anecdote. Rodent studies provide controlled data on endurance, metabolism, and gene expression, but they use specific strains, doses, and treatment durations. Human reports are mostly uncontrolled and cannot establish cause and effect. Open questions include oral bioavailability, tissue distribution, metabolic stability, and long-term effects. Review articles generally call for more rigorous pharmacokinetic and safety research before any clinical use could be considered.
Analytical methods for SR9009 typically rely on liquid chromatography coupled with tandem mass spectrometry. The technique can separate the parent compound from related substances and detect low concentrations in biological matrices. Urine and blood are common samples in anti-doping testing, while in vitro studies may use cell culture media. Rapid metabolism and low expected concentrations make method validation important for reliable identification. Exact metabolite patterns can vary by species and are not fully mapped.
Regulatory treatment of SR9009 reflects its investigational status. The compound has no approved human therapeutic indication, and sports authorities prohibit its use. It appears on anti-doping lists as a non-approved substance or metabolic modulator, depending on the list version. Products sold online as research chemicals are not quality-controlled medicines, so their identity and purity can differ from the label. Such products may also contain unlisted compounds, which complicates both testing and safety assessment.
Bagwell, along with Craig Biggio were on hand to witness the Astros win their first-ever World Series championship at Dodger Stadium on November 1, 2017. Both were elated at their franchise's first championship with Bagwell saying, "I'm ecstatic. They're great kids, they play hard, they never gave up. To see them win, the celebration, excitement, relief...the city of Houston, I'm sure, is going crazy right now. I couldn't be more proud of the guys that represent the Houston Astros right now." Both Bagwell and Biggio received World Series rings from the Astros during the World Series ring ceremony before an April 3, 2018 game against the Baltimore Orioles.
William DeGrado (born 12 September 1955) is a professor at the University of California, San Francisco, where he is the Toby Herfindal Presidential Professor of Entrepreneurship and Innovation in the Department of Pharmaceutical Chemistry. As an early pioneer of protein design, he coined the term de novo protein design. He is also active in discovery of small molecule drugs for a variety of human diseases. He is a member of the U.S. National Academy of Sciences (1999), American Academy of Arts & Sciences (1997) and National Academy of Inventors. He also is a scientific cofounder of Pliant therapeutics.
=== World Cups === A study titled "Doping in Germany from 1950 to today", published in August 2013, stated that some members of the Germany national team received injections during their successful world cup 1954. Erik Eggers, who wrote about the preanabolic period in the study, was sure that the injections didn't contain vitamin C ("They could have just eaten an orange") but assumed that they contained Pervitin. It also stated that Pervitin (an upper, also used massively by soldiers in World War 2) was widespread in German football in the 1940s. The study, 800 pages in length and costing 450.000 Euro, was done by Berlin's Humboldt University and financed by the institute of sports science. Mohamed Kaci-Saïd, Djamel Menad, Tedj Bensaoula, Medi Cerbah, Mohamed Chaïb, Salah Larbès, Abdelkader Tlemçani, members of Algerias national side in the 1980s, claim that they were given performance-enhancing drugs. They suspect this to be the reason why they all fathered disabled children. Chaib, father of three disabled children, demanded the medical records and was told they didn't exist anymore. Rashid Hanafi, team doctor back then, also suspected there were suspicious practices going on. He told CNN that he was "not allowed to take a look at the medical records of the players any more when Rogov took over as coach in 1981". Alexander Tabartschuk, main doctor of the team, said he only handed vitamins. Algeria fell victim to the Disgrace of Gijón in 1982 and won the African Cup eight years later.
Gastric acid production is regulated by both the autonomic nervous system and several hormones. The parasympathetic nervous system, via the vagus nerve, and the hormone gastrin stimulate the parietal cell to produce gastric acid, both directly acting on parietal cells and indirectly, through the stimulation of the secretion of the hormone histamine from enterochromaffin-like cells (ECLs). Vasoactive intestinal peptide, cholecystokinin, and secretin all inhibit production. The production of gastric acid in the stomach is tightly regulated by positive regulators and negative feedback mechanisms. Four types of cells are involved in this process: parietal cells, G cells, D cells and enterochromaffin-like cells. Beside this, the endings of the vagus nerve (CN X) and the intramural nervous plexus in the digestive tract influence the secretion significantly. Nerve endings in the stomach secrete two stimulatory neurotransmitters: acetylcholine and gastrin-releasing peptide. Their action is both direct on parietal cells and mediated through the secretion of gastrin from G cells and histamine from enterochromaffin-like cells. Gastrin acts on parietal cells directly and indirectly too, by stimulating the release of histamine. The release of histamine is the most important positive regulation mechanism of the secretion of gastric acid in the stomach. Its release is stimulated by gastrin and acetylcholine and inhibited by somatostatin.
If the pressure at the outlet is lower than the pressure at the inlet and remains that way in spite of the pumping, then this pressure difference opens both check valves simultaneously and the liquid flows through the pump head uncontrollably from inlet to outlet. This can happen whether the pump is working or not. This situation can be avoided by placing a correctly rated positive pressure differential check valve downstream of the pump. Such a valve will only open if a minimum rated pressure differential across the valve is exceeded, something which most high-pressure metering pumps can easily exceed.
Sources: en.wikipedia.org
=== Breeding === The giant gourami is an egg layer and builds a nest from plant fibers. Both male and female gourami participates at building nests, though the male appears to play a more prominent role. The male and female are distinguished by the dorsal fins and body color. The dorsal fin on the male ends in a point, and the body is darker changing to nearly black during spawning. After building nest the eggs will be laid before next 24 hours. When breeding, the water in the tank should be decreased to about 20 cm (8 in) deep and the temperature should be 28 °C (82 °F). After spawning, the female is removed to a separate tank as the male will jealously guard the eggs, in a captive environment, sometimes becoming aggressive towards the female. The eggs hatch in 24 hours. They must be kept in a dark aquarium.
