circadian clock 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 2026-01-21. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
Storage conditions for research-grade SR9009 generally involve a freezer at approximately minus twenty degrees Celsius, sometimes lower for long-term preservation. Containers should remain tightly closed and protected from light. Desiccants may be used to limit moisture uptake. Solutions are often stored in aliquots to avoid repeated warming and cooling. Stability data for the compound under various conditions are limited, so laboratories typically follow supplier recommendations and verify performance through periodic analytical checks rather than assuming indefinite stability.
Identity and purity testing for SR9009 commonly uses liquid chromatography coupled with tandem mass spectrometry. This method separates the compound from matrix components and detects it by mass-to-charge transitions, providing sensitive and specific confirmation. Nuclear magnetic resonance spectroscopy can support structural identification, while high-performance liquid chromatography with ultraviolet detection may estimate purity. Because online products labeled as SR9009 may contain other substances or no active compound at all, independent verification is important in research settings. Certificates of analysis are useful but not a substitute for in-house testing.
Laboratory samples of SR9009 are typically supplied as a white to off-white powder. The compound dissolves readily in organic solvents such as dimethyl sulfoxide and ethanol, while its solubility in water is low. Because of this solubility profile, researchers often prepare concentrated stock solutions in an organic solvent before diluting them into aqueous assay buffers. Light exposure, moisture, and repeated freeze-thaw cycles can degrade many small molecules, so handling procedures usually aim to minimize these factors. Purity is commonly checked before use.
| 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. |
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.
SR9009 binds REV-ERB receptors and alters their repressive activity on target genes. This action can change transcription of genes involved in lipid handling, glucose metabolism, and mitochondrial function. In rodent studies, treated animals have shown changes in muscle oxidative capacity and exercise performance, though effects vary by dose, duration, and model. The precise molecular steps connecting receptor binding to whole-body outcomes are still an active area of investigation. Findings in animals do not automatically translate to humans.
Because REV-ERB receptors are core clock components, SR9009 has been examined for effects on daily rhythms as well as metabolism. Research has explored whether the compound can shift or reinforce circadian gene expression in tissues such as liver and muscle. Some studies report improved metabolic markers in obese or diabetic mice, while others show context-dependent responses. Questions remain about which effects are direct, which are secondary to timing, and how they might differ across species.
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.
At the molecular level, SR9009 binds REV-ERBα and REV-ERBβ and alters their repressive activity on target genes. These nuclear receptors help regulate the circadian clock, lipid synthesis, glucose metabolism, and inflammatory pathways. By changing transcription, the compound can shift the timing or magnitude of downstream metabolic processes in model systems. It does not act through androgen receptors or adenosine receptors, which distinguishes it from several substances sold for athletic performance. Whether the same transcriptional changes occur in humans at tolerable exposures remains an open question because controlled human studies are lacking.
Preclinical reports describe effects on exercise endurance, mitochondrial content, and lipid profiles in rodents, but these findings come from specific experimental conditions. Many studies use high doses or delivery methods that may not translate directly to human use. SR9009 has been reported to have low oral bioavailability and a short half-life, which complicates interpretation of oral dosing studies. It is not established as safe or effective for any indication. Literature discussions often separate its pharmacological mechanism from unverified claims made in fitness and supplement markets.
== Applications == Proteinase K is commonly used in molecular biology to digest protein and remove contamination from preparations of nucleic acid. Addition of Proteinase K to nucleic acid preparations rapidly inactivates nucleases that might otherwise degrade the DNA or RNA during purification. It is highly suited to this application since the enzyme is active in the presence of chemicals that denature proteins, such as SDS and urea, chelating agents such as EDTA, sulfhydryl reagents, as well as trypsin or chymotrypsin inhibitors. Proteinase K is used for the destruction of proteins in cell lysates (tissue, cell culture cells) and for the release of nucleic acids, since it very effectively inactivates DNases and RNases. Some examples for applications: Proteinase K is very useful in the isolation of highly native, undamaged DNAs or RNAs, since most microbial or mammalian DNases and RNases are rapidly inactivated by the enzyme, particularly in the presence of 0.5–1% SDS. The enzyme's activity towards native proteins is stimulated by denaturants such as SDS. In contrast, when measured using peptide substrates, denaturants inhibit the enzyme. The reason for this result is that the denaturing agents unfold the protein substrates and make them more accessible to the protease.
His grade point average during his first three years at Yale was 77, and he had a similar average under a nonnumerical rating system in his final year. In the fall of 1973, Bush entered Harvard Business School. He graduated in 1975 with a Master of Business Administration. He is the only U.S. president to have earned that degree.
