A practical reference on HPLC-MS: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
This page was last updated on 2026-02-28 and is reviewed periodically as new material appears.
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 developed as a REV-ERB agonist. It binds to REV-ERBα and REV-ERBβ, nuclear receptors that help regulate circadian rhythms and metabolic gene expression. In cell and animal studies, the compound alters lipid and glucose handling and influences skeletal muscle oxidative capacity. Its exact effects in humans remain largely uncharacterized because controlled clinical trials have not been reported. The molecule is frequently described in preclinical literature as a metabolic modulator.
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 frequently discussed alongside other REV-ERB ligands, including synthetic agonists and natural heme-related molecules. Its selectivity for REV-ERB over related nuclear receptors has been measured in binding and reporter assays, though off-target activity at higher concentrations is possible. The compound is prohibited in sport by the World Anti-Doping Agency, and it is not approved for any medical use in major jurisdictions. Products sold online may be labeled as research chemicals, and their identity and purity are not guaranteed by regulatory review.
SR9009 is a synthetic small molecule that acts on the nuclear receptors REV-ERBα and REV-ERBβ. These receptors are part of the circadian clock machinery and normally repress transcription of certain target genes. In laboratory research, SR9009 is used as a chemical tool to study how REV-ERB activity influences metabolism, inflammation, and daily biological rhythms. The compound is not an approved medicine, and its effects in humans remain largely uncharacterized. It is often described as an investigational agent rather than a therapeutic product.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C20H24ClN3O4S | Reported for the free base |
| Molecular weight | 437.9 g/mol | Calculated from the formula |
| Primary target | REV-ERBα and REV-ERBβ | Nuclear receptors involved in circadian regulation |
| Solubility | Soluble in DMSO and ethanol | Poorly soluble in water |
| Typical storage | -20 °C, desiccated | Protect from light and moisture |
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.
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.
=== As a host for intracellular pathogens === In their role as a phagocytic immune cell macrophages are responsible for engulfing pathogens to destroy them. Some pathogens subvert this process and instead live inside the macrophage. This provides an environment in which the pathogen is hidden from the immune system and allows it to replicate. Diseases with this type of behaviour include tuberculosis (caused by Mycobacterium tuberculosis) and leishmaniasis (caused by Leishmania species). In order to minimize the possibility of becoming the host of an intracellular bacteria, macrophages have evolved defense mechanisms such as induction of nitric oxide and reactive oxygen intermediates, which are toxic to microbes. Macrophages have also evolved the ability to restrict the microbe's nutrient supply and induce autophagy.
== Measuring the freeze point == Once antifreeze has been mixed with water and put into use, it periodically needs to be maintained. If engine coolant leaks, boils, or if the cooling system needs to be drained and refilled, the antifreeze's freeze protection will need to be considered. In other cases a vehicle may need to be operated in a colder environment, requiring more antifreeze and less water. Three methods are commonly employed to determine the freeze point of the solution by measuring the concentration:
=== Chalcogen === Serine, homoserine, O-methylhomoserine and O-ethylhomoserine possess a hydroxymethyl, hydroxyethyl, O-methylhydroxymethyl and O-methylhydroxyethyl side chain; whereas cysteine, homocysteine, methionine and ethionine possess the thiol equivalents. The selenol equivalents are selenocysteine, selenohomocysteine, selenomethionine and selenoethionine. Amino acids with the next chalcogen down are also found in nature: several species such as Aspergillus fumigatus, Aspergillus terreus, and Penicillium chrysogenum in the absence of sulfur are able to produce and incorporate into protein tellurocysteine and telluromethionine.
=== Early life: 1946–1966 === Bantu Stephen Biko was born on 18 December 1946, at his grandmother's house in Tarkastad, Cape Province (now the Eastern Cape). The third child of Mzingaye Mathew Biko and Alice 'Mamcete' Biko, he had an older sister, Bukelwa, an older brother, Khaya, and a younger sister, Nobandile. His parents had married in Whittlesea, where his father worked as a police officer. Mzingaye was transferred to Queenstown, Port Elizabeth, Fort Cox, and finally King William's Town, where he and Alice settled in Ginsberg township. This was a settlement of around 800 families, with every four families sharing a water supply and toilet. Both Africans and Coloured people lived in the township, where Xhosa, Afrikaans, and English were all spoken. After resigning from the police force, Mzingaye worked as a clerk in the King William's Town Native Affairs Office, while studying for a law degree by correspondence from the University of South Africa. Alice was employed first in domestic work for local white households, then as a cook at Grey Hospital in King William's Town. According to his sister, it was this observation of his mother's difficult working conditions that resulted in Biko's earliest politicisation.
