A practical reference on LC-MS/MS: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
This page was last updated on 2026-05-18 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.
Detection in biological samples can be complicated by rapid metabolism and low circulating concentrations. Some studies report phase I and phase II metabolites, and analytical methods may need to target those species in addition to the parent compound. Immunoassays are not broadly available, so mass spectrometry remains the main confirmatory approach. For anti-doping testing, laboratories look for SR9009 and its metabolites using validated LC-MS methods. Open questions include how long metabolites remain detectable and how different routes of administration alter detection windows.
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.
| 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 |
Pharmacokinetic data for SR9009 are limited in published literature. Some reports indicate low oral bioavailability and rapid clearance in animals, which complicates interpretation of exposure and effect. Researchers often use injected routes in preclinical work to achieve measurable systemic levels. Analytical studies rely on mass spectrometry to detect the parent compound and its metabolites. Questions about tissue distribution, active metabolites, and long-term consequences remain open. Species differences in metabolism can affect observed half-life and target engagement.
SR9009 is a synthetic small molecule studied as an agonist of the nuclear receptors REV-ERBα and REV-ERBβ. These receptors help regulate circadian rhythms and metabolic gene expression. In laboratory experiments, SR9009 binds these receptors and alters transcription of genes involved in lipid handling, glucose metabolism, and mitochondrial function. It is not a naturally occurring compound and has no approved therapeutic use. Research interest stems from its ability to modify energy metabolism in cells and animal models.
In rodent studies, SR9009 has been reported to increase mitochondrial content in skeletal muscle and improve exercise endurance under some conditions. These findings led to popular descriptions such as an exercise mimetic, although that term oversimplifies the biology. Effects vary by dose, timing, tissue, and model. The compound's influence on circadian pathways means that time of administration can matter in experiments. Whether similar metabolic changes occur in humans remains largely unexplored in controlled published trials.
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.
Muscular dystrophies may be X-linked recessive, autosomal recessive, or autosomal dominant. Diagnosis often involves blood tests and genetic testing. There is no cure for any disorder from the muscular dystrophy group. Several drugs designed to address the root cause are currently available including gene therapy (Elevidys), and antisense drugs (Ataluren, Eteplirsen etc.). Other medications used include glucocorticoids (Deflazacort, Vamorolone); calcium channel blockers (Diltiazem); to slow skeletal and cardiac muscle degeneration, anticonvulsants to control seizures and some muscle activity, and Histone deacetylase inhibitors (Givinostat) to delay damage to dying muscle cells. Physical therapy, braces, and corrective surgery may help with some symptoms while assisted ventilation may be required in those with weakness of breathing muscles. Outcomes depend on the specific type of disorder. Many affected people will eventually become unable to walk and Duchenne muscular dystrophy in particular is associated with shortened life expectancy. Muscular dystrophy was first described in the 1830s by Charles Bell. The word "dystrophy" comes from the Greek dys, meaning "no, un-" and troph- meaning "nourish".
This resulted in the creation of the NOD-scid mice which lacked T cells, B cells, and NK cells. This mouse model permitted for a slightly higher level of human cell reconstitution. Nevertheless, a major breakthrough in this field came with the introduction of the mutant IL-2 receptor (IL2rg) gene in the NOD-scid model. This accounted for the creation of the NOD-scid-γcnull mice (NCG, NSG or NOG) models which were found to have defective signaling of interleukins IL-2, IL-4, IL-7, IL-9, IL-15 and IL-21. Researchers evolved this NSG model by knocking out the RAG1 and RAG2 genes (recombination activation genes), resulting into the RAGnull version of the NSG model that was devoid of major cells of the immune system including the natural killer cells, B lymphocytes and T lymphocytes, macrophages and dendritic cells, causing the greatest immunodeficiency in mice models so far. The limitation with this model was that it lacked the human leukocyte antigen. In accordance to this limitation, the human T cells when engrafted in the mice, failed to recognize human antigen-presenting cells, which consequated in defective immunoglobulin class switching and improper organization of the secondary lymphoid tissue. To circumvent this limitation, the next development came with the introduction of transgenes encoding for HLA I and HLA II in the NSG RAGnull model that enabled buildout of human T-lymphocyte repertoires as well as the respective immune responses. Mice with such human genes are technically human-animal hybrids.
There are colloidal methods to produce many different semiconductors. Typical dots are made of binary compounds such as lead sulfide, lead selenide, cadmium selenide, cadmium sulfide, cadmium telluride, indium arsenide, and indium phosphide. Dots may also be made from ternary compounds such as cadmium selenide sulfide. Further, recent advances have been made which allow for synthesis of colloidal perovskite quantum dots. These quantum dots can contain as few as 100 to 100,000 atoms within the quantum dot volume, with a diameter of approximately 10 to 50 atom diameters. This corresponds to about 2 to 10 nanometers, and at 10 nm in diameter, nearly 3 million quantum dots could be lined up end to end and fit within the width of a human thumb.
=== Homology === GsMTx-4 shares less than 50% of its sequence homology with all other known peptide toxins. The highest percentage of sequence homology is shared with other tarantula toxins that block voltage-gated calcium channels and voltage-gated potassium channels. The ICK, as well as the residues F4, D13, and L20, are conserved in these tarantula toxins.
=== Neuroendocrine === The nervous system coordinates the actions and sensory information of a person by transmitting signals to and from different parts of the body, working in tandem with the endocrine system to respond to environmental events. The endocrine system comprises feedback loops of hormones that are released by glands directly into the circulatory system, which target and regulate distant organs. In vertebrates, the hypothalamus is the neural control center for all endocrine systems, being adjacent to the pituatary gland, and linking the two systems together as the neuroendocrine system.
