LC-MS/MS raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
This page was last updated on 2026-07-15 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.
In laboratory settings, SR9009 is commonly identified by its molecular structure and its interaction with REV-ERB receptors. Vendors may list it under synonyms such as Stenabolic or REV-ERB agonist, but those names do not define purity or identity. Analytical confirmation typically uses high-performance liquid chromatography with ultraviolet detection or liquid chromatography–mass spectrometry. A reference standard is needed to compare retention time and mass spectrum, because the compound can be confused with related research chemicals.
Handling practices for SR9009 focus on minimizing degradation and contamination. The solid is generally stored desiccated at or below -20 °C, protected from light and moisture. Stock solutions are often prepared in dimethyl sulfoxide or ethanol, then aliquoted to avoid repeated freeze–thaw cycles. Aqueous solubility is low, so formulations for animal studies may require cosolvents or suspending agents. Personnel should follow institutional chemical safety procedures, because toxicological data for humans are incomplete.
| 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. |
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.
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.
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.
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.
==== Antigen-dependent theories ==== These theories consider a specific combination of antigen peptide sequence and the binding groove (B pocket) of HLA-B27 (which will have different properties from the other HLA-B alleles). The arthritogenic peptide hypothesis suggests that HLA-B27 has a unique ability to bind antigens from a microorganism that triggers a CD8 T-cell response that cross-reacts with a HLA-B27/self-peptide pair. HLA-B27 can bind peptides at the cell surface. The molecular mimicry hypothesis is similar, although it suggests that cross-reactivity between some bacterial antigens and self-peptides can break tolerance and lead to autoimmunity.
Medical schools began to be set up in the United States towards the end of the 18th century. Classes in anatomy needed a continual stream of cadavers for dissection, and these were difficult to obtain. Philadelphia, Baltimore, and New York were all renowned for body snatching activity as criminals raided graveyards at night, removing newly buried corpses from their coffins. A similar problem existed in Britain where demand for bodies became so great that grave-raiding and even anatomy murder were practised to obtain cadavers. Some graveyards were, in consequence, protected with watchtowers. The practice was halted in Britain by the Anatomy Act of 1832, while in the United States, similar legislation was enacted after the physician William S. Forbes of Jefferson Medical College was found guilty in 1882 of "complicity with resurrectionists in the despoliation of graves in Lebanon Cemetery".The teaching of anatomy in Britain was transformed by Sir John Struthers, Regius Professor of Anatomy at the University of Aberdeen from 1863 to 1889. He was responsible for setting up the system of three years of "pre-clinical" academic teaching in the sciences underlying medicine, including especially anatomy. This system lasted until the reform of medical training in 1993 and 2003. As well as teaching, he collected many vertebrate skeletons for his museum of comparative anatomy, published over 70 research papers, and became famous for his public dissection of the Tay Whale. From 1822 the Royal College of Surgeons regulated the teaching of anatomy in medical schools.
The exact serotonin receptors responsible for MDMA's entactogenic effects are unclear, but may include the serotonin 5-HT1A receptor, 5-HT1B receptor, and 5-HT2A receptor, as well as 5-HT1A receptor-mediated oxytocin release and consequent activation of the oxytocin receptor. The role of oxytocin in the effects of MDMA was demonstrated in people with arginine vasopressin deficiency (central diabetes insipidus), who have oxytocin deficiency and in whom MDMA fails to elevate oxytocin levels and shows greatly blunted entactogenic effects. Induction of dopamine release is thought to be importantly involved in the stimulant and euphoriant effects of MDMA, while induction of norepinephrine release and serotonin 5-HT2A receptor stimulation are believed to mediate its sympathomimetic effects. Activation of serotonin 5-HT1B and 5-HT2A receptors is also thought to be involved in the stimulant and euphoriant effects of MDMA, while serotonin 5-HT2C receptor activation is thought to constrain these effects and limit MDMA's reinforcing potential. Serotonin 5-HT2B receptor signaling appears to be required for MDMA-induced serotonin release and effects. MDMA has been associated with a unique subjective "magic" or euphoria that few or no other known entactogens are said to fully reproduce. The mechanisms underlying this property of MDMA are unknown, but it has been theorized to be due to a specific mixture and balance of pharmacological activities, including combined serotonin, norepinephrine, and dopamine release and direct serotonin receptor agonism.
