If you have been reading about REV-ERB and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Last reviewed on 2026-01-14. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
Laboratory studies often administer SR9009 by injection because oral absorption appears poor in rodents. Reported pharmacokinetic properties include rapid metabolism and low systemic exposure after oral dosing. Human pharmacokinetic data are sparse, so absorption, distribution, metabolism, and excretion in people are not well defined. Some research explores related REV-ERB compounds with improved drug-like properties. Regulatory approval for any REV-ERB agonist as a human medicine has not been granted to date.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic small molecule | Studied as a REV-ERB agonist |
| Molecular formula | C20H24ClN3O4S | Reported for the neutral compound |
| Appearance | Off-white to pale yellow solid | Typical research-grade material |
| Solubility | Sparingly soluble in water | Soluble in solvents such as DMSO |
| Common synonyms | SR9009; Stenabolic | Stenabolic is an informal alias |
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.
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.
In 1979, the Sandinista National Liberation Front (FSLN) led by Daniel Ortega won the Nicaraguan Revolution (1961–1990) against the government of Anastasio Somoza Debayle (1 December 1974 – 17 July 1979) to establish a socialist Nicaragua. Within months, the government of Ronald Reagan sponsored the counter-revolutionary Contras in the secret Contra War (1979–1990) against the Sandinista government. In 1989, the Contra War concluded with the signing of the Tela Accord at the port of Tela, Honduras. The Tela Accord required the subsequent, voluntary demobilisation of the Contra guerrilla armies and the FSLN army. In 1990, a second national election installed to government a majority of non-Sandinista political parties, to whom the FSLN handed political power. Since 2006, the FSLN has returned to government, winning every legislative and presidential election in the process (2006, 2011 and 2016). The Salvadoran Civil War (1979–1992) featured the popularly supported Farabundo Martí National Liberation Front, an organisation of left-wing parties fighting against the right-wing military government of El Salvador. In 1983, the United States invasion of Grenada (25–29 October 1983) thwarted the assumption of power by the elected government of the New Jewel Movement (1973–1983), a Marxist–Leninist vanguard party led by Maurice Bishop.
== Applications == The aldehyde tag is a technique which recently found increased application because of the introduction of bioorthogonal chemical reporters. Bioorthogonal agents contain functional groups such as azides or cyclooctynes for coupling which are not naturally found in the cell. Due to their foreignness, they seem inert and do not disrupt the native metabolism, Fig. 3 gives an overview of possible labeling methods for formylglycine. For example, it can be coupled to probes such as biotin or a protein tag like Flag that are useful for purification and detection. Furthermore, fluorophores can be directly conjugated for live cell imaging. The conjugation of polyethylene glycol (PEG) chains to potential drug candidates extends the stability against proteases in body fluids and at the same time reduces renal clearance and immunogenicity. The first application described here, deals with the formation of protein-protein conjugates through bioorthogonal probes. Since, the aldehyde tag is strictly speaking not a true bioorthogonal agent as it can be found in various metabolites, it can cause cross reactions during protein labeling. However, coupling bioorthogonal probes such as azides or cyclooctynes can be applied to overcome this obstacle. As a second application, the coupling of glycan moieties to proteins is presented here. It can be utilised in the strategy of chemically introduced glycosylation patterns.
Human activities have caused population decreases or extinction in many bird species. Over a hundred bird species have gone extinct in historical times, although the most dramatic human-caused avian extinctions, eradicating an estimated 750–1800 species, occurred during the human colonisation of Melanesian, Polynesian, and Micronesian islands. Many bird populations are declining worldwide, with 1,227 species listed as threatened by BirdLife International and the IUCN in 2009. There have been long-term declines in North American bird populations, with an estimated loss of 2.9 billion breeding adults, about 30% of the total, since 1970. The most commonly cited human threat to birds is habitat loss. Other threats include overhunting, collisions with buildings or vehicles, long-line fishing bycatch, pollution (including oil spills and pesticide use), competition and predation from nonnative invasive species, and climate change. Governments and conservation groups work to protect birds, either by passing laws that preserve and restore bird habitat or by establishing captive populations for reintroductions. Such projects have produced some successes; one study estimated that conservation efforts saved 16 species of bird that would otherwise have gone extinct between 1994 and 2004, including the California condor and Norfolk parakeet. Human activities have allowed the expansion of a few temperate area species, such as the barn swallow and European starling.
Sources: en.wikipedia.org
== Research == Much of Limbird's research has explored the activity of G-protein coupled receptors. She has demonstrated how alpha-2 adrenergic receptors are involved in regulation of blood pressure, suppression of pain, sedation and the action of opioid drugs. She has developed techniques for selectively manipulating such receptors. Limbird is the author of Cell Surface Receptors: A Short Course in Theory and Methods (1985, 1996, 2004); co-editor with Joel Hardman of the 9th (1995) and 10th (2001) editions of Goodman and Gilman’s Pharmacological Basis of Therapeutics; editor of Alpha2-Adrenergic Receptors (1988) and co-editor with Stephen Lanier of α2-Adrenergic Receptors. Structure, Function and Therapeutic Implications (1996). Limbird has served on the editorial boards of the Journal of Biological Chemistry, the American Journal of Physiology, and Molecular Pharmacology.
