If you have been reading about circadian rhythm 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.
Updated 2025-11-18. Numbers and descriptions here follow the published literature rather than marketing material.
Detection of SR9009 in biological samples usually employs liquid chromatography coupled with tandem mass spectrometry. This method can identify the parent compound and sometimes metabolites in urine or blood. Because exposure can be low and clearance may be rapid, sample timing and limits of detection matter. Laboratories validate assays for sensitivity and specificity. Results are interpreted alongside chain-of-custody and quality-control records. Urine is the common matrix for anti-doping analysis, while blood may be used in research settings.
Handling recommendations for SR9009 in a laboratory setting include storing the solid at low temperature, protected from light and moisture. The compound is often dissolved in dimethyl sulfoxide or ethanol for experiments. Solutions should be prepared with appropriate personal protective equipment and disposed of according to local rules. Stability data for long-term storage are limited, so stock solutions are typically kept cold and used within defined periods. Records of preparation date and concentration support reproducibility.
SR9009 is not approved as a medicine by major regulatory agencies. It is commonly sold as a research chemical, a category that may fall outside customary drug approval and quality rules. In sports, the World Anti-Doping Agency lists SR9009 as a prohibited substance. Athletes who use it can face sanctions if it is detected in a sample. Legal status varies by country, and importation may be restricted. Enforcement practices differ across borders.
Laboratory identification of SR9009 typically relies on chromatographic separation coupled to mass spectrometry, often with ultraviolet detection as a secondary check. Nuclear magnetic resonance spectroscopy can confirm molecular structure when a reference standard is available. Because many suppliers sell the compound as a research chemical, independent identity testing is important for experimental reproducibility. A single retention time is not sufficient proof of identity, especially when related compounds may be present. Purity assessments usually report a percentage based on area normalization.
SR9009 is generally described as poorly soluble in water and more soluble in organic solvents such as dimethyl sulfoxide and ethanol. Stock solutions are commonly prepared in an organic solvent before dilution into an aqueous buffer or vehicle. Precipitation can occur if the organic fraction is reduced too quickly or if the final concentration exceeds the compound's solubility limit. Sonication or gentle warming may aid dissolution in some protocols, but excessive heat can promote degradation. Container material and pH can also influence observed solubility.
For long-term storage, SR9009 is typically kept as a solid at low temperature, protected from moisture and light. Desiccated conditions limit hydrolysis, while opaque containers reduce photochemical breakdown. Solutions are less stable than solids and are often stored frozen in aliquots to avoid repeated freeze-thaw cycles. Stability data are not standardized across all suppliers, so users should rely on certificate-of-analysis information when available. Degradation may appear as color change, precipitate, or decreased chromatographic purity.
| Property | Value | Notes |
|---|---|---|
| Regulatory status | Not approved as a medicine in major jurisdictions | Sold as a research chemical; legal status varies |
| Anti-doping status | Prohibited by the World Anti-Doping Agency | Listed under non-approved substances or related category |
| Typical analytical method | LC-MS/MS | Used for detection and confirmation in biological samples |
| Storage temperature | −20 °C or lower for solid | Desiccated and protected from light |
| Common solution solvents | DMSO; ethanol | Aqueous solubility is limited |
Preclinical reports have linked SR9009 to improved endurance and altered energy expenditure in rodents. Such findings have prompted interest in whether REV-ERB activation can influence skeletal muscle metabolism. However, the reported effects depend on dose, route, and experimental model, and replication across laboratories is limited. Human trials have not established comparable outcomes, so claims about exercise performance remain speculative. The absence of controlled human data is a central limitation in interpreting these observations.
The mechanism of action involves binding to REV-ERB receptors and recruiting corepressor complexes, which represses target gene transcription. This contrasts with many nuclear receptor agonists that activate transcription. Downstream effects may include changes in autophagy, mitochondrial biogenesis, and lipid handling, but the precise pathways remain an active area of study. Whether these molecular events translate into meaningful physiological effects in humans is unresolved. Most evidence comes from cultured cells and rodent models rather than human participants.
SR9009 is a synthetic small molecule developed as an agonist of the nuclear receptors REV-ERBα (NR1D1) and REV-ERBβ (NR1D2). These receptors help regulate circadian rhythms and metabolic gene expression. In cell and animal studies, SR9009 alters transcription of genes involved in lipid metabolism, inflammation, and mitochondrial function. It is not an approved medicine, and its pharmacological profile in humans remains largely uncharacterized. The compound is frequently discussed in the context of circadian biology and metabolic research rather than clinical use.
