Everything below concerns circadian rhythm. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Updated 2026-08-01. Numbers and descriptions here follow the published literature rather than marketing material.
Physicochemical behavior influences handling. SR9009 is described as a solid with limited aqueous solubility, so organic solvents such as dimethyl sulfoxide or ethanol are common in research stock solutions. Aqueous dilution can produce precipitates if the organic content is too low. Light, heat, and repeated freeze-thaw cycles may affect stability. Storage recommendations usually specify a desiccated freezer environment protected from light, but exact stability data depend on the formulation and matrix.
Detection in biological samples can be complicated by rapid metabolism and low circulating concentrations. Some studies report phase I and phase II metabolites, and analytical methods may need to target those species in addition to the parent compound. Immunoassays are not broadly available, so mass spectrometry remains the main confirmatory approach. For anti-doping testing, laboratories look for SR9009 and its metabolites using validated LC-MS methods. Open questions include how long metabolites remain detectable and how different routes of administration alter detection windows.
Regulatory status varies by country and intended use. Major drug agencies have not granted marketing authorization for SR9009 as a medicine, and it is not listed as a controlled substance in many jurisdictions. It is often sold as a research chemical, a category that may fall outside pharmaceutical manufacturing rules. Buyers should verify local laws and supplier documentation, including certificates of analysis. The lack of standardized quality controls raises concerns about identity, purity, and actual content in products marketed online.
In laboratory settings, SR9009 is commonly identified by its molecular structure and its interaction with REV-ERB receptors. Vendors may list it under synonyms such as Stenabolic or REV-ERB agonist, but those names do not define purity or identity. Analytical confirmation typically uses high-performance liquid chromatography with ultraviolet detection or liquid chromatography–mass spectrometry. A reference standard is needed to compare retention time and mass spectrum, because the compound can be confused with related research chemicals.
| Property | Value | Notes |
|---|---|---|
| Appearance | Off-white to pale yellow solid | Visual description varies with purity and source |
| Solubility | Soluble in DMSO and ethanol; poorly soluble in water | Organic stock solutions are common in research |
| Typical storage | -20 °C, desiccated, protected from light | Avoid repeated freeze-thaw cycles |
| Typical analytical method | LC-MS or HPLC-UV | Reference standards are needed for quantification |
| Molar mass | Approximately 437.9 g/mol | Calculated from the reported free-base formula |
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.
Most published work on SR9009 consists of preclinical studies. It is widely sold as a research chemical, a category that does not imply safety, efficacy, or pharmaceutical-grade quality. Sports anti-doping organizations have listed SR9009 as a prohibited substance, and its presence in an athlete sample can lead to sanctions. Legal status differs by country; in several jurisdictions it is not approved for human consumption and may be treated as an unapproved new drug.
SR9009 is a synthetic small molecule studied as an agonist of the nuclear receptors REV-ERBα and REV-ERBβ. It is not a steroid, peptide, or natural hormone. In scientific literature, it appears under the code SR9009 and in non-scientific contexts as Stenabolic. The compound was identified through chemical screening efforts aimed at targeting circadian clock components. Its status remains investigational, and no regulatory agency has approved it as a human medicine.
REV-ERB proteins help regulate daily cycles in gene expression, including genes tied to lipid and glucose metabolism. SR9009 binds these receptors and alters their activity in cell and animal experiments. Consequences observed in rodents include changes in skeletal muscle oxidative capacity, blood lipid levels, and exercise performance. The precise chain from receptor occupancy to whole-body effects is still an active area of study. Human responses cannot be assumed from rodent data.
Research interest in SR9009 grew from studies of circadian biology and metabolic disease. Preclinical reports describe effects on exercise capacity, muscle metabolism, and blood lipid levels in rodents, but these findings come from controlled laboratory settings. The compound has low oral bioavailability in animals, which limits systemic exposure after swallowing. Investigators often use injected routes in experiments to achieve measurable plasma concentrations. Human clinical data are sparse, no approved therapeutic product exists, and whether animal effects translate to humans remains an open question.
Regulatory and sporting contexts treat SR9009 as a prohibited substance in many elite competitions. Its presence on banned lists reflects concerns about performance enhancement and unknown long-term safety. Analytical chemists have developed methods to detect the parent compound and its metabolites in urine and blood. Literature discussions distinguish between in vitro potency, animal pharmacology, and anecdotal human reports. The latter are difficult to verify because products sold online may lack purity or contain different compounds.