Fluorescent proteins with other chromophores, such as UnaG with bilirubin, can display unique properties like red-shifted emission above 600 nm or photoconversion from a green-emitting state to a red-emitting state. They can have excitation and emission wavelengths far enough apart to achieve conversion between red and green light. A new class of fluorescent protein was engineered from α-allophycocyanin, a phycobiliprotein found in the cyanobacterium Trichodesmium erythraeum, and was named small ultra red fluorescent protein (smURFP) in 2016. smURFP autocatalytically incorporates the chromophore biliverdin without the need for an external protein known as a lyase. Jellyfish- and coral-derived GFP-like proteins require oxygen and produce a stoichiometric amount of hydrogen peroxide upon chromophore formation. smURFP does not require oxygen or produce hydrogen peroxide. smURFP has a large extinction coefficient (180,000 M−1 cm−1) and has a modest quantum yield (0.20), which makes it comparable biophysical brightness to eGFP and ~2-fold brighter than most red or far-red fluorescent proteins derived from coral. smURFP spectral properties are similar to the organic dye Cy5.
== Extraction == Extraction using superheated water tends to be fast because diffusion rates increase with temperature. Organic materials tend to increase in solubility with temperature, but not all at the same rate. For example, in extraction of essential oils from rosemary and coriander, the more valuable oxygenated terpenes were extracted much faster than the hydrocarbons. Therefore, extraction with superheated water can be both selective and rapid, and has been used to fractionate diesel and woodsmoke particulates. Superheated water is being used commercially to extract starch material from marsh mallow root for skincare applications and to remove low levels of metals from a high-temperature resistant polymer. For analytical purposes, superheated water can replace organic solvents in many applications, for example extraction of PAHs from soils and can also be used on a large scale to remediate contaminated soils, by either extraction alone or extraction linked to supercritical or wet oxidation.
Sources: en.wikipedia.org
Joshua Coon is a professor of chemistry and biomolecular chemistry and the inaugural holder of the Thomas and Margaret Pyle Chair at the University of Wisconsin–Madison, and an affiliate of the Morgridge Institute for Research. Coon develops scientific instruments to measure molecules in living systems. He focuses specifically on the use of mass spectrometry to measure the molecular mass of biomolecules, and its application to proteomics. Joshua Coon, along with John Syka, developed electron-transfer dissociation (ETD) while working as a postdoctoral student in Donald Hunt's lab at the University of Virginia.
Of his character, he said: "Originally, I was married. I had this kid and I did this research and I didn't know that what I was researching had this effect. And someone got killed and I had these regrets and I'm trying to stop what I'm doing, but they can't let me so they're chasing me. And then all of a sudden I turn into this 24-year-old machinist and I turned to (director) Andrew Davis and I said, 'What happened to the movie I said yes to? What happened to that script? Where did that go?' And he said, 'No, I got something better,' and so I just had to go with it."
=== Immune system === Strong statistical evidence links vitiligo to changes in the immune system. It is thought to be caused by the immune system attacking and destroying melanocytes. Variations in genes expressed in immune cells or melanocytes have been associated with the disorder. A genome-wide association study found approximately 36 independent susceptibility loci for generalized vitiligo. One of them is the gene that encodes the protein tyrosinase, a melanocyte enzyme that catalyzes melanin biosynthesis and is a major autoantigen in generalized vitiligo. It has been hypothesized that damaging environmental factors can disrupt redox reactions necessary for protein folding, so skin cells may initiate the unfolded protein response, which releases cytokines and thus triggers an immune response. Additionally, artificial sweeteners such as sucralose can make gut bacteria more aggressive, potentially damaging pigment-producing cells. Vitiligo is sometimes associated with autoimmune and inflammatory diseases such as Hashimoto's thyroiditis, scleroderma, rheumatoid arthritis, type 1 diabetes mellitus, psoriasis, Addison's disease, pernicious anemia, alopecia areata, systemic lupus erythematosus, and celiac disease. Among the inflammatory products of NLRP1 are caspase 1 and caspase 7, which activate the inflammatory cytokine interleukin-1β. Interleukin-1β and interleukin-18 are expressed at high levels in people with vitiligo. In one of the mutations, the amino acid leucine in the NALP1 protein was replaced by histidine (Leu155 → His).
Rheumatoid arthritis and other diseases that cause inflammation of the flexor tendons. With severe untreated hypothyroidism, generalized myxedema causes deposition of mucopolysaccharides within both the perineurium of the median nerve, as well as the tendons passing through the carpal tunnel. Association of CTS with lesser degrees of hypothyroidism is questioned. Pregnancy may bring out symptoms in genetically predisposed individuals, which may be caused by the temporary changes in hormones and fluids, which increase pressure in the carpal tunnel. High progesterone levels and water retention may increase the size of the synovium. Bleeding and swelling from a fracture or dislocation. This is referred to as acute carpal tunnel syndrome. Acromegaly causes excessive secretion of growth hormones. This causes the soft tissues and bones around the carpal tunnel to grow and compress the median nerve.