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 studied as an agonist of the nuclear receptors REV-ERBα and REV-ERBβ. It is not an approved medicine and has no established human therapeutic use. The compound appears in scientific literature as a tool for probing circadian and metabolic regulation. Online sellers often label it as a research chemical, sometimes using the nickname Stenabolic. Its chemical identity is distinct from selective androgen receptor modulators, stimulants, and peroxisome proliferator-activated receptor delta agonists. Researchers use it mainly in cell and animal experiments.
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.
A radionuclide (radioactive nuclide, radioisotope, radioactive isotope, or unstable isotope) is a nuclide that is unstable and known to undergo radioactive decay into a different nuclide, which may be another radionuclide (see decay chain) or be stable. Radioactive decay is a random process at the level of single atoms: it is impossible to predict when one particular atom will decay. For a collection of atoms of a single nuclide, their average decay rate can be measured, and its half-life (t1/2) calculated. Half-lives vary by 55 orders of magnitude and have no known limits. All chemical elements have radionuclides - even the lightest, hydrogen, has a well-known radionuclide, tritium (though helium, lithium, and boron have none with half-life over a second). Elements heavier than lead (Z > 82), and the elements technetium and promethium, have only radionuclides and do not exist in stable forms, though bismuth can be treated as stable with the half-life of its natural isotope being over a trillion times longer than the current age of the universe. Radiation emitted by radionuclides is almost always ionizing radiation and exposure above a certain level can cause damage to living organisms.
The Biden administration's attempts to implement student loan forgiveness and relief programs have faced legal challenges from a coalition of Republican-led states. Biden's plans to forgive student loan debt were estimated to cost over $519 billion, and some critics called them a "disaster".
==== Documentaries without words ==== Films in the documentary form without words have been made. Listen to Britain, directed by Humphrey Jennings and Stuart McAllister in 1942, is a wordless meditation on wartime Britain. From 1982, the Qatsi trilogy and the similar Baraka could be described as visual tone poems, with music related to the images, but no spoken content. Koyaanisqatsi (part of the Qatsi trilogy) consists primarily of slow motion and time-lapse photography of cities and many natural landscapes across the United States. Baraka tries to capture the great pulse of humanity as it flocks and swarms in daily activity and religious ceremonies. Bodysong was made in 2003 and won a British Independent Film Award for "Best British Documentary." The 2004 film Genesis shows animal and plant life in states of expansion, decay, sex, and death, with some, but little, narration.
Sources: en.wikipedia.org
Its objectives include comparison of survival, cardiovascular mortality and morbidity, pharmacological activity (e.g., suppression of testosterone levels), other side effects and toxicities, and quality of life. In addition to the PATCH trial, the Systemic Therapy in Advancing or Metastatic Prostate Cancer: Evaluation of Drug Efficacy (STAMPEDE) study added a high-dose estradiol patches arm (~2,000 men) in July 2017. Estradiol patches are associated with local skin reactions and such as irritation in 14.2% of individuals (with reservoir patches), mild-to-moderate erythema (redness) in 50 to 60% of individuals, and allergic reactions due to cutaneous sensitization. Up to 5% of people using reservoir patches may discontinue therapy due to skin reactions. Visible adhesive residues are also often left by estradiol patches following their removal. Transdermal estradiol gel can serve as an alternative to transdermal estradiol patches for individuals who experience intolerable skin reactions with them. Estradiol patches should not be applied to the breast as this may result in high local levels of estradiol in the breasts and hence an increased likelihood of breast tenderness.
Both pathways rely on 5α-reductase, but in the androgen backdoor pathway, this enzyme acts on C21 steroids (pregnanes), initiating a series of chemical reactions that eventually lead to dihydrotestosterone production. In contrast, in the canonical pathway, 5α-reductase targets the 4,5-double bond in testosterone, producing dihydrotestosterone directly. The backdoor pathway was initially described as a biosynthetic route where 5α-reduction of 17α-hydroxyprogesterone ultimately leads to dihydrotestosterone. Since then, several other pathways have been discovered that lead to 11-oxygenated androgens which are also physiologically significant.
And some organelles also project extensions such as stromules from plastids in plant cells, peroxules from peroxisomes, and matrixules from mitochondria. Most distinct cell types arise from a single totipotent cell, called a zygote, that differentiates into hundreds of different cell types during the course of development. Differentiation of cells is driven by different environmental cues (such as cell–cell interaction) and intrinsic differences (such as those caused by the uneven distribution of molecules during division). Eukaryotic cell types include those that make up animals, plants, fungi, algae, and protists. All of which have many different species and cell differences. A separate grouping of animals and fungi are known as opisthokonts.