=== Medication === If monitoring reveals failing control of glucose levels with these measures, or if there is evidence of complications like excessive fetal growth, treatment with insulin might be necessary. This is most commonly fast-acting insulin given just before eating to blunt glucose rises after meals. Care needs to be taken to avoid low blood sugar levels due to excessive insulin. Insulin therapy can be normal or very tight; more injections can result in better control but require more effort, and there is no consensus that it has large benefits. A 2016 Cochrane review (updated in 2023) concluded that quality evidence is not yet available to determine the best blood sugar range for improving health for pregnant women with GDM and their babies. There is some evidence that certain medications by mouth might be safe in pregnancy, or at least, are less dangerous to the developing fetus than poorly controlled diabetes. When comparing which diabetes tablets (medication by mouth) work best and are safest, there is not enough quality research to support one medication over another. The medication metformin is better than glyburide. If blood glucose cannot be adequately controlled with a single agent, the combination of metformin and insulin may be better than insulin alone. Another review found good short term safety for both the mother and baby with metformin but unclear long term safety. People may prefer metformin by mouth to insulin injections. Treatment of polycystic ovarian syndrome with metformin during pregnancy has been noted to decrease GDM levels.
=== Drug discovery and bio-conjugation === Click chemistry has become a cornerstone in drug discovery and bioconjugation. Its ability to rapidly and selectively form stable covalent bonds has facilitated the development of targeted therapeutics and diagnostic agents. Recent studies have explored the use of click chemistry in creating multifunctional drug delivery systems, enhancing the specificity and efficacy of treatments. The simplicity of click chemistry has had significant impact in many themes, especially pharmaceutical development. Click chemistry been used in numerous drug studies to study their mechanism of action. Discoveries include that salinomycin localizes to lysosomes to initiate ferroptosis in cancer stem cells and that metformin derivatives accumulate in mitochondria to chelate copper(II), affecting metabolism and epigenetic changes downstream in inflammatory macrophages. In combination with combinatorial chemistry, high-throughput screening, and building chemical libraries, click chemistry has hastened new drug discoveries by making each reaction in a multistep synthesis fast, efficient, and predictable.
=== Structure-activity-relationship (SAR) === An important part of designing a compound, that is an ideal inhibitor to a certain target, is to understand the amino acid sequence of the target site for the compound to bind to. Modelling both prothrombin and FXa makes it possible to deduct the difference and identify the amino acids at each binding site. At the bottom of the S1 pocket on FXa the binding amino acid is Asp-189 which amidine moieties can bind to. After X-raying the binding site of FXa, it was revealed that the S1 pocket had a planar shape, meaning that a flat amidinoaryl group should bind to it without steric hindrance. Modern direct Xa inhibitors are L-shaped molecules whose ends fit perfectly in the S1 and S4 pockets. The long side of the L-shape has to conform to a highly-specific tunnel within the targets active site. To accomplish that, this part of the molecules is designed to have little formal interactions with FXa in that region. As there is no specific bonding, the fit of these agents between the pockets of FXa increases the total specificity of the drugs to the FXa molecule. The interaction between the S1 pocket of FXa and the inhibitor can be both ionic or non-ionic, which is important because it allows the design of the moiety to be adjusted to increase oral bioavailability. Previously designed compounds were charged molecules that are not absorbed well in the gastrointestinal tract and therefore did not reach high serum concentrations.
Noriega received several warnings about the invasion from individuals within his government; though he initially disbelieved them, they grew more frequent as the invasion drew near, eventually convincing Noriega to go on the run. Noriega used a number of subterfuges, including lookalikes and playbacks of his recorded voice, to confuse U.S. surveillance as to his whereabouts. During his flight, Noriega reportedly took shelter with several supportive politicians, including Balbina Herrera, the mayor of San Miguelito. The last two days of his flight were spent partly with his ally Jorge Krupnick, an arms dealer also wanted by the U.S. Kempe reported that Noriega considered seeking sanctuary in the Cuban or Nicaraguan embassies, but both buildings were surrounded by U.S. troops. On the fifth day of the invasion, Noriega and four others took sanctuary in the Apostolic Nunciature, the Holy See's embassy in Panama. Having threatened to flee to the countryside and lead guerrilla warfare if not given refuge, he instead turned over the majority of his weapons, and requested sanctuary from Archbishop José Sebastián Laboa, the papal nuncio. Prevented by treaty from invading the Holy See's embassy, U.S. soldiers from Delta Force and part of Operation Nifty Package erected a perimeter around the Nunciature. Attempts to dislodge Noriega from within included gunning vehicle engines, turning a nearby field into a landing pad for helicopters, and playing rock music at loud volumes (a Van Halen cassette tape was provided by Special Forces Sergeant John Bishop).
Sources: en.wikipedia.org
It is a synthetic REV-ERB agonist used mainly in preclinical research. It is not an approved medicine for human use.
It binds to REV-ERBα and REV-ERBβ, nuclear receptors involved in circadian and metabolic gene regulation. This can alter transcription of genes related to lipid and glucose metabolism in experimental models.
No controlled human trials have established that effect. Endurance findings come primarily from rodent studies, and human responses remain unknown.
Legality depends on the country and the intended use. In many places it is sold as a research chemical, but sports and medicine regulations restrict it.