circadian clock raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
This page was last updated on 2025-10-30 and is reviewed periodically as new material appears.
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.
SR9009 is a synthetic small molecule developed as a REV-ERB agonist. It binds to REV-ERBα and REV-ERBβ, nuclear receptors that help regulate circadian rhythms and metabolic gene expression. In cell and animal studies, the compound alters lipid and glucose handling and influences skeletal muscle oxidative capacity. Its exact effects in humans remain largely uncharacterized because controlled clinical trials have not been reported. The molecule is frequently described in preclinical literature as a metabolic modulator.
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.
In laboratory settings, SR9009 is typically characterized by liquid chromatography–mass spectrometry (LC-MS) or high-performance liquid chromatography with ultraviolet detection (HPLC-UV). These methods can confirm identity and estimate purity, but they require reference standards for accurate quantification. Because SR9009 is not a licensed pharmaceutical, no harmonized pharmacopeial monograph exists. Laboratories often validate in-house methods for matrices such as plasma, urine, or cell culture media. Sample preparation may involve protein precipitation or liquid-liquid extraction before analysis.
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.
| 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 |
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.
Storage recommendations for SR9009 reference material typically specify a freezer at -20 °C or lower, with protection from moisture and light. Repeated freeze-thaw cycles can degrade small molecules and introduce variability. Stock solutions in dimethyl sulfoxide are often aliquoted to avoid repeated handling. Stability studies may examine degradation under heat, humidity, and light exposure. The compound's thiophene and nitro groups can participate in reactions that alter analytical signals over time, so such changes affect quantitative results.
Quality control for research materials includes identity confirmation by nuclear magnetic resonance and purity assessment by high-performance liquid chromatography. Mass spectrometry provides molecular weight confirmation and can detect related impurities. Purchasers should request a certificate of analysis that lists lot-specific data. Online products advertised for human use often lack such documentation. Distinguishing legitimate research material from mislabeled or contaminated samples is a recurring challenge in independent testing, and independent laboratories may use orthogonal methods to verify identity.
Detection of SR9009 in biological samples usually relies on liquid chromatography coupled to tandem mass spectrometry. This approach separates the compound from matrix components and identifies it by mass transitions. Because SR9009 can undergo metabolism, laboratories often look for both parent drug and specific metabolites. Sample preparation may involve protein precipitation or solid-phase extraction. Method validation examines sensitivity, carryover, and interference from related substances, and reference standards are required for accurate calibration.
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.
At low concentrations of TNP-ATP (≤1 μM), fluorescent intensity is proportional to the concentration of TNP added. However, at concentrations exceeding 1 μM, inner filter effects cause this relationship to no longer be linear. To correct this, researchers must determine the ratio of the predicted theoretical fluorescence intensity (assuming linearity) to the observed fluorescence intensity and then apply this correction factor. However, in most cases, researchers will try to keep the concentration of TNP to lower than 1 μM. To determine binding affinities, TNP-ATP is added to a solution and then titrated with protein. This produces a saturation curve from which the binding affinity can be determined. The number of binding sites may also be determined through this saturation curve by looking to see if there are sudden changes in slope. One can also titrate a fixed amount of protein with increasing additions of TNP-ATP to obtain a saturation curve. To do so, however, may get complicated due to the inner filter effects that will need to be corrected for. To determine dissociation constants, TNP-ATP can be competed off of a protein with ATP. The value of the dissociation constant Kd for a single-site binding can then be obtained by applying the Langmuir equation for a curve fit:
Health Canada followed with similar label updates in 2021, and Australia's Therapeutic Goods Administration aligned all SSRI and SNRI product information in 2024, noting that venlafaxine already carried a warning about persistent sexual dysfunction.
== History == Pentamidine was first used to treat African trypanosomiasis in 1937 and leishmaniasis in 1940 before it was registered as pentamidine mesylate in 1950. The sudden increase in requests for use of pentamidine isethionate in then unlicensed form from the CDC in the early 1980s for treating Pneumocystis jirovecii in young male patients was key in identifying the emergence of the HIV/AIDS epidemic at that time. Its efficacy against Pneumocystis jirovecii was demonstrated in 1987, following its re-emergence on the drug market in 1984 in the current isethionate form.
