LC-MS raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
Reviewed 2026-02-11. Anything still debated is marked as such rather than presented as settled.
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 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.
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.
Physicochemical behavior influences handling. SR9009 is described as a solid with limited aqueous solubility, so organic solvents such as dimethyl sulfoxide or ethanol are common in research stock solutions. Aqueous dilution can produce precipitates if the organic content is too low. Light, heat, and repeated freeze-thaw cycles may affect stability. Storage recommendations usually specify a desiccated freezer environment protected from light, but exact stability data depend on the formulation and matrix.
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.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic REV-ERB agonist | Small molecule; not a steroid or peptide. |
| Primary targets | NR1D1 and NR1D2 | Also known as REV-ERBα and REV-ERBβ. |
| Studied routes | Intraperitoneal in rodents | Oral bioavailability in humans is not established. |
| Human approval | No approved therapeutic indication | No recognized clinical use. |
| Key uncertainty | Human physiological effects | Preclinical findings may not translate. |
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, lipid metabolism, and inflammatory gene expression. In cell and animal experiments, SR9009 alters transcription of clock-controlled genes and metabolic pathways. The compound is not a hormone and does not resemble classical steroid structures. Its activity depends on binding to the ligand-binding domain of REV-ERB, where it can modify corepressor recruitment.
Research interest in SR9009 grew from studies of circadian biology and metabolic disease. Preclinical reports describe effects on exercise capacity, muscle metabolism, and blood lipid levels in rodents, but these findings come from controlled laboratory settings. The compound has low oral bioavailability in animals, which limits systemic exposure after swallowing. Investigators often use injected routes in experiments to achieve measurable plasma concentrations. Human clinical data are sparse, no approved therapeutic product exists, and whether animal effects translate to humans remains an open question.
Regulatory and sporting contexts treat SR9009 as a prohibited substance in many elite competitions. Its presence on banned lists reflects concerns about performance enhancement and unknown long-term safety. Analytical chemists have developed methods to detect the parent compound and its metabolites in urine and blood. Literature discussions distinguish between in vitro potency, animal pharmacology, and anecdotal human reports. The latter are difficult to verify because products sold online may lack purity or contain different compounds.
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.
Identity and purity testing for SR9009 commonly uses liquid chromatography coupled with tandem mass spectrometry. This method separates the compound from matrix components and detects it by mass-to-charge transitions, providing sensitive and specific confirmation. Nuclear magnetic resonance spectroscopy can support structural identification, while high-performance liquid chromatography with ultraviolet detection may estimate purity. Because online products labeled as SR9009 may contain other substances or no active compound at all, independent verification is important in research settings. Certificates of analysis are useful but not a substitute for in-house testing.
Laboratory samples of SR9009 are typically supplied as a white to off-white powder. The compound dissolves readily in organic solvents such as dimethyl sulfoxide and ethanol, while its solubility in water is low. Because of this solubility profile, researchers often prepare concentrated stock solutions in an organic solvent before diluting them into aqueous assay buffers. Light exposure, moisture, and repeated freeze-thaw cycles can degrade many small molecules, so handling procedures usually aim to minimize these factors. Purity is commonly checked before use.
Storage conditions for research-grade SR9009 generally involve a freezer at approximately minus twenty degrees Celsius, sometimes lower for long-term preservation. Containers should remain tightly closed and protected from light. Desiccants may be used to limit moisture uptake. Solutions are often stored in aliquots to avoid repeated warming and cooling. Stability data for the compound under various conditions are limited, so laboratories typically follow supplier recommendations and verify performance through periodic analytical checks rather than assuming indefinite stability.
=== Fungal inhibitors === A chromogranin A-derived antifungal peptide (CGA 47–66, chromofungin) when embedded on a surface has been shown to have antifungal activity by interacting with the fungal membrane and thereby penetrating the cell. Additionally, in vitro studies have demonstrated that such an antifungal coating can inhibit the growth of yeast Candida albicans by 65% and completely stop the proliferation of filamentous fungus Neurospora crassa. Copper and copper alloy surfaces have demonstrated a die-off of Aspergillus spp., Fusarium spp., Penicillium chrysogenum, Aspergillus niger and Candida albicans fungal spores. Hence, the potential to help prevent the spread of fungi that cause human infections by using copper alloys (instead of non-antifungal metals) in air conditioning systems is worthy of further investigation.
The Houthis began protesting against Hadi's government to demand concessions in order to resolve a years-long insurgency they had been waging against the Yemeni state in mid-2014. The uprising escalated dramatically as Houthi fighters swept into Sanaa, the capital, and effectively seized control of the city from the Yemeni military within a couple of days in September. The forces of General Ali Mohsen al-Ahmer surrendered to the Houthis after a brief fight. Ali Abdullah Saleh, the former president, was widely suspected of aiding the Houthis behind the scenes and helping pave the way for their takeover. Prime Minister Mohammed Basindawa resigned on 21 September as part of a deal meant to end the standoff.
The plasma ionized calcium (Ca2+) concentration is very tightly controlled by a pair of homeostatic mechanisms. The sensor for the first one is situated in the parathyroid glands, where the chief cells sense the Ca2+ level by means of specialized calcium receptors in their membranes. The sensors for the second are the parafollicular cells in the thyroid gland. The parathyroid chief cells secrete parathyroid hormone (PTH) in response to a fall in the plasma ionized calcium level; the parafollicular cells of the thyroid gland secrete calcitonin in response to a rise in the plasma ionized calcium level. The effector organs of the first homeostatic mechanism are the bones, the kidney, and, via a hormone released into the blood by the kidney in response to high PTH levels in the blood, the duodenum and jejunum. Parathyroid hormone (in high concentrations in the blood) causes bone resorption, releasing calcium into the plasma. This is a very rapid action which can correct a threatening hypocalcemia within minutes. High PTH concentrations cause the excretion of phosphate ions via the urine. Since phosphates combine with calcium ions to form insoluble salts (see also bone mineral), a decrease in the level of phosphates in the blood, releases free calcium ions into the plasma ionized calcium pool. PTH has a second action on the kidneys. It stimulates the manufacture and release, by the kidneys, of calcitriol into the blood.