The antigens are memorised by these cells so that subsequent exposure to the same type of antigens will stimulate a secondary response, in which a higher concentration of antibodies specific for the antigens are reproduced rapidly and efficiently in a short time for the elimination of the pathogen. Under specific circumstances, low doses of vaccines are given initially, followed by additional doses named booster doses. Boosters can effectively maintain the level of memory cells in the human body, hence extending a person's immunity.
Sources: en.wikipedia.org
=== Protein Purification === A significant application of synthetic biomolecular condensates is in the field of protein purification, offering an alternative to traditional methods like chromatography. The PandaPure technology leverages the principles of LLPS to isolate specific proteins of interest directly within host cells like E. coli. In one example, the researcher harnesses RNA-based TEARS system and co-express the target protein, which is autonomously captured and sorted into these synthetic organelles within the cell. After harvesting the cells, they are lysed to release the organelles, which now contain the concentrated target protein. Finally, in situ tag cleavage is mediated to release pure, tag-free protein from the organelle. This method simplifies the purification process into a single operation that includes tag removal, eliminating the need for columns, resins, or magnetic beads. It significantly reduces manual labor, time, and waste compared to conventional purification techniques.
A tetrahedral intermediate is a reaction intermediate in which the bond arrangement around an initially double-bonded carbon atom has been transformed from trigonal to tetrahedral. Tetrahedral intermediates result from nucleophilic addition to a carbonyl group. The stability of tetrahedral intermediate depends on the ability of the groups attached to the new tetrahedral carbon atom to leave with the negative charge. Tetrahedral intermediates are very significant in organic syntheses and biological systems as a key intermediate in esterification, transesterification, ester hydrolysis, formation and hydrolysis of amides and peptides, hydride reductions, and other chemical reactions.
O'Neill opposed some of the tax cuts on the basis they would contribute to budget deficits and undermine Social Security. O'Neill disputes the claim, made in Bush's book Decision Points, that he never openly disagreed with him on planned tax cuts. By 2003, the economy showed signs of improvement, though job growth remained stagnant. Another tax cut was passed that year. Between 2001 and 2008, GDP grew at an average annual rate of 2.125%, less than for past business cycles. Bush entered office with the Dow Jones Industrial Average at 10,587, and the average peaked in October 2007 at over 14,000. When Bush left office, the average was at 7,949, one of the lowest levels of his presidency. Only four other U.S. presidents have left office with the stock market lower than when they began. Unemployment originally rose from 4.2% in January 2001 to 6.3% in June 2003, but subsequently dropped to 4.5% in July 2007. Adjusted for inflation, median household income dropped by $1,175 between 2000 and 2007, while Professor Ken Homa of Georgetown University noted that "Median real after-tax household income went up two percent". The poverty rate increased from 11.3% in 2000 to 12.3% in 2006 after peaking at 12.7% in 2004. By October 2008, due to increases in spending, the U.S. national debt had risen to $11.3 trillion, more than doubling it since 2000. Most debt was accumulated as a result of what became known as the "Bush tax cuts" and increased national security spending.
Using X-ray diffraction, as well as other data from Rosalind Franklin and her information that the bases were paired, James Watson and Francis Crick arrived at the first accurate model of DNA's molecular structure in 1953, which was accepted through inspection by Rosalind Franklin.They used Erwin Chargaff's rules that in a species, the percent of adenine equaled the percent of thymine and the percent of guanine equaled the percent of cytosine. They wrote: "It has not escaped our notice that the specific pairing we have postulated immediately suggests a possible copying mechanism for the genetic material." The discovery was announced on February 28, 1953; the first Watson/Crick paper appeared in Nature on April 25, 1953. Sir Lawrence Bragg, the director of the Cavendish Laboratory, where Watson and Crick worked, gave a talk at Guy's Hospital Medical School in London on Thursday, May 14, 1953, which resulted in an article by Ritchie Calder in the News Chronicle of London, on Friday, May 15, 1953, entitled "Why You Are You. Nearer Secret of Life." The news reached readers of The New York Times the next day; Victor K. McElheny, in researching his biography, "Watson and DNA: Making a Scientific Revolution", found a clipping of a six-paragraph New York Times article written from London and dated May 16, 1953, with the headline "Form of 'Life Unit' in Cell Is Scanned." The article ran in an early edition and was then pulled to make space for news deemed more important. (The New York Times subsequently ran a longer article on June 12, 1953).
