This is a working overview of circadian rhythm, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2025-07-23 and is reviewed periodically as new material appears.
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.
Handling practices for SR9009 focus on minimizing degradation and contamination. The solid is generally stored desiccated at or below -20 °C, protected from light and moisture. Stock solutions are often prepared in dimethyl sulfoxide or ethanol, then aliquoted to avoid repeated freeze–thaw cycles. Aqueous solubility is low, so formulations for animal studies may require cosolvents or suspending agents. Personnel should follow institutional chemical safety procedures, because toxicological data for humans are incomplete.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Appearance | White to off-white solid | Visual inspection is not sufficient for identity. |
| Solubility | Soluble in DMSO and ethanol | Low solubility in water. |
| Typical storage | -20 °C, desiccated, dark | Protect from repeated temperature changes. |
| Common analytical method | LC-MS or HPLC-UV | Reference standard required for comparison. |
| Common synonyms | SR9009; Stenabolic; REV-ERB agonist | Vendor naming may vary. |
SR9009 is a synthetic small molecule studied as an agonist of the nuclear receptors REV-ERBα and REV-ERBβ, also called NR1D1 and NR1D2. These receptors help regulate circadian rhythms and metabolic gene programs. The compound was developed for laboratory research, not as an approved therapeutic. Its identity is distinct from steroid hormones and selective androgen receptor modulators. Scientific interest centers on how REV-ERB activation changes gene expression in cells and animal models.
At the molecular level, SR9009 binds the ligand-binding domain of REV-ERB and strengthens recruitment of corepressor proteins such as NCoR and HDAC3. This increases repression of target genes, including Bmal1 and other clock-controlled and metabolic genes. In rodent studies, such changes have been linked to altered lipid handling, glucose metabolism, and energy expenditure. The precise chain of events between receptor binding and whole-body effects remains an active area of research. Findings in animals do not automatically translate to humans.
REV-ERB proteins typically suppress gene expression by recruiting corepressor complexes to DNA response elements. SR9009 binds these receptors and strengthens that repressive action in cell-based assays. Studies in rodents have reported changes in lipid handling, mitochondrial function, and exercise capacity after treatment. Such findings are often cited as evidence for metabolic effects, but species differences and limited pharmacokinetic data make direct translation to humans uncertain. Researchers continue to examine which effects are robust and which depend on specific experimental conditions.
SR9009 is frequently discussed alongside other REV-ERB ligands, including synthetic agonists and natural heme-related molecules. Its selectivity for REV-ERB over related nuclear receptors has been measured in binding and reporter assays, though off-target activity at higher concentrations is possible. The compound is prohibited in sport by the World Anti-Doping Agency, and it is not approved for any medical use in major jurisdictions. Products sold online may be labeled as research chemicals, and their identity and purity are not guaranteed by regulatory review.
SR9009 is a synthetic small molecule that acts on the nuclear receptors REV-ERBα and REV-ERBβ. These receptors are part of the circadian clock machinery and normally repress transcription of certain target genes. In laboratory research, SR9009 is used as a chemical tool to study how REV-ERB activity influences metabolism, inflammation, and daily biological rhythms. The compound is not an approved medicine, and its effects in humans remain largely uncharacterized. It is often described as an investigational agent rather than a therapeutic product.
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.
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.
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.
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.
In accordance with its low DAT occupancy, no measurable dopamine release in the human brain was detected with bupropion (one 150 mg dose) in a PET study. Bupropion has also been shown to increase reuptake of dopamine by striatal VMAT2, though it is unknown if this effect is more pronounced than other DRIs. These findings raise questions about the role of dopamine reuptake inhibition in the pharmacology of bupropion, and suggest that other actions may be responsible for its therapeutic effects. No data are available on occupancy of the norepinephrine transporter (NET) by bupropion and its metabolites. However, due to the increased exposure of hydroxybupropion over bupropion itself, which has higher affinity for the NET than the DAT, bupropion's overall pharmacological profile in humans may end up making it effectively more of a norepinephrine reuptake inhibitor (NRI) than a dopamine reuptake inhibitor. Accordingly, the clinical effects of bupropion are more consistent with noradrenergic activity than with dopaminergic actions. However, in contrast to other NRIs like atomoxetine and reboxetine, but similarly to methylphenidate, bupropion fails to alter the clinical tyramine pressor response, an index of norepinephrine reuptake inhibition.