== Xenon-124 == Xenon-124 is an isotope of xenon that undergoes double electron capture to tellurium-124 with a very long half-life of 1.1×1022 years, approximately 12 orders of magnitude longer than the age of the universe. This decay was observed in the XENON1T detector in 2019, and is the slowest one ever directly observed. (Even slower decays of other nuclei have been measured, but by detecting decay products that have accumulated over billions of years rather than observing them directly.)
Tin-121m (121mSn) is a nuclear isomer of tin with a half-life of 43.9 years, making it technically a medium-lived fission product. In a normal thermal reactor, it has a very low fission product yield; thus, this isotope is not a significant contributor to nuclear waste. Fast fission or fission of some heavier actinides will produce it at higher yields. For example, its yield from uranium-235 is 0.0007% per thermal fission and 0.002% per fast fission.
Sources: en.wikipedia.org
The common death adder (Acanthophis antarcticus) is a highly venomous snake species with a 50–60% untreated mortality rate. It is also the fastest striking venomous snake in the world. A death adder can go from a strike position, to strike and envenoming their prey, and back to strike position again, in less than 0.15 seconds. The SC LD50 value is 0.4 mg/kg and the venom yield per bite can range anywhere from 70–236 mg. Unlike other snakes that flee from approaching humans crashing through the undergrowth, common death adders are more likely to sit tight and risk being stepped on, making them more dangerous to the unwary bushwalker. They are said to be reluctant to bite unless actually touched.
Tyne and Wear () is a ceremonial county in North East England. It borders Northumberland to the north and County Durham to the south. The county contains the two cities of Newcastle upon Tyne and Sunderland. The notable towns in the county are Birtley, Blaydon Felling, Gateshead, Hebburn, Hetton-le-Hole, Houghton-le-Spring, Jarrow, Killingworth, North Shields, South Shields, Tynemouth, Wallsend, Washington and Whitley Bay. The county is largely urbanised, with an area of 540 square kilometres (210 sq mi) and an estimated population of 1,178,389 in 2024. Newcastle is on the north bank of the River Tyne in the centre of the county, and Gateshead opposite on the south bank. South Shields lies in the east at the river's mouth, and the city of Sunderland in the south-east at the mouth of the River Wear. Nearly all of the county's settlements belong to the Tyneside or Wearside conurbations, the latter of which extends into County Durham. For local government purposes Tyne and Wear comprises five metropolitan boroughs: Gateshead, Newcastle upon Tyne, Sunderland, North Tyneside and South Tyneside. The borough councils collaborate through the North East Combined Authority, which also includes Durham County Council and Northumberland County Council. The county was created in 1974 from south-east Northumberland and north-east County Durham. The most notable geographic features of the county are the River Tyne and River Wear, after which it is named and along which its major settlements developed.
Vitamin K2, the main storage form in animals, has several subtypes, which differ in isoprenoid chain length. These vitamin K2 homologues are called menaquinones, and are characterized by the number of isoprenoid residues in their side chains. Menaquinones are abbreviated MK-n, where M stands for menaquinone, the K stands for vitamin K, and the n represents the number of isoprenoid side chain residues. For example, menaquinone-4 (abbreviated MK-4) has four isoprene residues in its side chain. Menaquinone-4 (also known as menatetrenone from its four isoprene residues) is the most common type of vitamin K2 in animal products since MK-4 is normally synthesized from vitamin K1 in certain animal tissues (arterial walls, pancreas, and testes) by replacement of the phytyl tail with an unsaturated geranylgeranyl tail containing four isoprene units, thus yielding menaquinone-4 which is water soluble in nature. This homolog of vitamin K2 may have enzyme functions distinct from those of vitamin K1. MK-7 and other long-chain menaquinones are different from MK-4 in that they are not produced by human tissue. MK-7 may be converted from phylloquinone (K1) in the colon by Escherichia coli bacteria. However, these menaquinones synthesized by bacteria in the gut appear to contribute minimally to overall vitamin K status. MK-4 and MK-7 are both found in the United States in dietary supplements for bone health.
Sources: en.wikipedia.org
SR9009 is a synthetic research compound that activates the REV-ERBα and REV-ERBβ nuclear receptors. It is not an approved drug and has no established human therapeutic use. Most published biological data come from cell and rodent studies.
No. SR9009 is frequently mislabeled as a SARM in online discussions, but it does not target androgen receptors. Its known mechanism involves REV-ERB nuclear receptors and circadian-metabolic gene regulation.
Human clinical data are very limited. There is no approved human use, and safety and efficacy in people are not established. Most evidence comes from preclinical models, so effects observed in animals may not apply to humans.
SR9009 is a synthetic research compound that binds and modulates the nuclear receptors REV-ERBα and REV-ERBβ. It is used in laboratory studies of circadian biology and metabolism, not as an approved medicine. It is also known by the informal name Stenabolic.