A practical reference on freeze-thaw: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
This page was last updated on 2026-01-11 and is reviewed periodically as new material appears.
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.
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.
Analytical identification and purity assessment often use high-performance liquid chromatography with ultraviolet detection or mass spectrometry. Liquid chromatography–tandem mass spectrometry is used to detect and quantify SR9009 in biological matrices, including urine and blood, for anti-doping or pharmacokinetic studies. Nuclear magnetic resonance spectroscopy can confirm molecular structure. Stability depends on form and storage: the solid is generally more stable than solutions, and repeated freeze–thaw cycles may degrade samples. Purity is typically reported as a percentage from a certificate of analysis.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C20H24ClN3O4S | Derived from published structure. |
| Molecular weight | 437.94 g/mol | Calculated value. |
| Appearance | White to off-white solid | Typical for purified research samples. |
| Solubility | DMSO, ethanol; low in water | Class: poorly water-soluble. |
| Typical storage | -20 °C, desiccated, protected from light | Limits degradation. |
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.
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.
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.
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.
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.
1H, the most commonly used spin-1/2 nucleus in NMR investigations, has been studied using many forms of NMR. Hydrogen is highly abundant, especially in biological systems. It is the nucleus providing the strongest NMR signal (apart from 3H, which is not commonly used due to its instability and radioactivity). Proton NMR has a narrow chemical-shift range but gives sharp signals in solution state. Fast acquisition of quantitative spectra (with peak integrals in stoichiometric ratios) is possible due to short relaxation time. The 1H nucleus has provided the sole diagnostic signal for clinical magnetic resonance imaging (MRI). 2H, a spin-1 nucleus, is commonly utilized to provide a signal-free medium in the form of deuterated solvents for proton NMR, to avoid signal interference from hydrogen-containing solvents in measurement of 1H NMR of solutes. It is also used in determining the behavior of lipids in lipid membranes and other solids or liquid crystals as it is a relatively non-perturbing label which can selectively replace 1H. Alternatively, 2H can be detected in media specially labeled with 2H. Deuterium resonance is commonly used in high-resolution NMR spectroscopy to monitor drift of the magnetic field strength (lock) and to monitor the homogeneity of the external magnetic field. 3He is very sensitive to NMR. It exists at a very low concentration in natural helium and can be purified from 4He. It is used mainly in studies of endohedral fullerenes, where its chemical inertness is beneficial to ascertaining the structure of the entrapping fullerene.
=== Metabolism, recycling and excretion === Cholesterol is susceptible to oxidation and easily forms oxygenated derivatives called oxysterols. These can be formed by three different mechanisms: autoxidation, secondary oxidation to lipid peroxidation, and cholesterol-metabolizing enzyme oxidation. A great interest in oxysterols arose when they were shown to exert inhibitory actions on cholesterol biosynthesis. This finding became known as the "oxysterol hypothesis". Additional roles for oxysterols in human physiology include their participation in bile acid biosynthesis, function as transport forms of cholesterol, and regulation of gene transcription. In biochemical experiments, radiolabelled forms of cholesterol, such as tritiated-cholesterol, are used. These derivatives undergo degradation upon storage, and it is essential to purify cholesterol prior to use. Cholesterol can be purified using small Sephadex LH-20 columns. Cholesterol is oxidized by the liver into a variety of bile acids. These, in turn, are conjugated with glycine, taurine, glucuronic acid, or sulfate. A mixture of conjugated and nonconjugated bile acids, along with cholesterol itself, is excreted from the liver into the bile. Approximately 95% of the bile acids are reabsorbed from the intestines, and the remainder are lost in the feces. The excretion and reabsorption of bile acids forms the basis of the enterohepatic circulation, which is essential for the digestion and absorption of dietary fats.
