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 2025-08-18 and is reviewed periodically as new material appears.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Appearance | White to off-white powder | Typical for research-grade material |
| Solubility | Soluble in DMSO and ethanol; low aqueous solubility | Organic stock solutions are common |
| Typical storage temperature | -20 °C or lower | Protect from light and moisture |
| Common analytical method | LC-MS/MS | Used for detection and confirmation |
| Common synonyms | SR9009; Stenabolic | Stenabolic is an informal name |
Research interest in SR9009 grew from studies showing improved running endurance in mice after short treatment periods. Those experiments linked the compound to increased mitochondrial content and fatty acid oxidation in muscle, but the findings come from animal models and specific dosing schedules. Independent replication has been limited, and the pathways connecting REV-ERB activation to exercise performance are still being mapped. Whether similar responses occur in humans is an open question.
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 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.
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.
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.
In molecular biology, the BtpA protein family is a family of proteins which includes BtpA. BtpA appears to play a role in the stabilisation of photosystem I. It is an extrinsic membrane protein located on the cytoplasmic side of the thylakoid membrane. Homologs of BtpA are found in the Thermoproteota and "Euryarchaeota", where their function remains unknown. The Ycf4 protein is firmly associated with the thylakoid membrane, presumably through a transmembrane domain. Ycf4 co-fractionates with a protein complex larger than PSI upon sucrose density gradient centrifugation of solubilised thylakoids. The Ycf3 protein is loosely associated with the thylakoid membrane and can be released from the membrane with sodium carbonate. This suggests that Ycf3 is not part of a stable complex and that it probably interacts transiently with its partners. Ycf3 contains a number of tetratricopeptide repeats (TPR); TPR is a structural motif present in a wide range of proteins, which mediates protein-protein interactions.
Back pressure is the term used for the hydraulic pressure required to create a flow through a chromatography column in high-performance liquid chromatography, the term deriving from the fact that it is generated by the resistance of the column, and exerts its influence backwards on the pump that must supply the flow. Back-pressure is a useful diagnostic feature of problems with the chromatography column. Rapid chromatography is favoured by columns packed with very small particles, which create high back-pressures. Column designers use "kinetic plots" to show the performance of a column at a constant back-pressure, usually selected as the maximum that a system's pump can reliably produce. Exhaust pulse pressure charging Expansion chamber Scalar quantity
In 1979 Zaffaroni was awarded the Chemical Pioneer Award by the American Institute of Chemists In 1995, he received the National Medal of Technology from President Bill Clinton for his contributions to the pharmaceutical and biotechnology industries. In 2004, he was one of the recipients of the Winthrop-Sears Medal from the Chemical Heritage Foundation and The Chemists’ Club, with George Rosenkranz. In 2005 he received the Bower Award for Business Leadership from the Franklin Institute for his creation of new biochemical processes and drug delivery technologies. In 2005 he was awarded the Gregory Pincus Award from the Worcester Foundation. In 2006, he received the Biotechnology Heritage Award, from the Biotechnology Industry Organization (BIO) and the Chemical Heritage Foundation.
A rare development is amyloid purpura, a susceptibility to bleeding with bruising around the eyes, termed "raccoon-eyes". Amyloid purpura is caused by amyloid deposition in the blood vessels and reduced activity of thrombin and factor X, two clotting proteins that lose their function after binding with amyloid. Amyloid deposits in tissue can cause enlargement of structures. Twenty percent of people with AL amyloidosis have an enlarged tongue, that can lead to obstructive sleep apnea, difficulty swallowing, and altered taste. Tongue enlargement does not occur in ATTR or AA amyloidosis. Deposition of amyloid in the throat can cause hoarseness.
Arginylglycylaspartic acid (RGD) is the most common peptide motif responsible for cell adhesion to the extracellular matrix (ECM), found in species ranging from Drosophila to humans. Cell adhesion proteins called integrins recognize and bind to this sequence, which is found within many matrix proteins, including fibronectin, fibrinogen, vitronectin, osteopontin, and several other adhesive extracellular matrix proteins. The discovery of RGD and elucidation of how RGD binds to integrins has led to the development of a number of drugs and diagnostics, while the peptide itself is used ubiquitously in bioengineering. Depending on the application and the integrin targeted, RGD can be chemically modified or replaced by a similar peptide which promotes cell adhesion.
Sources: en.wikipedia.org
Ethane-1,2-dithiol, also known as EDT, is a colorless liquid with the formula C2H4(SH)2. It has a very characteristic odor which is compared by many people to rotten cabbage. It is a common building block in organic synthesis and an excellent ligand for metal ions. Ethane-1,2-dithiol is made commercially by the reaction of 1,2-dichloroethane with aqueous sodium bisulfide. In the laboratory, it can also be prepared by the action of 1,2-dibromoethane on thiourea followed by hydrolysis. 1,2-Ethanedithiol is a weak acid, typical of alkyl thiols. In the presence of base and an alkylating agent, 1,2-ethanedithiol converts to thioethers: HS(CH2)2SH + 2 NR3 + 2 R'I → R'S(CH2)2SR' + 2 [R3NH]I Oxidation of 1,2-ethanedithiol gives a series of oligomers, including the cyclic bis(disulfide). As a 1,2-dithiol, this compound reacts with aldehydes and ketones to give 1,3-dithiolanes, which can be useful intermediates.