Sources: en.wikipedia.org
=== Substrates === Substrates within the muscle serve to power muscular contractions. They include molecules such as adenosine triphosphate (ATP), glycogen and creatine phosphate. ATP binds to the myosin head and causes the 'ratchetting' that results in contraction according to the sliding filament model. Creatine phosphate stores energy so ATP can be rapidly regenerated within the muscle cells from adenosine diphosphate (ADP) and inorganic phosphate ions, allowing for sustained powerful contractions that last between 5–7 seconds. Glycogen is the intramuscular storage form of glucose, used to generate energy quickly as intramuscular phosphocreatine stores become exhausted, producing lactic acid as a metabolic byproduct. Substrate shortage is one of the causes of metabolic fatigue. Substrates are depleted during exercise or are unable to be metabolized (e.g. metabolic myopathies), resulting in a lack of intracellular energy sources to fuel contractions. In essence, the muscle stops contracting because it lacks the energy to do so.
Activated factor X (FXa) is the sole enzyme that catalyzes the conversion of prothrombine into thrombin, which is vital in the coagulation cascade. Draculin is a member of the Lactoferrin family of proteins that functions as an antibacterial protein in other mammals, but has been co-opted in bat evolution to function as an anticoagulant.
transuranic elements Also transuranium elements. The set of chemical elements with an atomic number greater than 92, i.e. occurring after uranium in the periodic table. None of the transuranic elements are stable in naturally occurring conditions.
Sources: en.wikipedia.org
The situation has also reignited a debate over gain-of-function research, although the intense political rhetoric surrounding the issue has threatened to sideline serious inquiry over policy in this domain.
=== Theories of origin === The most commonly held of the three theories of tofu's origin maintains that tofu was discovered by Liu An (179–122 BC), a Han dynasty prince. While plausible, the paucity of reliable sources for this period makes this difficult to conclusively determine. In Chinese history, important inventions were frequently attributed to important leaders and figures of the time. It was used as a cheaper option to meat. In 1960, a stone mural unearthed from an Eastern Han dynasty tomb provided support for the theory of the Han origin of tofu; however some scholars maintain that tofu during the Han dynasty was rudimentary and lacked the firmness and taste for it to be considered as tofu. Another theory suggests that the production method for tofu was discovered accidentally when a slurry of boiled, ground soybeans was mixed with impure sea salt. Such sea salt would probably have contained calcium and magnesium salts, allowing the soy mixture to curdle and produce a tofu-like gel. The last group of theories maintains that the ancient Chinese learned the method for curdling soy milk by emulating the milk curdling techniques of the Mongolians. The primary evidence for this theory is the etymological similarity between the Chinese term rǔfǔ (乳腐), which literally means "milk curd", used during Sui dynasty (AD 581–618), for dishes with a consistency like yogurt or soft cheese, later influenced by Mongolian milk products and methods of production, and the term dòufu (豆腐, "bean curd") or tofu.
=== Ancient === 350 BCE — The Greek philosopher Aristotle, arguably the first philosopher to make a serious attempt to scientifically explain aging, proposes his thesis on aging. He suggests that aging is a process by which human and animal bodies, which are naturally hot and wet, gradually become dry and cold, and theorizes that more moisture delays aging. 259–210 BCE — years of life of the Chinese emperor Qin Shi Huang, who united China under his rule. All his life he persistently searched for an elixir of youth and died trying, presumably taking "pills of immortality", containing mercury. 156–87 BCE — years of life of the Chinese emperor Wu of Han, who persistently tried to find a way to achieve immortality, mainly by means of magic. He used services of various magicians. But Wu of Han was not a naive person – he thoroughly rechecked their abilities and if he identified the person as a quack, he executed him. 63 BC–14 CE — years of life of Caesar Augustus, the first Roman emperor, who is considered one of the most effective leaders of the Ancient Rome. For him an eternal youth was an obsession. In particular, contrary to the Roman tradition to create statues as realistic as possible, he always ordered to portray himself young. There are many of his "youthful" statues but researchers still do not know how he looked in old age. 3rd–17th century — the period of alchemy. There are several directions in alchemy, and it was distributed over a huge territory.
=== Robin Williamson === Robin Williamson (Jonjo O'Neill) is the chief communications officer at Tender, assisting Whitney in pivoting the company into banking. During the launch of Tender's banking app, Robin clashes with Yasmin over their dueling PR strategies, with Robin preferring a more traditional rollout via tech publications and podcasts, while Yasmin seeks to capitalize on Henry Muck's profile as CEO by booking him a keynote speech. Yasmin's approach wins over Whitney, who promotes Yasmin to head of communications and fires Robin, deeming him too traditional and risk-averse.
Sources: en.wikipedia.org
It is a synthetic compound that acts as an agonist at REV-ERBα and REV-ERBβ. It is used mainly as a research chemical to study circadian and metabolic pathways. It is not approved for human therapeutic use.
REV-ERB receptors generally repress transcription when bound by natural heme. SR9009 is described as an agonist that enhances this repressive activity. The result is altered expression of clock and metabolic genes.
Published controlled human trials are lacking. Some sources cite limited or unofficial reports, but these do not establish safety or efficacy. Claims about human performance effects remain unverified.
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.