A practical reference on reference standard: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
Reviewed 2026-01-24. Anything still debated is marked as such rather than presented as settled.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Appearance | White to off-white powder | Common supplier description |
| Solubility | Soluble in DMSO and ethanol | Low solubility in water |
| Typical storage | −20 °C, desiccated, dark | For research samples |
| Analytical method | LC-MS/MS | Used for detection and quantification |
| Regulatory status | Prohibited in sport | WADA metabolic modulator class |
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 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.
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.
Scientific discussion of SR9009 often separates animal evidence from human anecdote. Rodent studies provide controlled data on endurance, metabolism, and gene expression, but they use specific strains, doses, and treatment durations. Human reports are mostly uncontrolled and cannot establish cause and effect. Open questions include oral bioavailability, tissue distribution, metabolic stability, and long-term effects. Review articles generally call for more rigorous pharmacokinetic and safety research before any clinical use could be considered.
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.
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.
retinal + NAD+ + H2O → retinoic acid + NADH + H+ Retinoic acid is actively transported into the cell nucleus by CRABp2 where it regulates thousands of genes by binding directly to gene targets via retinoic acid receptors. In addition to retinol, retinal and retinoic acid, there are plant-, fungi- or bacteria-sourced carotenoids which can be metabolized to retinol, and are thus vitamin A vitamers. There are also what are referred to as 2nd, 3rd and 4th generation retinoids which are not considered vitamin A vitamers because they cannot be converted to retinol, retinal or all-trans-retinoic acid. Some are prescription drugs, oral or topical, for various indications. Examples are etretinate, acitretin, adapalene, bexarotene, tazarotene and trifarotene.
=== Obesity and diabetes === TGF-β/SMAD3 signaling pathway is important in regulating glucose and energy homeostasis and might play a role in diabetic nephropathy. As noted above in the section about macrophages, loss of TGF-β signaling in obesity is one contributor to the inflammatory milieu generated in the case of obesity.
=== Doping in sport === LGD-4033 is on the World Anti-Doping Association (WADA) list of prohibited drugs and has been found in drug testing samples of some athletes. Since at least June 2015, LGD-4033 has been available via the internet. In that month, German scientists proposed a new test to detect its metabolites present in human urine, and suggested an expansion of the WADA regime. LGD-4033 has been found in WADA samples and in racehorses as well.
Sources: en.wikipedia.org
In 2001, the World Health Organization reported that data from Kosovo was inconclusive and called for further studies. That same year, governments of several European countries, particularly Italy, reported an increase in illnesses and developments of cancers among veterans that served in Balkan peacekeeping missions. A 2003 study by the United Nations Environment Programme (UNEP) in Bosnia and Herzegovina stated that low levels of contaminant were found in drinking water and air particulate at DU penetrator impact points. The levels were stated as not a cause for alarm. Yet, Pekka Haavisto, chairman of the UNEP DU projects stated, "The findings of this study stress again the importance of appropriate clean-up and civil protection measures in a post-conflict situation." A team of Italian scientists from the University of Siena reported in 2005 that, although DU was "clearly" added to the soil in the study area, "the phenomenon was very limited spatially and the total uranium concentrations fell within the natural range of the element in soils.
On 15 May 2015, the FDA issued a warning that certain SGLT2 diabetes drugs, including canagliflozin, may lead to ketoacidosis, a condition where the body produces higher levels of ketone bodies. The FDA is continuing to investigate the issue, and cautions that patients should not stop taking canagliflozin without first talking to their doctor. On 10 September 2015, the FDA issued a drug safety communication for canagliflozin to address risks for bone fracture and decreased bone density. A label warning for fractures was already included in the Adverse Reactions section; however, the FDA made the addition to the Warnings and Precautions section to reflect new information from a placebo study. They advised that health care professionals should consider fracture risk factors before prescribing canagliflozin, and patients should disclose any bone fracture risk factors to their doctors, but that patients should not stop taking the medication without first talking to their doctor. On 4 December 2015, the FDA issued another safety communication for SGLT2 inhibitors, indicating that it would require new warnings to be added to the canagliflozin label about elevated blood acid levels and urinary tract infections. In June 2016, the FDA strengthened the warning about the risk of acute kidney injury for the type 2 diabetes medicines canagliflozin (Invokana, Invokamet) and dapagliflozin (Farxiga, Xigduo XR).
== Production == Produced mainly in parts of the world where pineapples are grown, such as Thailand or Malaysia, bromelain is extracted from the peel, stem, leaves or waste of the pineapple plant after processing the fruit for juice or other purposes. The starting material is blended and pressed through a filter to obtain a supernatant liquid containing the soluble bromelain enzyme. Further processing includes purification and concentration of the enzyme.