1-Ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC, EDAC or EDCI) is a water-soluble carbodiimide usually handled as the hydrochloride, which is a white solid. It is typically employed in the 4.0-6.0 pH range. It is generally used as a carboxyl activating agent for the coupling of primary amines to yield amide bonds. While other carbodiimides like dicyclohexylcarbodiimide (DCC) or diisopropylcarbodiimide (DIC) are also employed for this purpose, EDC has the advantage that the urea byproduct formed (often challenging to remove in the case of DCC or DIC) can be washed away from the amide product using dilute acid. Additionally, EDC can also be used to activate phosphate groups in order to form phosphomonoesters and phosphodiesters. Common uses for this carbodiimide include peptide synthesis, protein crosslinking to nucleic acids, but also in the preparation of immunoconjugates. EDC is often used in combination with N-hydroxysuccinimide (NHS) for the immobilisation of large biomolecules. Recent work has also used EDC to assess the structure state of uracil nucleobases in RNA.
C4H2N2O4 + GSH → C4H3N2O4• + GS• C4H3N2O4• + GSH → C4H4N2O4 + GS• C4H4N2O4 + O2 → C4H3N2O4• + O2•− + H+ C4H3N2O4• + O2 → C4H2N2O4 + O2•− + H+ Because it selectively kills the insulin-producing beta-cells found in the pancreas, alloxan is used to induce diabetes in laboratory animals. This occurs most likely because of selective uptake of the compound due to its structural similarity to glucose as well as the beta-cell's highly efficient uptake mechanism (GLUT2). In addition, alloxan has a high affinity to SH-containing cellular compounds and, as a result, reduces glutathione content. Furthermore, alloxan inhibits glucokinase, a SH-containing protein essential for insulin secretion induced by glucose. Most studies have shown that alloxan is not toxic to the human beta-cell, even in very high doses, probably because of differing glucose uptake mechanisms in humans and rodents. Alloxan is, however, toxic to the liver and the kidneys in high doses, as these are tissues where the GLUT2 transporter is expressed in humans. Streptozotocin
Ana María Muñoz Jauregui (born 1969, Lima) is a Peruvian pharmacist, biochemist and nutritionist. She has served as Rector and, since 2023, as the Vice Rector of research at San Ignacio de Loyola University (USIL). Muñoz has authored numerous publications and received national and international awards, such as silver, gold medals and semi-grand prize wins at the International KIWIE Award. Muñoz, was born in Lima, Peru. In 1996, she attended the National University of San Marcos (UNMSM), where she earned her pharmaceutical degree. While studying, she developed an interest in the field of nutrition. She earned a master's degree in biochemistry and nutrition, and earned a PhD in Pharmacy and Biochemistry from the National University of San Marcos (UNMSM) in 2006.
Sources: en.wikipedia.org
ABS-201 is an AI-designed monoclonal antibody against the prolactin receptor (PRLR) currently in Phase 1/2a clinical trial for the treatment of androgenic alopecia (pattern hair loss) and endometriosis. It is taken by subcutaneous injection. ABS-201 is a possible first-in-class drug with a novel mechanism of action in the potential treatment of hair loss. ABS-201 is under development by Absci. It is believed that ABS-201 works by activating dormant hair follicles and causing them to move from the telogen phase to the anagen phase. In human ex vivo scalp model studies, ABS-201 stimulated hair regrowth, prolonged anagen phase, blocked catagen phase, inhibited telogen effluvium, and blocked hair from losing color. ABS-201 has been found to produce robust hair regrowth as compared with minoxidil in mice and balding macaques. The clinical trial for ABS-201 is being overseen by prominent hair loss researcher Rodney Sinclair, one of the principal investigators in minoxidil clinical trials. The chemical structure of the drug does not yet appear to have been disclosed.
Network Science, Part 5: Solvent-Accessible Surfaces AREAIMOL is a command line tool in the CCP4 Program Suite for calculating ASA. NACCESS solvent accessible area calculations. FreeSASA Open source command line tool, C library and Python module for calculating ASA. Surface Racer Oleg Tsodikov's Surface Racer program. Solvent accessible and molecular surface area and average curvature calculation. Free for academic use. ASA.py — a Python-based implementation of the Shrake-Rupley algorithm. Michel Sanner's Molecular Surface – the fastest program to calculate the excluded surface. pov4grasp render molecular surfaces. Molecular Surface Package — Michael Connolly's program. Volume Voxelator — A web-based tool to generate excluded surfaces. ASV freeware Analytical calculation of the volume and surface of the union of n spheres (Monte-Carlo calculation also provided). Vorlume Computing Surface Area and Volume of a Family of 3D Balls. GetArea Calculate solvent accessible surface area of proteins online. ProMS ProMS - Protein Molecular Surface Calculator
The iron-containing co-factor is found tightly associated with the protein. It can be released upon denaturation with 2-mercaptoethanol or guanidine hydrochloride. Expression of the Hmd gene in E. coli without the co-factor results in an inactive holoenzyme. However, hydrogenase activity can be rescued by the addition of the iron-containing cofactor taken from denatured active enzyme. As mentioned, irradiation of the cofactor with UV light results in the loss of CO and Fe. In addition the 542 Da compound can be further degraded by a phosphodiesterase (which specifically cleaves phosphate bonds). Hydrolysis of the phosphate bonds generates the ribonucleotide guanosine monophosphate and a modified 2-pyridone. On the basis of spectroscopic characterization, Shima et al. have proposed a structure for this organic cofactor (minus the iron atom and CO molecules) as shown:
Sources: en.wikipedia.org
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.
Liquid chromatography with tandem mass spectrometry is widely used to detect and confirm SR9009 in laboratory samples. The technique offers high sensitivity and can distinguish the target compound from related substances. Nuclear magnetic resonance and ultraviolet detection may support identity and purity checks.
Online products labeled as SR9009 may vary in identity, purity, and actual content. Independent testing helps confirm that a sample matches its label and does not contain unexpected contaminants. This is important for reproducible research and for interpreting experimental results.
Liquid chromatography-tandem mass spectrometry is a common approach. It can detect the parent compound and its metabolites in biological matrices.