freeze-thaw is one of those subjects where the details matter more than the headlines. This page pulls together the background, the mechanisms, and the practical points readers ask about most.
Last reviewed on 2026-06-26. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
Storage recommendations for SR9009 reference material typically specify a freezer at -20 °C or lower, with protection from moisture and light. Repeated freeze-thaw cycles can degrade small molecules and introduce variability. Stock solutions in dimethyl sulfoxide are often aliquoted to avoid repeated handling. Stability studies may examine degradation under heat, humidity, and light exposure. The compound's thiophene and nitro groups can participate in reactions that alter analytical signals over time, so such changes affect quantitative results.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Typical storage temperature | -20 °C or lower | Desiccated and protected from light |
| Common analytical method | LC-MS/MS | Detects parent drug and metabolites |
| Solubility class | Lipophilic; soluble in organic solvents | Low aqueous solubility |
| Molecular weight | 437.94 g/mol | Calculated from reported formula |
| Synonyms | SR9009; REV-ERB agonist | Code name used in scientific literature |
Regulatory treatment of SR9009 varies by country and region. It is not approved as a pharmaceutical, and several jurisdictions restrict its sale for human consumption. Some authorities classify it as a research chemical, a prescription-only substance, or a prohibited performance-enhancing agent in sport. Purchasers may encounter certificates of analysis, but these documents do not guarantee identity, purity, or legality. In research settings, institutional safety reviews and controlled procurement help ensure that materials are handled under appropriate oversight. The absence of harmonized rules means that legal status can change and requires verification.
Analytical identification of SR9009 typically relies on liquid chromatography coupled with tandem mass spectrometry. In biological samples, researchers first separate the compound from matrix components using protein precipitation, liquid-liquid extraction, or solid-phase extraction. High-performance liquid chromatography with ultraviolet detection and nuclear magnetic resonance spectroscopy can support structural confirmation of reference materials. Because SR9009 is a small, relatively lipophilic molecule, reverse-phase columns and acidic mobile phases are common. Laboratories often include isotope-labeled internal standards to improve quantification and to correct for ion suppression.
Stability depends on physical form, temperature, light exposure, and solvent. Solid SR9009 is generally stored cold and dry, with protection from light to limit degradation. Dimethyl sulfoxide stocks are common for laboratory work, but repeated freeze-thaw cycles can reduce compound integrity. Aqueous solutions may be less stable than organic stocks, and the ethyl ester in the structure can be susceptible to hydrolysis under certain conditions. Researchers typically validate storage conditions and recheck purity before quantitative experiments, especially when using archived material.
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.
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.
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.
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 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.
=== Impurity === MDDMA is occasionally encountered as an impurity in MDMA which has been synthesized by methylation of MDA using methylating chemical reagents such as methyl iodide. An excess of reagent or a reaction temperature that is too high results in some double methylation of the amine nitrogen, yielding MDDMA as well as MDMA. The presence of MDDMA as an impurity can thus reveal which synthetic route was used to manufacture seized samples of MDMA.
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Each component in the sample interacts differently with the adsorbent material and the solvents, so their rates of elution are different. These different rates lead to analytical separation of the species in the fluid that flows out of the column (the eluate). The eluate enters a specific chromatography detector such as UV detectors, which produces a graph (the chromatogram). A chromatogram is a graph of detector signal intensity versus time or the volume of the mobile phase. If the analytes are well-separated, then the chromatogram would show well-separated peaks, one per analyte. Each analyte appears in its respective time (retention time) having area proportional to its amount. Chromatography can be described as a mass transfer process involving adsorption and/or partition. As mentioned, HPLC relies on pumps to pass a pressurized liquid and a sample mixture through a column filled with the adsorbent (the active component of the column). Some analytes may strongly attach to the adsorbent rather than the eluent, while other analytes may do the opposite. That is, the analytes may have different partition coefficients, leading to the separation of the analytes. The interaction between the analyte, the solid phase, and the liquid phase, are physical or chemically reversible, usually a combination of non-covalent interactions.
This interpretation remained controversial until NMR techniques demonstrated information transfer between hydrogen-bonded nuclei, a feat that would only be possible if the hydrogen bond contained some covalent character.
