If you have been reading about freeze-thaw 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 2025-08-17. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
SR9009 is frequently discussed in fitness and research-chemical contexts, yet it has no approved medical indication. Regulatory agencies have not authorized it for human use, and it is not a standard prescription drug. Some sports organizations list it as a prohibited substance because of its potential performance-enhancing properties. Published human data are sparse, so claims about its effects in people often rely on animal models or anecdotal reports. Quality and identity of online materials can vary widely.
SR9009 is a synthetic small molecule studied as a REV-ERB agonist. REV-ERBα and REV-ERBβ are nuclear receptors that help regulate circadian rhythms and metabolic gene expression. The compound was identified in academic screening efforts to find synthetic ligands for these receptors. In cell and animal studies, SR9009 alters transcription of genes involved in lipid and glucose metabolism, and it can shift circadian behavior. It is not an approved therapeutic agent.
| Property | Value | Notes |
|---|---|---|
| Common name | SR9009 | Also referred to as Stenabolic in non-scientific contexts. |
| Chemical class | Synthetic small molecule | Not a steroid or peptide hormone. |
| Receptor target | REV-ERBα and REV-ERBβ | Nuclear receptor agonist in preclinical studies. |
| Development status | Investigational | No approved human therapeutic indication. |
| Regulatory attention | Prohibited in sport | Listed by anti-doping authorities. |
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.
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.
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.
SR9009 is a synthetic small molecule studied as an agonist of REV-ERB nuclear receptors. REV-ERB alpha and REV-ERB beta help regulate circadian rhythms and metabolic gene expression. In laboratory research, SR9009 has been used to probe how these receptors affect skeletal muscle, liver, and adipose tissue. The compound was identified in academic drug-discovery work and is often described in scientific literature by its chemical name and research code. It is not an approved medicine, and human clinical data remain limited or absent.
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.
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.
=== Hapeville Dwarf House === Truett Cathy opened his first restaurant in 1946, The Dwarf Grill – later renamed the Dwarf House – in Hapeville, Georgia, and developed the pressure-cooked chicken breast sandwich there. At the original Chick-fil-A Dwarf Grill, there is also an extra small-sized front door in addition to the full-size entrances. The original Dwarf House in Hapeville, Georgia. It has a larger dine-in menu than the other Dwarf House locations, and an animated seven-dwarf display is at the back of the restaurant.
=== Space exploration === A direct search for life in Europa's ocean would today be prohibitively expensive. Impacts on Europa give us an easier way to look for evidence of life there. Every time a major impact occurs on Europa, a vast quantity of water is splashed from the ocean into the space around Jupiter. Some of the water evaporates, and some condenses into snow. Creatures living in the water far enough from the impact have a chance of being splashed intact into space and quickly freeze-dried. Therefore, an easy way to look for evidence of life in Europa's ocean is to look for freeze-dried fish in the ring of space debris orbiting Jupiter. Freeze-dried fish orbiting Jupiter is a fanciful notion, but nature in the biological realm has a tendency to be fanciful. Nature is usually more imaginative than we are. ...To have the best chance of success, we should keep our eyes open for all possibilities.
===== MeSH D08.811.464.267 – carbon-sulfur ligases (EC 6.2) ===== MeSH D08.811.464.267.500 – coenzyme a ligases MeSH D08.811.464.267.500.200 – acetate-coa ligase MeSH D08.811.464.267.500.600 – succinate-coa ligases
In addition to structures, nuclear magnetic resonance can yield information on the dynamics of various parts of the protein. This usually involves measuring relaxation times such as T1 and T2 to determine order parameters, correlation times, and chemical exchange rates. NMR relaxation is a consequence of local fluctuating magnetic fields within a molecule. Local fluctuating magnetic fields are generated by molecular motions. In this way, measurements of relaxation times can provide information of motions within a molecule on the atomic level. In NMR studies of protein dynamics, the nitrogen-15 isotope is the preferred nucleus to study because its relaxation times are relatively simple to relate to molecular motions. This, however, requires isotope labeling of the protein. The T1 and T2 relaxation times can be measured using various types of HSQC-based experiments. The types of motions that can be detected are motions that occur on a time-scale ranging from about 10 picoseconds to about 10 nanoseconds. In addition, slower motions, which take place on a time-scale ranging from about 10 microseconds to 100 milliseconds, can also be studied. However, since nitrogen atoms are found mainly in the backbone of a protein, the results mainly reflect the motions of the backbone, which is the most rigid part of a protein molecule. Thus, the results obtained from nitrogen-15 relaxation measurements may not be representative of the whole protein.