P7C3 (pool 7, compound 3) is a drug related to latrepirdine (dimebon) which has neuroprotective and proneurogenic effects and may be potentially useful for the treatment of Alzheimer's disease and similar neurodegenerative disorders. The pharmacological effects of P7C3 in vitro resemble those of endogenous proneurogenic peptides such as fibroblast growth factor 1 (FGF-1), and the proneurogenic activity of P7C3 was around thirty times that of latrepirdine when they were compared in mice. P7C3 was chosen for further animal studies on the basis of favorable pharmacokinetic factors, such as its high oral bioavailability and long duration of action, but several other related compounds showed similar activity such as the more potent fluorinated analogue P7C3-A20 which is up to ten times stronger again, and the methoxy analogue P7C3-OMe, for which it was determined that the (R) enantiomer is the active form.
== Analysis == Urea is readily quantified by a number of different methods, such as the diacetyl monoxime colorimetric method, and the Berthelot reaction (after initial conversion of urea to ammonia via urease). These methods are amenable to high throughput instrumentation, such as automated flow injection analyzers and 96-well micro-plate spectrophotometers.
Accordingly, following critical evaluation to ensure comprehensive, quantitative analysis, new approaches can also be integrated as the critical front-end of analysis once fully vetted for their ability to resolve a full breadth of intact proteoforms inherent to proteomes, as can a variety of proteases and LC/MS/MS adaptations to ensure the highest quality peptide analyses and thus proteoform identifications
Sources: en.wikipedia.org
Silica (glass) can be used to bend or stop lights in their tracks. Developing countries also use silicone to make circuits for the fluids used in pathogen detection. Nano-construct synthesis leads to the self-assembly of the building blocks into functional structures that may be useful for electronic, photonic, medical, or bioanalytical problems. Nanochemical methods can be used to create carbon nanomaterials such as carbon nanotubes, graphene, and fullerenes which have gained attention in recent years due to their remarkable mechanical and electrical properties.
Even more surprising, the researchers determined that the girl's mother's genome was more closely related to Western European Neanderthal DNA, excavated thousands of miles away at the Vindija Cave, Croatia, than the Neanderthals who lived in the Siberian cave where her daughter's remains were found. This finding suggests that Neanderthals migrated in multiple waves from Western Europe to Central Eurasia and encountered the Denisovans several times over a span of tens of thousands of years, and possibly coexisted with them for periods of time.
Nonbenzodiazepines also bind to the benzodiazepine binding site on the GABAA receptor and possess similar pharmacological properties. While the nonbenzodiazepines are by definition structurally unrelated to the benzodiazepines, both classes of drugs possess a common pharmacophore (see figure to the lower-right), which explains their binding to a common receptor site. Not all benzodiazepines increase the conductance of the GABAA receptor. Flumazenil, an imidazobenzodiazepine, is an antidote for some benzodiazepine overdoses. The structural scaffold can even be used to target receptors other than GABAA.
Sources: en.wikipedia.org
=== Odor === Feces possesses physiological odor, which can vary according to diet and health status. For example, meat protein is rich in the amino acid methionine, which is a precursor of the sulfur-containing odorous compounds listed below. The odor of human feces is suggested to be made up from the following odorant volatiles:
=== Available forms === Tiagabine is available in the form of 2, 4, 5, 10, 12, 15, and 16 mg oral tablets. The drug is taken 1 to 4 times per day due to its short elimination half-life. A sustained-release formulation would be advantageous but has not been developed or marketed.
Carindacillin (INN), also known as carbenicillin indanyl (USAN), is a penicillin antibiotic. It is a prodrug of carbenicillin. It is administered orally, as the sodium salt. It was formerly marketed in the United States by Pfizer under the brand name Geocillin. Pfizer withdrew Carindacillin from the U.S. market sometime after 2008.
Fish and Wildlife Service declares 23 species extinct, due to a combination of development, invasive species, logging and pollution. September 30 Britney Spears' father Jamie Spears is formally suspended as the conservator of her estate. President Biden signs legislation that would extend funding for the U.S. government through December 3, thereby avoiding a government shutdown. Government funds were due to run out at midnight.
Sources: en.wikipedia.org
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.
The solid is usually kept desiccated at -20 °C or lower and protected from light. Stock solutions are aliquoted to limit freeze–thaw cycles. Aqueous solutions are not generally recommended for long-term storage.
Laws differ by country and by intended use. It is not an approved medicine, and many vendors sell it as a research chemical. Purchasers are responsible for confirming local restrictions.
It is a synthetic compound studied as an agonist of REV-ERB nuclear receptors. It is not an approved medicine and has mainly been examined in laboratory and animal research.