== Pathogenesis == The body uses glucose for energy. Without insulin, glucose is unable to enter the cells where it will be used for this and other anabolic ("building up") purposes, such as the synthesis of glycogen, proteins, and fatty acids. Insulin is also an active preventor of the breakdown or catabolism of glycogen and fat. The absence of sufficient insulin causes this breaking-down process to be accelerated; it is the mechanism behind metabolizing fat instead of glucose and the appearance of ketones. Since the glucose that normally enters the cells is unable to do so without insulin, it begins to build up in the blood where it can be seen as hyperglycemia or high blood glucose levels. The tubules of the kidneys are normally able to re-absorb glucose, but they are unable to handle and process the amount of glucose they are being presented with. At this point, which is called the renal threshold, the excess glucose spills into the urine (glycosuria), where it can be seen in urine glucose testing. It is the polyuria, or over-frequent urination, which causes polydipsia, or excessive water consumption, through an osmotic process. Even though there is an overabundance of glucose, the lack of insulin does not allow it to enter the cells. As a result, they are not able to receive nourishment from their normal glucose source. The body begins using fat for this purpose, causing weight loss; the process is similar to that of starvation.
Sources: en.wikipedia.org
To address the destruction, a commission created by the law of February 12, 1872, was tasked with reconstructing Parisian civil records before 1860. This work relied on cross-referencing family papers (notices in particular), notarial deeds, and records of parish and civil acts compiled before 1871 by archivists such as Auguste Jal, especially for prominent individuals. However, the main sources used were Catholic registers from 1793 to 1860, preserved in parishes and had not been burned. Accompanied by alphabetical index cards for searching, the reconstructed records were produced in duplicate through three distinct methods:
In biology and biochemistry, the active site is the region of an enzyme where substrate molecules bind and undergo a chemical reaction. The active site consists of amino acid residues that form temporary bonds with the substrate, the binding site, and residues that catalyse a reaction of that substrate, the catalytic site. Although the active site occupies only ~10–20% of the volume of an enzyme, it is the most important part as it directly catalyzes the chemical reaction. It usually consists of three to four amino acids, while other amino acids within the protein are required to maintain the tertiary structure of the enzymes. Each active site is evolved to be optimised to bind a particular substrate and catalyse a particular reaction, resulting in high specificity. This specificity is determined by the arrangement of amino acids within the active site and the structure of the substrates. Sometimes enzymes also need to bind with some cofactors to fulfil their function. The active site is usually a groove or pocket of the enzyme which can be located in a deep tunnel within the enzyme, or between the interfaces of multimeric enzymes. An active site can catalyse a reaction repeatedly as residues are not altered at the end of the reaction (they may change during the reaction, but are regenerated by the end). This process is achieved by lowering the activation energy of the reaction, so more substrates have enough energy to undergo reaction.
Surprisingly, little or no sexual dysfunction, including loss of sex drive and decreased sexual activity, has been observed in clinical studies of NSAA monotherapy. The explanation for this is that NSAAs do not lower androgen levels, and metabolites of testosterone like estrogens and neurosteroids may be of critical importance for maintenance of sex drive and function in males. In accordance, testosterone is locally aromatized into estradiol widely throughout the brain and estradiol appears to be the mediator of many of the central actions of testosterone. For these reasons, unlike antigonadotropic antiandrogens, NSAA monotherapy may have limited usefulness in the management of paraphilias and hypersexuality. The addition of NSAAs to antigonadotropic antiandrogens like GnRH analogues may have some usefulness however, particularly in severe cases. In any case, insufficient evidence is available at this time, and further research is thus warranted.
The structures are supported by collagen fibres set at right angles to each other and arranged in a three-dimensional web with the ossicles and papulae in the interstices. This arrangement enables both easy flexion of the arms and the rapid onset of stiffness and rigidity required for some actions performed under stress.
Spermidine has also been found to "upregulate expression of the epithelial stem cell-associated keratins K15 and K19, and dose-dependently modulated K15 promoter activity in situ and the colony forming efficiency, proliferation and K15 expression of isolated human K15-GFP+ cells in vitro."
Sources: en.wikipedia.org
It is a synthetic REV-ERB agonist used mainly in preclinical research. It is not an approved medicine for human use.
It binds to REV-ERBα and REV-ERBβ, nuclear receptors involved in circadian and metabolic gene regulation. This can alter transcription of genes related to lipid and glucose metabolism in experimental models.
No controlled human trials have established that effect. Endurance findings come primarily from rodent studies, and human responses remain unknown.
SR9009 is a synthetic research compound that binds and modulates the nuclear receptors REV-ERBα and REV-ERBβ. It is used in laboratory studies of circadian biology and metabolism, not as an approved medicine. It is also known by the informal name Stenabolic.