Mild to moderate hyperglycemia (typically 130–250 mg/dL, or 7–14 mmol/L) discovered before 25 years of age. However, anyone under 50 can develop MODY. A first-degree relative with a similar degree of diabetes. Absence of positive antibodies or other autoimmunity (e.g., thyroiditis) in patient and family. However, Urbanova et al. found that about one quarter of Central European MODY patients are positive for islet cell autoantibodies (GABA and IA2A). Their expression is transient but highly prevalent. The autoantibodies were found in patients with delayed diabetes onset, and in times of insufficient diabetes control. The islet cell autoantibodies are absent in MODY in at least some populations (Japanese, Britons). Persistence of a low insulin requirement (e.g., less than 0.5 u/kg/day) past the usual "honeymoon" period. Normal insulin levels (e.g. 2.6-24.9) Absence of obesity (although overweight or obese people can get MODY) or other problems associated with type 2 diabetes or metabolic syndrome (e.g., hypertension, hyperlipidemia, polycystic ovary syndrome). Insulin resistance very rarely happens. Cystic kidney disease in patient or close relatives. Non-transient neonatal diabetes, or apparent type 1 diabetes with onset before six months of age. Liver adenoma or hepatocellular carcinoma in MODY type 3 Renal cysts, rudimentary or bicornuate uterus, vaginal aplasia, absence of the vas deferens, epidymal cysts in MODY type 5 The diagnosis of MODY is confirmed by specific gene testing available through commercial laboratories.
Sources: en.wikipedia.org
Centromere protein A, also known as CENPA, is a protein which in humans is encoded by the CENPA gene. CENPA is a histone H3 variant which is the critical factor determining the kinetochore position(s) on each chromosome in most eukaryotes including humans.
"Service With the Speed of Sound" (1958) "Happy Eating" (1980s: on signs at many of the company's drive-ins) "America's Drive-In" (1987) "Faster and Better than Ever" (1988–1990) "No Place Hops like Sonic" (1990–1993) "Summer's Funner" (1993) "Drive-In for a Change" (1995–1997) "All Summer Long" (1997) "It's Sonic Good" (2003-2011) "Sonic's Got It, Others Don't" (2007) "Even Sweeter After Dark" (2009) "This is How You Sonic" (2011–2020) "Sonic Everywhere" (2016) "You Guys Wanna Hang Out Sometime" (2016) “This Is How We Sonic” (2020) "Mmm. Sonic." (2022) “Live Free, Eat Sonic” (2024)
== Reception == The American critic Thad Komorowski rated the episode two and a half out of five stars, noting that it is significantly less funny than its predecessor and its cruel nature serves as its worst aspect.
Christopher A. Lipinski is a medicinal chemist who is working at Pfizer, Inc. He is known for his "rule of five", an algorithm that predicts drug compounds that are likely to have oral activity. By the number of citations, he is the most cited author of some pharmacology journals: Journal of Pharmacological and Toxicological Methods, Advanced Drug Delivery Reviews, Drug Discovery Today: Technologies. Lipinski received his PhD from the University of California, Berkeley in 1968 in physical organic chemistry. The Advanced Drug Delivery Reviews article reporting his "rule of five" is one of the most cited publications in the journal's history. In 2006, he received an honorary law degree from the University of Dundee and he has won various awards, including being the Society for Biomolecular Sciences' winner of the 2006 SBS Achievement Award for Innovation in HTS.
=== Hydroxides === The oxides and hydroxides of neptunium are closely related to its ions. In general, Np hydroxides at various oxidation levels are less stable than the actinides before it on the periodic table such as thorium and uranium and more stable than those after it such as plutonium and americium. This phenomenon is because the stability of an ion increases as the ratio of atomic number to the radius of the ion increases. Thus actinides higher on the periodic table will more readily undergo hydrolysis. Neptunium(III) hydroxide is quite stable in acidic solutions and in environments that lack oxygen, but it will rapidly oxidize to the IV state in the presence of air. It is not soluble in water. Np(IV) hydroxides exist mainly as the electrically neutral Np(OH)4 and its mild solubility in water is not affected at all by the pH of the solution. This suggests that the other Np(IV) hydroxide, Np(OH)−5, does not have a significant presence. Because the Np(V) ion NpO+2 is very stable, it can only form a hydroxide in high acidity levels. When placed in a 0.1 M sodium perchlorate solution, it does not react significantly for a period of months, although a higher molar concentration of 3.0 M will result in it reacting to the solid hydroxide NpO2OH almost immediately. Np(VI) hydroxide is more reactive but it is still fairly stable in acidic solutions. It will form the compound NpO3·H2O in the presence of ozone under various carbon dioxide pressures. Np(VII) has not been well-studied and no neutral hydroxides have been reported. It probably exists mostly as [NpO4(OH)2]3−.
Sources: en.wikipedia.org
Liquid chromatography-tandem mass spectrometry is a common approach. It can detect the parent compound and its metabolites in biological matrices.
Research samples are typically kept frozen, desiccated, and protected from light. Stock solutions are often aliquoted to reduce freeze-thaw cycles.
High-performance liquid chromatography and nuclear magnetic resonance are standard for purity and identity. Mass spectrometry confirms molecular weight.
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.