Sources: en.wikipedia.org
=== Phosphorylation === Stimuli such as hormones, growth factors, and mitogens that promote cell proliferation also enhance translation rates by phosphorylating eIF4E. Although eIF4E phosphorylation and translation rates are not always correlated, consistent patterns of eIF4E phosphorylation are observed throughout the cell cycle; wherein low phosphorylation is seen during G0 and M phase and wherein high phosphorylation is seen during G1 and S phase. This evidence is further supported by the crystal structure of eIF4E which suggests that phosphorylation on serine residue 209 may increase the affinity of eIF4E for capped mRNA. eIF4E phosphorylation is also related to its ability to suppress RNA export and its oncogenic potential as first shown in cell lines.
The Sam and Ann Barshop Institute for Longevity and Aging Studies is a basic and clinical research institute located on the Greehey Academic and Research Campus of the University of Texas Health Science Center at San Antonio (UTHSCSA). It is a leading institute in the United States in geriatrics research. The Barshop Institute ranks #1 in National Institute on Aging funding among Texas institutions and is highly ranked in the country in National Institute of Health funding. The scientific director of the institute has been Elena Volpi, M.D., PhD, FGSA since July 2023. In 2009, one of the research projects of the institute was announced by Science magazine as one of the top scientific discoveries of the year. The Barshop Institute is home to several prestigious National Institute on Aging (NIA) research centers and programs, including the Nathan Shock Center, the Claude D. Pepper Older Americans Independence Center, the Center for Alzheimer's Disease and Related Dementias Population Aging and Social Studies, and the Interventions Testing Program. Collectively, these NIH-supported initiatives advance the Institute's mission to uncover the biological mechanisms of aging, develop interventions that prevent or treat age-related diseases, and promote healthier aging across the lifespan.
For example, if the desired analyte has a high amount of acidity, it would be logical to choose a matrix with a high amount of basicity to avoid competition and facilitate the formation of an ion. The pH of the matrix can also be used to select what sample you want to obtain spectra for. For example, in the case of proteins, a very acidic pH can show very little of the peptide components, but can show very good signal for those components that are larger. If the pH is increased towards a more basic pH, then smaller components become easier to see.
Chemical specificity is the ability of binding site of a macromolecule (such as a protein) to bind specific ligands. The fewer ligands a protein can bind, the greater its specificity. Specificity describes the strength of binding between a given protein and ligand. This relationship can be described by a dissociation constant, which characterizes the balance between bound and unbound states for the protein-ligand system. In the context of a single enzyme and a pair of binding molecules, the two ligands can be compared as stronger or weaker ligands (for the enzyme) on the basis of their dissociation constants. (A lower value corresponds to a stronger binding.) Specificity for a set of ligands is unrelated to the ability of an enzyme to catalyze a given reaction, with the ligand as a substrate. If a given enzyme has a high chemical specificity, this means that the set of ligands to which it binds is limited, such that neither binding events nor catalysis can occur at an appreciable rate with additional molecules. An example of a protein-ligand pair whose binding activity can be highly specific is the antibody-antigen system. Affinity maturation typically leads to highly specific interactions, whereas naive antibodies are promiscuous and bind a larger number of ligands. Conversely, an example of a protein-ligand system that can bind substrates and catalyze multiple reactions effectively is the Cytochrome P450 system, which can be considered a promiscuous enzyme due to its broad specificity for multiple ligands.