Established in 1889, the University of Cincinnati College of Nursing was the first school to offer a baccalaureate degree in nursing in 1916. In 1942, the college became a charter member of the National League for Nursing. In 2002 the college was the first nursing school to offer cooperative education in addition to clinical time, and in 2010 it began a Doctorate of Nursing Practice. Successes include awarding over $1.0 million in scholarships and graduate assistantship stipends for the 2008 – 2009 academic year, ranking in the top 10 percent of American nursing programs, receiving over $2.6 million in extramural research awards during the 2009 fiscal year and developing partnerships with over 300 clinical sites. In 1982, the college was one of eleven nursing schools that received the Robert Wood Johnson Teaching Nursing Home Project Grant. In 1987, IBM chose the college as one of fifteen to develop computer-assisted interactive video for health sciences. A nursing doctoral program and nurse anesthetist master's program were established in 1990. In 1992, the college established a joint master's degree (MSN/MBA) with the Lindner College of Business.
Sources: en.wikipedia.org
== Tuftsin analogues == Tuftsin sequence appears in all four classes of IgG. However, only leukokinin, a small fraction of IgG1, displays tuftsin activity. Tuftsin occurs in guinea pig IgG2 exactly in the same position. The mouse IgG1 analogue is a tetrapeptide Thr-Gln-Pro-Arg (TQPR) at the same place, one base change at the first base of the triplet code. Tuftsin sequence appears in residues 9-12 from the amino terminal of p12 protein of Rauscher murine leukemia virus. The tetrapeptide Thr-Arg-Pro-Lys (TRPK) is in the influenza hemagglutinin virus protein, residues 214–217. The canine analogue is the tetrapeptide Thr-Lys-Pro-Lys (TKPK). The peptide Thr-Arg-Pro-Arg (TRPR) is a biologically active pancreatic polypeptide 32–35 with gastrointestinal functions. Thr-Arg-Pro-Arg, Thr-Lys-Pro-Lys, Thr-Arg-Pro-Lys are as active as Thr-Lys-Pro-Arg. Thr-Lys-Pro-Pro-Arg (TKPPR) is a potent inhibitor. Lys-Pro-Pro-Arg (KPPR) is also an inhibitor of phagocytosis, superoxide anion production and chemotaxis both human and rat PMN leukocytes and monocytes. Tyr-Lys-Pro exert considerable regulatory effect on several macrophage functions including: phagocytosis, cell locomotion, superoxide anion production, IgE-dependent cellular cytotoxicity, β-glycuronidase release, and IL-1 production. Selank is an elongated version of tuftsin with a Pro-Gly-Pro appended, i.e. Thr-Lys-Pro-Arg-Pro-Gly-Pro (TKPRPGP). It has been claimed to have anti-anxiety and nootropic effects and is used in Russia and other former Soviet bloc countries.
=== Hierarchical structure === While the secondary structures are determined by energy state and hydrogen bonds formed between amino acids, hierarchical structures are determined by the hydrophobicity of the peptide. Exon 1 encoded peptide is mainly hydrophilic, and is more extended when immersed in water. In contrast, exon 3 encoded peptide contains both hydrophobic and hydrophilic blocks, suggesting the formation of micelles, where the hydrophobic block will cluster on the inside with the hydrophilic portion surrounding it. Thus, a single complete resilin protein, when immersed in water, takes on the structure in which exon 1 encoded segment extends out from the micelle exon 3 encoded peptide forms. Once resilin is transferred to the outside of the cell, their exon 2 encoded peptides, the chitin binding segments, bind to chitin. Meanwhile, di- or tri-tyrosine crosslinking is formed by oxidative coupling, mediated by peroxidase, between tyrosine residuals. Like other elastomeric proteins, the degree of cross linking in resilin is low, which ensures the low stiffness and high resilience. Cross linked peptides encoded by exon 1 have a resilience greater than 93%, while that encoded by exon 3 has a resilience of 86%. In addition, natural resilin has a resilience of 92%, similar to that of exon 1, suggesting again that exon 1 may play a more important role in the elastic property of resilin.
The Murchison meteorite is a meteorite that fell in Australia in 1969 near Murchison, Victoria. It belongs to the carbonaceous chondrite class, a group of meteorites rich in organic compounds. Due to its mass (over 100 kg or 220 lb) and the fact that it was an observed fall, the Murchison meteorite is one of the most studied of all meteorites. In January 2020, cosmochemists reported that the oldest material found on Earth to date are the silicon carbide particles from the Murchison meteorite, which have been determined to be 7 billion years old, about 2.5 billion years older than the 4.54-billion-year age of the Earth and the Solar System. The published study noted that "dust lifetime estimates mainly rely on sophisticated theoretical models. These models, however, focus on the more common small dust grains and are based on assumptions with large uncertainties."
Sources: en.wikipedia.org
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.
Detection commonly uses liquid chromatography–tandem mass spectrometry. This method can identify the compound in urine or blood at low concentrations.
Typical guidance is −20 °C, dry, and protected from light. Solutions should be aliquoted and limited freeze–thaw cycles should be used.
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.