Kōji (Japanese: 麹; rōmaji: kōji, also written as the kokuji 糀) is a filamentous fungus, most commonly Aspergillus oryzae, which is traditionally used in Japanese cuisine for the fermentation of food, or a mixture of such a culture with wheat and soybean meal. The latter can be fried and eaten directly or processed to a sauce. The term kōji in English refers specifically to the Japanese types of starter cultures. The same Chinese character (Chinese: 麹; pinyin: qū, more commonly written as the homophonic 曲 in simplified Chinese texts) is used in Chinese to refer to Chinese starter cultures; see jiuqu. In Japanese, the genus Aspergillus is known with the common name of kōji mold (麹黴（コウジカビ）, kōji kabi), though the term is not fully limited to the genus (for example, Monascus purpureus is called 紅麹黴 "red kōji mold").
=== Treatment by medical professionals === In a healthcare setting, treatment depends on the severity of symptoms and intravenous access. If a patient is conscious and able to swallow safely, food or drink may be administered, as well as glucose tabs or gel. In those with intravenous access, 25 grams of 50% dextrose is commonly administered. When there is no intravenous access, intramuscular or intra-nasal glucagon may be administered.
Sources: en.wikipedia.org
The 2013 AFL season was the 117th season of the Australian Football League (AFL), the highest level senior Australian rules football competition in Australia, which was known as the Victorian Football League until 1989. The season featured eighteen clubs, ran from 22 March until 28 September, and comprised a 22-game home-and-away season followed by a finals series featuring the top eight clubs. The premiership was won by the Hawthorn Football Club for the eleventh time, after it defeated Fremantle by 15 points in the 2013 AFL Grand Final. The season was marred by a series of off-field controversies, with three clubs penalised in 2013 for separate infractions which had taken place over previous years: Essendon, following an Australian Sports Anti-Doping Authority investigation into the club's supplements program; Adelaide, after illegal payments and draft-tampering charges relating to Kurt Tippett's 2009 contract extension; and Melbourne, after an investigation into allegations that the club had intentionally lost matches towards the end of the 2009 season.
In either case, a mixture of unbound ligands, proteins, ligand-protein complexes is passed through a column of porous beads. Ligand-protein complexes are excluded from entering the beads and exit the column quickly, while unbound ligands must travel through the beads and are retained by the column for a longer time. Ligands that elute from the column early on are therefore inferred to be bound to a protein. The automated ligand identification system (ALIS), developed by Schering-Plough, uses a combined HPLC-based SEC to liquid chromatography-mass spectrometry (LC-MS) system that separates ligand-protein complexes from unbound ligands using SEC and diverts the complex toward an LC-MS system for on-line analysis of bound ligands. Novartis' SpeedScreen uses SEC in 96-well spin column format, also known as gel filtration chromatography, which allows for simultaneous removal of unbound ligands from up to 96 samples. Samples are also passed through porous beads, but centrifugation is used to move the sample through the column. SpeedScreen is not coupled to an LC-MS system and requires further processing prior to final analysis. In this case, ligands must be freed from their targets and analyzed separately.
=== Reinke's edema === A voice pathology called Reinke's edema, swelling due to abnormal accumulation of fluid, occurs in the superficial lamina propria or Reinke's space. This causes the vocal fold mucosa to appear floppy with excessive movement of the cover that has been described as looking like a loose sock. The greater mass of the vocal folds due to increased fluid lowers the fundamental frequency during phonation.
=== Mitral stenosis === Mitral stenosis is caused almost exclusively by rheumatic heart disease, and has a prevalence of about 0.1% in the United States. Mitral stenosis is the most common valvular heart disease in pregnancy.
TCEP (tris(2-carboxyethyl)phosphine) is a reducing agent frequently used in biochemistry and molecular biology applications. It is often prepared and used as a hydrochloride salt (TCEP-HCl) with a molecular weight of 286.65 gram/mol. It is soluble in water and available as a stabilized solution at neutral pH and immobilized onto an agarose support to facilitate removal of the reducing agent.
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.
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.