Sources: en.wikipedia.org
== Taxonomy == The cabbage looper larva is a type of cabbage worm, a general term for a Lepidopteran pest that primarily feeds on crucifers. They closely resemble each other, in that they are all smooth and green, but they are not closely related in terms of phylogeny. In fact, none of the cabbage worms bear close phylogenetic relations, as they are all from different families. The cabbage looper is a member of the family Noctuidae, one of the largest families in Lepidoptera. It is related to other vegetable pests, like the cutworm and armyworms.
=== Insulin access and innovation === In response to rising insulin costs and research showing that many people with diabetes are skipping or rationing their insulin, Breakthrough T1D has advocated for insurance companies to provide better health coverage for those living with type 1 diabetes, including making out-of-pocket costs for insulin and other vital diabetes tools more predictable and reasonable. The aim of this advocacy is to ensure people have the freedom to choose treatment strategies that are appropriate for them, and to cover artificial pancreas/automated insulin delivery systems. In response to escalating insulin affordability issues, Breakthrough T1D partnered with nonprofit drug maker Civica to manufacture insulin that will cost $30 a vial, regardless of a patient's insurance provider. Civica insulin is expected to be available to the public in 2025. Breakthrough T1D also advocates for passage of the INSULIN Act, which caps cost-sharing under private health insurance for a month's supply of selected insulin products at $35 or 25% of a plan's negotiated price (after any price concessions), whichever is less, beginning in 2025.
=== Expansion === Due to the success of the Selous Scouts, Walls directed in mid-1974 that it be expanded from three to six troops. This process was completed by December 1974, and included 50 former insurgents being added to the unit. A Reconnaissance Troop was formed in the second half of 1976 to conduct scouting operations in Mozambique and Zambia; this unit had a peak strength of twelve men. As part of the expansion of the Selous Scouts, the Rhodesian Army's Tracking Wing and Tracker Combat Unit were merged into it during 1974. The Tracking Wing became the Selous Scouts' Training Troop. The Selous Scouts continued to deliver training in tracking and trackers for the remainder of the war, with this forming a cover for the unit's actual role. The Tracker Combat Unit was made up of white reservists; while these men were not suitable for Selous Scouts operations, they were retained to help provide cover. These changes reduced the effectiveness of the Rhodesian Army's tracking capabilities. The size of the Selous Scouts increased further over time, and eventually reached 1,800 men. Many of these were territorial soldiers who were not permanently attached. The rapid expansion of the Selous Scouts led to a drop in the quality of its personnel, which reduced the effectiveness of pseudo operations. This in turn caused the unit to increasingly undertake offensive operations where it directly attacked insurgents rather than gathered intelligence on them.
=== Phrixotoxin-3 === Injection of this venom into mice causes immediate general ataxia, lack to response stimuli and semi-paralysis. Inability to stand and breathing reduction occurs within minutes. Flaccid paralysis and slowing of breathing eventually cause death (Bosmans 2006).
In 2011, Sá Fernandes said that he had a solid accusation, but did not want to turn Dias into a "scapegoat," and in case there was any doubt, he would not ask for his conviction."We are sure that the defendant consummated the crime [of kidnapping] (...) doesn't have the slight sign of regret. Acts with total indifference (...) It was proven that the defendant kidnapped Rui Pedro, taking him to Lustosa against the minor's parent's will. (...) I evaluated the evidence and reached the conclusion that the defendant is the author of the facts judged here. I ask for justice and humanity for the case's resolution. In the end of this process there is sorrow and anguish for not finding out what happened to Pedro. The Public Prosecution asks for justice and waits for it to be done" - Public Prosecution, 2012When Dias' arrest was definitely announced, Manuel Mendonça said that the now convicted had multiple opportunities to tell what he did to Mendonça, even by anonymous letter and highlighted that he did not want his conviction. After being freed, Dias said in 2018 that he was a victim of "a great injustice" and blamed Mendonça's family for his jail time.
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.
Liquid chromatography–mass spectrometry is common for identity and purity checks. High-performance liquid chromatography with ultraviolet detection can also be used. Both methods require a suitable reference standard.