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, lipid metabolism, and inflammatory gene expression. In cell and animal experiments, SR9009 alters transcription of clock-controlled genes and metabolic pathways. The compound is not a hormone and does not resemble classical steroid structures. Its activity depends on binding to the ligand-binding domain of REV-ERB, where it can modify corepressor recruitment.
=== GABA receptors === GABA is an inhibitory neurotransmitter that plays an important role in regulating dopamine and glutamate neurotransmission. It was found that people with bipolar disorder had lower GABA levels, which results in excitotoxicity and can cause apoptosis (cell loss). Lithium has been shown to increase the level of GABA in plasma and cerebral spinal fluid. Lithium counteracts these degrading processes by decreasing pro-apoptotic proteins and stimulating release of neuroprotective proteins. Lithium's regulation of both excitatory dopaminergic and glutamatergic systems through GABA may play a role in its mood-stabilizing effects.
== Biochemical context == Most are accompanied by α-ketoglutarate α-decarboxylation caused by dehydrogenation of hydroxyl carboxylic acids such as carbonyl carboxylic malic acid, isocitric acid, etc. Pyruvate is susceptible to oxidative decarboxylation to deliver the equivalent of the acetyl anion:
== Other notable isomers == Holmium's nuclear isomer 166m167Ho has a half-life of 1,133 years, which is nearly the longest half-life of any holmium radionuclide. Only 163Ho, with a half-life of 4,570 years, is more stable. Both the excitation energy of the former, and the decay energy of the latter, are less than 10 keV. 229m90Th is a remarkably low-lying metastable isomer, only 8.355733554021(8) eV above the ground state. This low energy produces light at a wavelength of 148.3821828827(15) nm, in the far ultraviolet instead of the typical gamma ray band. This allows for direct nuclear laser spectroscopy. Such ultra-precise spectroscopy, however, could not begin without a sufficiently precise initial estimate of the wavelength, something that was only achieved in 2024 after two decades (from 2003 to 2024) of effort. The energy is so low that the ionization state of the atom affects its half-life. Neutral 229m90Th decays by internal conversion with a half-life of 7±1 μs, but because the isomeric energy is less than thorium's second ionization energy of 11.5 eV, this channel is forbidden in thorium cations and 229m90Th+ decays by gamma emission with a half-life of 1740±50 s. This conveniently moderate lifetime allows the development of a nuclear clock of unprecedented accuracy.
It is an emerging, upper-middle income economy and newly industrialized country; Brazil has one of the 10 largest economies in the world in both nominal and PPP terms, the largest economy in Latin America and the Southern Hemisphere, and the largest share of wealth in South America. With a complex and highly diversified economy, Brazil is one of the world's major or primary exporters of various agricultural goods, mineral resources, and manufactured products. The country ranks thirteenth in the world by number of UNESCO World Heritage Sites. Brazil is a founding member of the United Nations, the G20, BRICS, G4, Mercosur, Organization of American States, Organization of Ibero-American States, and the Community of Portuguese Language Countries; it is also an observer state of the Arab League and a major non-NATO ally of the United States.
The lists of Merriam-Webster's Words of the Year (for each year) are ten-word lists published annually by the American dictionary-publishing company Merriam-Webster, Inc., which feature the ten words of the year from the English language. These word lists started in 2003 and have been published at the end of each year. At first, Merriam-Webster determined its contents by analyzing page hits and popular searches on its website. Since 2006, the list has been determined by an online poll and by suggestions from visitors to the website. The following is the list of words that became Merriam-Webster's Word of the Year since 2003:
Sources: en.wikipedia.org
Riboflavin, also known as vitamin B2, is a vitamin found in food and sold as a dietary supplement. It is essential to the formation of two major coenzymes, flavin mononucleotide and flavin adenine dinucleotide. These coenzymes are involved in energy metabolism, cellular respiration, and antibody production, as well as normal growth and development. The coenzymes are also required for the metabolism of niacin, vitamin B6, and folate. Riboflavin is prescribed to treat corneal thinning, and taken orally, may reduce the incidence of migraine headaches in adults. Riboflavin deficiency is rare and is usually accompanied by deficiencies of other vitamins and nutrients. It may be prevented or treated by oral supplements or by injections. As a water-soluble vitamin, any riboflavin consumed in excess of nutritional requirements is not stored; it is either not absorbed or is absorbed and quickly excreted in urine, causing the urine to have a bright yellow tint. Natural sources of riboflavin include meat, fish and fowl, eggs, dairy products, green vegetables, mushrooms, and almonds. Some countries require its addition to grains. In its purified, solid form, it is a water-soluble yellow-orange crystalline powder. In addition to its function as a vitamin, it is used as a food coloring agent. Biosynthesis takes place in bacteria, fungi and plants, but not animals. Industrial synthesis of riboflavin was initially achieved using a chemical process, but current commercial manufacturing relies on fermentation methods using strains of fungi and genetically modified bacteria.