Contrasting this, stochastic methodologies like Gibbs Sampling initiate motif discovery with random motif position assignments, iteratively refining the predictions. This probabilistic framework adeptly captures the inherent uncertainty associated with motif discovery. Advanced Approach: Evolving further, advanced motif discovery embraces sophisticated techniques, with Bayesian modeling taking center stage. LOGOS and BaMM, exemplifying this cohort, intricately weave Bayesian approaches and Markov models into their fabric for motif identification. The incorporation of Bayesian clustering methods enhances the probabilistic foundation, providing a holistic framework for pattern recognition in DNA sequences. Nature-Inspired and Heuristic Algorithms: A distinct category unfolds, wherein algorithms draw inspiration from the biological realm. Genetic Algorithms (GA), epitomized by FMGA and MDGA, navigate motif search through genetic operators and specialized strategies. Harnessing swarm intelligence principles, Particle Swarm Optimization (PSO), Artificial Bee Colony (ABC) algorithms, and Cuckoo Search (CS) algorithms, featured in GAEM, GARP, and MACS, venture into pheromone-based exploration. These algorithms, mirroring nature's adaptability and cooperative dynamics, serve as avant-garde strategies for motif identification. The synthesis of heuristic techniques in hybrid approaches underscores the adaptability of these algorithms in the intricate domain of motif discovery.
Sources: en.wikipedia.org
== Diagnosis == Hirsutism is a clinical diagnosis of excessive androgenic, terminal hair growth. A complete physical evaluation should be done prior to initiating more extensive studies, the examiner should differentiate between widespread body hair increase and male pattern virilization. One method of evaluating hirsutism is the Ferriman-Gallwey Score which gives a score based on the amount and location of hair growth. The Ferriman-Gallwey Score has various cutoffs due to variable expressivity of hair growth based on ethnic background. Diagnosis of patients with even mild hirsutism should include assessment of ovulation and ovarian ultrasound, due to the high prevalence of polyendocrine metabolic ovarian syndrome (PMOS), as well as 17α-hydroxyprogesterone (because of the possibility of finding non-classic 21-hydroxylase deficiency). People with hirsutism may present with an elevated serum dehydroepiandrosterone sulfate (DHEA-S) level, however, additional imaging is required to discriminate between malignant and benign etiologies of adrenal hyperandrogenism. Levels greater than 700 μg/dL are indicative of adrenal gland dysfunction, particularly congenital adrenal hyperplasia due to 21-hydroxylase deficiency. However, PMOS and idiopathic hirsutism make up 90% of cases.
== Deans or heads == The policy of the VCA has always been to enrol only those students who demonstrate the talent and dedication essential for courses as practising artists and performers. Similarly, members of the academic staff, including the director and the dean of each school, have themselves been accomplished and practising artists.
== Feeding == The mouth of the Hydra is surrounded by tentacles. When feeding, Hydra extend their body to maximum length and then slowly extend their tentacles. The tentacles of Hydra are extensible and can be four to five times the length of the body. To search for prey, Hydra extends its tentacles and slowly maneuvers them, waiting for contact. Upon contact with a prey, the stenoteles discharges neurotoxins; the desmonemes on the tentacle (nematocysts) also discharge threads that coil around the prey. Most of the tentacles join in the attack within 30 seconds. Within two minutes, the tentacles move the prey into the open mouth aperture. Within ten minutes, the prey is engulfed and digestion commences. A Hydra, with a column length of approximately 3–30 mm when extended and a width of about 1 mm, can stretch its body wall to digest prey more than twice its size. After 2–3 days, the indigestible remains will be discharged through the mouth aperture via contractions.The Hydra's mouth is not permanent: When the Hydra closes its mouth, the cells surrounding the open mouth fuse together. These joints are then broken when the Hydra feeds again.
Sources: en.wikipedia.org
SR9009 is a synthetic REV-ERB agonist used in laboratory research. It is not an approved drug, and its effects in humans are not well characterized. It is often sold as a research chemical under the name Stenabolic.
No. SR9009 targets the nuclear receptors REV-ERBα and REV-ERBβ, not the androgen receptor. This mechanism differs from selective androgen receptor modulators and from exercise mimetics that act on PPARδ.
Published evidence is mainly preclinical, using cell cultures and animal models. Controlled human trials are not well documented in the public literature. Claims about human performance or health effects therefore remain unsupported by robust clinical data.
Legality depends on the country and the intended use. In many places it is sold as a research chemical, but sports and medicine regulations restrict it.