Sources: en.wikipedia.org
== Other animals == Rhabdomyolysis is recognized in horses. Horses can develop several muscle disorders, many of which may progress to rhabdomyolysis. Of these, some cause isolated attacks of rhabdomyolysis (e.g., dietary deficiency in vitamin E and selenium, poisoning associated with pasture or agricultural poisons such as organophosphates), while others predispose to exertional rhabdomyolysis (e.g., the hereditary condition equine polysaccharide storage myopathy). Of thoroughbred horses, 5–10% and some standardbred horses have the condition equine exertional rhabdomyolysis; no specific cause has been identified, but an underlying muscle calcium regulation disorder is suspected. Rhabdomyolysis affecting horses may also occur in outbreaks; these have been reported in many European countries, and later in Canada, Australia, and the United States. It has been referred to as "atypical myopathy" or "myoglobinuria of unknown etiology". No single cause has yet been found, but various mechanisms have been proposed, and a seasonal pattern has been observed. Very high creatine kinase levels are detected, and mortality from this condition is 89%.
C3S: alite (3CaO·SiO2); C2S: belite (2CaO·SiO2); C3A: tricalcium aluminate (3CaO·Al2O3) (historically, and still occasionally, called celite); C4AF: Calcium aluminoferrite (4CaO·Al2O3·Fe2O3). The silicates are responsible for the cement's mechanical properties — the tricalcium aluminate and brownmillerite are essential for the formation of the liquid phase during the sintering (firing) process of clinker at high temperature in the kiln. The chemistry of these reactions is not completely clear and is still the object of research. First, the limestone (calcium carbonate) is burned to remove its carbon, producing lime (calcium oxide) in what is known as a calcination reaction. This single chemical reaction is a major emitter of global carbon dioxide emissions.
Pain: Sacral, coccygeal (tailbone), gluteal, groin, rectum, and perineal regions Sciatica and leg pain Foot and toe pain Persistent genital arousal disorder (PGAD) or pudendal neuralgia Neuropathic pain characterized by burning (dysesthesia), aching, or stabbing sensations Sensory Disturbances: Paresthesias such as tingling, electric shocks, buzzing or internal vibrations Fasciculations (muscle twitching) Numbness or other sensory deficits Motor Dysfunction: Muscle weakness (Paresis) in the legs and feet Toe cramping and muscle spasms Foot Drop (Rarely) Bladder, Bowel, Sexual Dysfunction: Neurogenic bladder: urinary retention, hesitation, Valsalva voiding, increased frequency and urgency, painful bladder, urge incontinence, and stress incontinence. Neurogenic bowel: constipation, diarrhea, cramping, urgency, changes in defecation frequency, false urge to defecate, fecal incontinence, anal sphincter pain or pressure. Erectile dysfunction; retrograde ejaculation Positional Aggravation: Symptoms are typically worsened by standing, walking, sitting, or bending Lying down (recumbency) may provide partial or temporary symptom relief
==== Triptans (serotonin 5-HT1B and 5-HT1D receptor agonists) ==== Almotriptan (Almogran; Axert; LAS-31416) – serotonin 5-HT1B and 5-HT1D receptor agonist and triptan – migraine [119] Eletriptan (Relert; Relpax; UK-116044) – serotonin 5-HT1B and 5-HT1D receptor agonist and triptan – migraine, menstrual migraine [120] Frovatriptan (Allegro; Auradol; EN-3266; Frova; Isimig; Migard; Pitunal; Rilamig; SB-209509; SB-209509AX; VML-251) – serotonin 5-HT1B and 5-HT1D receptor agonist and triptan – migraine [121] Naratriptan (Amerge; GR-85548; GR-85548A; Naramig; SMP-948) – serotonin 5-HT1B and 5-HT1D receptor agonist and triptan – migraine [122] Rizatriptan (L-705126; Maxalt; MK-0462; MK-462) – serotonin 5-HT1B and 5-HT1D receptor agonist and triptan – migraine [123] Rizatriptan oral film (INT-0008; RHB-103; Rizafilm; VersaFilm; RizaPort) – serotonin 5-HT1B and 5-HT1D receptor agonist and triptan – migraine [124] Sumatriptan (Imigran Nasal Spray; Imitrex Nasal Spray) – serotonin 5-HT1B and 5-HT1D receptor agonist and triptan – migraine [125] Zolmitriptan (311-C90; 311C; AscoTop; BW-311C90; Zomig; Zomigon) – serotonin 5-HT1B and 5-HT1D receptor agonist and triptan – cluster headache, menstrual migraine, migraine [126] Zolmitriptan oral dispersible film (zolmitriptan ODF; Zolmitriptan PharmaFilm; Zolmitriptan RapidFilm; Zolmitriptan Renantos Schmelzfilm) – serotonin 5-HT1B and 5-HT1D receptor agonist and triptan – migraine [127]
== Plays == Vera; or, The Nihilists (1880/1882) (text) The Duchess of Padua (1883) (text) Lady Windermere's Fan (1892) (text) A Woman of No Importance (1893) (text) An Ideal Husband (1895) (text) The Importance of Being Earnest (1895) (text) Salomé (1896) Translated from French by Lord Alfred Douglas (text) La Sainte Courtisane (Incomplete) (text) A Florentine Tragedy (Incomplete) (text) (Dates are dates of first performance, which approximate better to the probable date of composition than dates of publication.)
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.
It is usually detected by LC-MS or HPLC-UV against a reference standard. In biological matrices, metabolite targeting can improve detection. No universal immunoassay is widely available.