BCAAs also inhibit uptake of tyrosine, a precursor of catecholamines such as dopamine and norepinephrine, potentially depressing catecholamine synthesis. Because both serotonin and catecholamines influence exercise capacity, their simultaneous reduction may explain the relatively neutral net effect of BCAA supplementation on performance. BCAA supplementation also alters nitrogen metabolism. During exercise, serum ammonia levels increase, contributing to both muscular and central fatigue. In muscle, high ammonia enhances phosphofructokinase (PFK) activity, further increasing lactic acid production. BCAAs enhance glutamine synthesis, which consumes ammonia and limits its accumulation. Excess ammonia in the brain reduces levels of GABA and glutamate, promoting central fatigue. Finally, BCAA supplementation has been associated with reduced levels of creatine kinase in muscle following exercise, an indicator of reduced muscle damage. Creatine kinase transfers phosphate groups from ATP to form phosphocreatine, which buffers cellular energy supply. Meta-analyses suggest BCAA supplementation may lower creatine kinase levels and attenuate DOMS.
Sprigg urged Letsie I to negotiate Masopha's unconditional surrender, until a force of Cape Mounted Riflemen (CMR) could arrive to assist him. Letsie I replied that this was unrealistic, as most of the Basuto, including his sons, had rallied behind Masopha. Letsie and his armed retinue, returned to their village on 19 August after several days of negotiations, fearing that they would be ambushed if they remained outside Thaba Bosiu any longer. In a last ditch effort to prevent an uprising, Sprigg visited Letsie I in person. Letsie I then held another pitso—under Sprigg's new terms the rebel chiefs were to appear in court where they would receive a token fine, pledge to compensate those whose property they had seized, and comply with the gun regulations. Masopha remained defiant and held an assembly of his own, where he and Lerotholi began to prepare for war. Masopha believed that the Cape's troops had proved themselves to be incompetent during the suppression of Moorosi's revolt. He was further encouraged by rumors that the British would refuse to reinforce the Cape, and by the British defeat at the Battle of Isandlwana a year prior.
== Interactions == Iodine-131, a radioactive isotope used for thyroid imaging (scintigraphy) and therapy of thyroid cancers, can be less effective when used within two to six weeks after application of ioxaglic acid because of residual iodine in the body.
== History and research == Research in the early 1960s showed that in rats, administration of α-MSH caused sexual arousal, and work on this continued in many labs up through the 1980s, when scientists at the University of Arizona began attempting to develop α-MSH and analogs as potential sunless tanning agents, and synthesized and tested several analogs, including melanotan-I and melanotan II. Early in the research process one of the scientists, who was conducting experiments on himself with an early tool compound, melanotan II, injected himself with twice the dose he intended to and got an eight-hour erection, along with nausea and vomiting. As a tanning agent, melanotan I (now known as afamelanotide) was licensed by Competitive Technologies, a technology transfer company operating on behalf of the University of Arizona, to an Australian startup called Epitan, which changed its name to Clinuvel in 2006. Afamelanotide was approved by the FDA in 2019. As a sexual dysfunction agent, melanotan II was licensed by Competitive Technologies to Palatin Technologies. Palatin ceased development of melanotan II in 2000 and synthesized, patented, and began to develop bremelanotide, a likely metabolite of melanotan II that differs in that it has a carboxy group where melanotan II has an amide. Competitive Technologies (Clinuvel) sued Palatin for breach of contract and tried to claim ownership of bremelanotide; the parties settled in 2008 with Palatin retaining rights to bremelanotide, returning rights to melanotan II to Competitive Technologies, and paying US$800,000.
Sources: en.wikipedia.org
It is usually detected by LC-MS or HPLC-UV against a reference standard. In biological matrices, metabolite targeting can improve detection. No universal immunoassay is widely available.
The compound is generally handled as light-sensitive and stored cold and dry. Stability in solution depends on solvent, concentration, and storage time. Specific degradation rates are not fully standardized.
Limited water solubility affects formulation for cell and animal studies. Organic co-solvents are often used to dissolve it. Precipitation can confound assay results if not controlled.
Liquid chromatography–mass spectrometry is common for identity and purity checks. High-performance liquid chromatography with ultraviolet detection can also be used. Both methods require a suitable reference standard.