To achieve this goal, they demonstrated that solution-processed perovskites can spontaneously form submicrometre-scale crystal platelets, which can efficiently extract light from the device. These perovskites are formed via the introduction of amino acid additives into the perovskite precursor solutions. In addition, their method is able to passivate perovskite surface defects and reduce nonradiative recombination. Therefore, by improving the light outcoupling and reducing nonradiative losses, Cao and his colleagues successfully achieved PLED with EQE up to 20.7%. Lin and his colleague used a different approach to generate high EQE. Instead of modifying the microstructure of perovskite layer, they chose to adopt a new strategy for managing the compositional distribution in the device—an approach that simultaneously provides high luminescence and balanced charge injection. In other words, they still used flat emissive layer, but tried to optimize the balance of electrons and holes injected into the perovskite, so as to make the most efficient use of the charge carriers. Moreover, in the perovskite layer, the crystals are perfectly enclosed by MABr additive (where MA is CH3NH3). The MABr shell passivates the nonradiative defects that would otherwise be present perovskite crystals, resulting in reduction of the nonradiative recombination. Therefore, by balancing charge injection and decreasing nonradiative losses, Lin and his colleagues developed PLED with EQE up to 20.3%.
Sources: en.wikipedia.org
== Applications == Scientific techniques, such as immunostaining, depend on chemical specificity. Immunostaining utilizes the chemical specificity of antibodies in order to detect a protein of interest at the cellular level. Another technique that relies on chemical specificity is Western blotting, which is utilized to detect a certain protein of interest in a tissue. This technique involves gel electrophoresis followed by transferring of the sample onto a membrane which is stained by antibodies. Antibodies are specific to the target protein of interest, and will contain a fluorescent tag signaling the presence of the researcher's protein of interest.
Lysozyme PEGylation is the covalent attachment of Polyethylene glycol (PEG) to Lysozyme, which is one of the most widely investigated PEGylated proteins. The PEGylation of proteins has become a common practice of modern therapeutic drugs, as the process is capable of enhancing solubility, thermal stability, enzymatic degradation resistance, and serum half-life of the proteins of interest. Lysozyme, as a natural bactericidal enzyme, lyses the cell wall of various gram-positive bacteria and offers protection against microbial infections. Lysozyme has six lysine residues which are accessible for PEGylation reactions. Thus, the PEGylation of lysozyme, or lysozyme PEGylation, can be a good model system for the PEGylation of other proteins with enzymatic activities by showing the enhancement of its physical and thermal stability while retaining its activity. Previous works on lysozyme PEGylation showed various chromatographic schemes in order to purify PEGylated lysozyme, which included ion exchange chromatography, hydrophobic interaction chromatography, and size-exclusion chromatography (fast protein liquid chromatography), and proved its stable conformation via circular dichroism and improved thermal stability by enzymatic activity assays, SDS-PAGE, and size-exclusion chromatography (high-performance liquid chromatography).
==== Pat Farrell's Alpha-Angle Freeze Mark ==== A specialized brand system is required to mark many animals such that each can be individually identified. Arabic numerals are difficult to brand much smaller than 4 inches (10 cm) tall. Further, conventional numbers can be altered, with a branded "3" easily turned into an "8," potentially shifting apparent ownership of the horse. It is also inconvenient to carry a dozen or more unique brands into the field if animals must be branded there.
OD600 (Also written as O.D. 600, D600, o.d. 600, OD600) is an abbreviation indicating the optical density of a sample measured at a wavelength of 600 nm in 1 cm light path (unless otherwise stated). It is a commonly used in microbiology for estimating the concentration of bacteria or other cells in a liquid as the 600 nm wavelength does little to damage or hinder their growth. OD600 is a type of turbidity measurement. Since optical density in case of OD600 measurements results from light scattering by particles (cells) rather than absorption, size and shape as well as dead cells and debris of a cell may add to light dissipating. Distinctive cell types that are at densities of the same level (eg. cell/mL), may, therefore, show varying values OD600, when estimated on a similar instrument. For turbid samples such as cell cultures, the major contributor for the optical density measured is light scattering and not the result of molecular absorption following the Beer-Lambert Law. The measurements are therefore depending on the optical setup of the spectrophotometer (distance between the cell holder and instrument exit slit, monochromator optics, slit geometry, etc.), different instrument types will most likely tend to give different OD600 readings for the same turbid sample. Measuring the change of the OD600 as a function of time (e.g. measuring of the growth curve) may indicate the growth phase of cultured cell population, i.e. whether it is in the lag phase, log phase, or stationary phase.
Sources: en.wikipedia.org
It is a synthetic compound studied as an agonist of REV-ERB nuclear receptors. It is not an approved medicine and has mainly been examined in laboratory and animal research.
No. It is a small molecule that binds nuclear receptors involved in circadian regulation. Its classification differs from anabolic steroids or peptide hormones.
Published human clinical trial data are lacking. Most safety and activity information comes from preclinical models, so effects in people remain uncertain.
SR9009 is a synthetic compound investigated as an agonist of the nuclear receptors REV-ERBα and REV-ERBβ. It is used in preclinical research on circadian rhythm and metabolism. It is not an approved drug.