J. Lyons & Co. was a British restaurant chain store, food manufacturing, and hotel conglomerate founded in 1884 by Joseph Lyons and his brothers in law, Isidore and Montague Gluckstein. Lyons' first teashop opened in Piccadilly, London in 1894, and from 1909 they developed into a chain of teashops, with the firm becoming a staple of the High Street in the UK. At its peak the chain numbered around 200 cafes. The teashops provided for tea and coffee, with food choices consisting of hot dishes and sweets, cold dishes and sweets, and buns, cakes and rolls. Making their first cakes and pastries in 1894, several Lyons cake products are still available on grocers' shelves, including Lyons' treacle tart, Lyons' Bakewell tart, Lyons' Battenberg, and Lyons' trifle sponges, which are sold by Premier Foods. The company is also known for its pioneering use of computers in the office.
Sources: en.wikipedia.org
== Semantics of changing care: why "flexible" is replacing "intensive" therapy == Over the last two decades, the evidence that better glycemic control (i.e., keeping blood glucose and HbA1c levels as close to normal as possible) reduces the rates of many complications of diabetes has become overwhelming. As a result, diabetes specialists have expended increasing effort to help most people with diabetes achieve blood glucose levels as close to normal as achievable. It takes about the same amount of effort to achieve good glycemic control with a traditional two or three injection regimen as it does with flexible therapy: frequent glucose monitoring, attention to timing and amounts of meals. Many diabetes specialists no longer think of flexible insulin therapy as "intensive" or "special" treatment for a select group of patients but simply as standard care for most patients with type 1 diabetes.
Profilin binds to monomeric actin thereby occupying an actin-actin contact site; in effect, profilin sequesters actin from the pool of polymerizable actin monomers. However, profilin also catalyzes the exchange of actin-bound ADP to ATP thereby converting poorly polymerizing ADP-actin monomers into readily polymerizing ATP-actin monomers. On top of that, profilin has a higher affinity for ATP- than for ADP-actin monomers. Thus in a mixture of actin, profilin, and nucleotides (ADP and ATP), actin will polymerize to a certain extent, which may be estimated by the law of mass action. Profilin-actin complexes are fed into growing actin polymers by proteins such as formin, Wiskott-Aldrich syndrome protein and Vasodilator-stimulated phosphoprotein which contain proline-rich FH1-domains. This mode of stimulated actin polymerization is much faster than unaided polymerization. Profilin is essential for this mode of polymerization because it recruits the actin monomers to the proline-rich proteins. Profilin binds some variants of membrane phospholipids (phosphatidylinositol (4,5)-bisphosphate and inositol trisphosphate). The function of this interaction is the sequestration of profilin in an "inactive" form, from where it can be released by action of the enzyme phospholipase C. Profilin negatively regulates PI(3,4)P2 limiting recruitment of lamellipodia to the leading edge of the cell. Profilin is one of the most abundant actin monomer binders, but proteins such as CAP and (in mammals) thymosin β4 have some functional overlaps with profilin.
== Function == The target of C5 convertase is complement protein C5. C5 is a two-chain (α, β) plasma glycoprotein (Mr = 196,000). C5 and C3 have similar structure. However, C5 does not appear to contain the internal thiol ester group reported for C3 and C4. C5 has relatively few disulfide bonds. There are three disulfide bonds in C5a, the α-chain has 15 half-Cystines, and the β-chain has only 6 half-Cystines. This comparatively low level of stabilizing disulfide bridges may provide a partial explanation for the irreversible conformational change imparted on C5 after cleavage to C5a and C5b. In addition, the relatively low number of disulfide bonds could account for instability of C5 when exposed to chaotropic agents such as potassium thiocyanate. Electron micrographs of negatively stained C5 indicate that the protein is irregular in shape and contains several lobes. First of all, C5 has to bind to C3b fragment. The capacity to bind C3b is a stable feature of component C5, as C5b also has this binding capacity. The C5 convertase selectively cleaves an Arginyl-Leucine peptide bond at position 74-75 in the α-chain (Mr = 116,000) of C5. Research has shown that during the classical pathway of the complement system, an inactive A6 allotype of c4 completely stalls the molecules' ability to act as a c5 binding subunit1. This defect in C4A6 activity happens during the C5 binding step to the 4b and c3b complex. α´-chain (Mr, = 105,000) and the activation peptide, C5a, is formed, while β-chain (Mr = 80,000) remains unchanged.
Sources: en.wikipedia.org
Its legal status depends on the country and intended use. It is not an approved medicine in major jurisdictions. In sport, it is prohibited by anti-doping rules.
Laboratories typically use LC-MS/MS to detect SR9009 and related compounds in urine or blood. The method is sensitive but depends on sample collection timing. Confirmatory analysis follows quality-control procedures.
Solid material is generally kept cold, dry, and protected from light. Solutions are often stored in sealed containers at low temperature. Stability beyond recommended periods is not well documented.
Liquid chromatography with mass spectrometry is a common approach. Ultraviolet detection and nuclear magnetic resonance can support identification when suitable standards are available.