== Metabonomics == Metabonomics is defined as "the quantitative measurement of the dynamic multiparametric metabolic response of living systems to pathophysiological stimuli or genetic modification". The word origin is from the Greek μεταβολή meaning change and nomos meaning a rule set or set of laws. This approach was pioneered by Jeremy Nicholson at Murdoch University and has been used in toxicology, disease diagnosis and a number of other fields. Historically, the metabonomics approach was one of the first methods to apply the scope of systems biology to studies of metabolism. There has been some disagreement over the exact differences between 'metabolomics' and 'metabonomics'. The difference between the two terms is not related to choice of analytical platform: although metabonomics is more associated with NMR spectroscopy and metabolomics with mass spectrometry-based techniques, this is simply because of usages amongst different groups that have popularized the different terms. While there is still no absolute agreement, there is a growing consensus that 'metabolomics' places a greater emphasis on metabolic profiling at a cellular or organ level and is primarily concerned with normal endogenous metabolism. 'Metabonomics' extends metabolic profiling to include information about perturbations of metabolism caused by environmental factors (including diet and toxins), disease processes, and the involvement of extragenomic influences, such as gut microflora.
Sources: en.wikipedia.org
Cataracts: Extended usage of corticosteroids may cause clouding at the back of the lens, also known as posterior subcapsular cataract. This type of cataract reduces the path of light reaching the eye, which interferes with a person's reading vision. Consumption of prednisolone eye drops post-surgery may also retard the healing process. Corneal thinning: When corticosteroids are used in the long term, corneal and scleral thinning is also one of the consequences. When not ceased, thinning may ultimately lead to perforation of the cornea. Glaucoma: Prolonged use of corticosteroids has a chance of causing a raised intraocular pressure (IOP), injuring the optic nerve and weakening visual awareness. Corticosteroids should be used cautiously in patients with concomitant conditions of glaucoma. Doctors track patients' IOP if they are using corticosteroid eye drops for more than 103 days.
Alistair Darling, Baron Darling of Roulanish, 70, British politician, chancellor of the Exchequer (2007–2010), MP (1987–2015) and member of the House of Lords (2015–2020). 1 December – Brigit Forsyth, 83, Scottish actress (Whatever Happened to the Likely Lads?, Boon, Still Open All Hours). 10 December – Willie McCulloch, 75, Scottish football player (Alloa Athletic, Airdrieonians) and manager (Cowdenbeath). (death announced on this date) 14 December – Hanzala Malik, 67, Scottish politician, MSP (2011–2016). (death announced on this date) 19 December – Sir Norman Arthur, 92, British military officer and Olympic equestrian (1960), GOC Scotland (1985–1988) and Lord Lieutenant of Kirkcudbright (1996–2006). (death announced on this date) 27 December – Jack McLean, 78, Scottish journalist and art teacher.
eV, higher than what is predicted in theory for continuum plates of the same thickness, due to nonlocal microstructural constraints such as nonlocal coupling of particle rotational degrees of freedom. On the other hand, resistance to bending is found to be greatly reduced in nanoparticle monolayers that are supported at the air/water interface, possibly due to screening of ligand interactions in a wet environment.
== In fiction == Robert Harris's 1992 novel Fatherland takes place in an alternate history in which Nazi Germany won World War II and in which the Volkshalle was actually built. Several of the book's scenes take place in and around it. Harris carefully used Speer's plans, with the building being depicted as being 300 m (1,000 ft) tall. As depicted in the book, the building would indeed have had its own "weather", with the breathing and perspiration of 150,000 occupants precipitating in the high dome; but rather than considering this a problem, Nazi propaganda would boast of it. In a real-world corollary to the fiction concerning the Volkshalle, morning fog can roll into the Kennedy Space Center's immense Vehicle Assembly Building, leading to "clouds" being observed inside the building. The Volkshalle appears in the alternate history novel In the Presence of Mine Enemies by Harry Turtledove, being used for the lying in state for the deceased Führer, Kurt Haldweim. The Volkshalle's image appears in the video game Wolfenstein: The New Order, in an alternate 1960s in which (like the Fatherland novel) Nazi Germany won World War II. Computer-generated imagery is used to depict the Volkshalle in an alternate history Berlin in the TV production of The Man in the High Castle. Multiple scenes in seasons two to four take place inside various parts of the Volkshalle. Unlike most other depictions of the Volkshalle, it was shown to have housed the Führer's Office and residence.
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.
Research-grade SR9009 is typically stored frozen at about minus twenty degrees Celsius, protected from light and moisture. Stock solutions are often kept in aliquots to avoid repeated freeze-thaw cycles. Specific storage conditions should follow the supplier's documentation.