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Background And Receptor Pharmacology — Reference Sheet

By Editorial Desk · published 2026-01-05 · last reviewed 2026-02-12 · Blog

This is a working overview of research chemical, written for readers who want more than a one-paragraph summary but less than a textbook.

Reviewed 2026-02-12. Anything still debated is marked as such rather than presented as settled.

Background and Receptor Pharmacology

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 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.

Background and Pharmacological Mechanism

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 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 at a glance

PropertyValueNotes
Chemical classSynthetic REV-ERB agonistBinds REV-ERBα and REV-ERBβ in preclinical models
Molecular formulaC20H24ClN3O4SReported for the parent compound
CAS Registry Number1379686-30-2Common identifier in chemical databases
AppearanceOff-white to pale yellow solidTypical research chemical solid
SolubilitySoluble in DMSO and ethanol; low in waterClass: small organic molecule

Analytical and Handling Considerations

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.

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Detection, Regulation, and Misconceptions

Analytical chemists detect SR9009 with liquid chromatography-tandem mass spectrometry, commonly abbreviated LC-MS/MS. Sample preparation may involve protein precipitation, liquid-liquid extraction, or solid-phase extraction before analysis. Laboratories can target the parent compound or its metabolites, depending on the matrix and the purpose of testing. Anti-doping methods require sensitive and specific assays because concentrations in biological samples can be low. Reference standards and validated methods are essential for reliable identification and quantification.

Regulatory agencies have not approved SR9009 for human therapeutic use. It is typically sold as a research chemical with labels stating that it is not for human consumption. The World Anti-Doping Agency prohibits the substance in sport, generally under the category of non-approved substances. Customs and national laws may restrict importation, sale, or possession. Product quality and legal status can vary by country and vendor, and therapeutic claims are not permitted in regulated advertising because the compound lacks approval.

Several misconceptions surround SR9009. It is often described as a SARM, a steroid, or an exercise pill, but its known target is the REV-ERB receptor family. Rodent studies have examined exercise capacity and metabolic markers, yet human outcomes remain unproven. Oral bioavailability appears low in animals, and human pharmacokinetics are not well characterized. Online products may contain impurities or different compounds, so identity and purity testing are important for research use.

Handling Storage and Quality Control

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.

Background and Mechanism

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.

Notes from published material

Albumin-bound paclitaxel (brand name Abraxane, also called nab-paclitaxel) is an alternative formulation where paclitaxel is bound to albumin nanoparticles. Much of the clinical toxicity of paclitaxel is associated with the solvent Cremophor EL in which it is dissolved for delivery. Abraxis BioScience developed Abraxane, in which paclitaxel is bonded to albumin as an alternative delivery agent to the often toxic solvent delivery method. This was approved by the FDA in January 2005, for the treatment of breast cancer after failure of combination chemotherapy for metastatic disease or relapse within six months of adjuvant chemotherapy. It has since been approved for locally advanced or metastatic non-small cell lung cancer and metastatic adenocarcinoma of the pancreas as well. Taxanes, including paclitaxel, 10-deacetylbaccatin III, baccatin III, paclitaxel C, and 7-epipaclitaxel, have been found in the leaves and shells of hazel. The finding of these compounds in shells, which are considered discarded material and are mass-produced by many food industries, is of interest for the future availability of paclitaxel.

== Interactive pathway map == The diagram below shows human protein names. Names in other organisms may differ, and the numbers of isozymes (such as HK1, HK2, ...) likely differ also. Click on genes, proteins and metabolites below to link to respective articles.

=== Conceptual development === Ilyushin began work on the aerobus in late 1969, initially by assessing the development potential of existing aircraft. An enlarged Il-62 (the Il-62-250) would have had a 30-tonne payload, 259 seats and a 6.8 metre/22 ft longer fuselage: a virtual analogue of the Douglas DC-8 "Super Sixty" series. Other proposed Il-62 modifications involved double-deck and "two fuselages side-by-side" developments. There was also a project to "civilianise" the Il-76. From March 1970 the bureau developed all-new designs under the Il-86 designation. Instead of the "appropriate technology" approach of the Il-62, these designs were to have powered controls, complex high-lift devices and advanced automation which would reduce the number of flightdeck crew. An early avanproyekt was shown to the Soviet leadership at an exhibition of civil aviation innovations at Vnukovo-2 Airport near Moscow on May 17, 1971. A scale model with the designation of "Il-86" showed the "self-loading" concept with integral boarding stairs, below-deck luggage stores, and below-deck midships galley. It had a twin-aisle interior with nine-abreast seating in a "3–3–3" layout. Ilyushin considered it politic to make the interior wider than any planned airliner except the Boeing 747. The 6.07 m (19.9 ft) fuselage diameter was partly dictated by the need to provide standing room in the underfloor luggage compartments. The Il-86 had the second-widest fuselage of any airliner until the Boeing 777. On this basis, on 9 March 1972, the bureau was asked to proceed with detailed design.

Premnaspirodiene oxygenase (EC 1.14.14.151, HPO, Hyoscymus muticus premnaspirodiene oxygenase) is an enzyme with systematic name (-)-vetispiradiene,NADPH:oxygen 2alpha-oxidoreductase. It catalyses the following overall chemical reaction:

Sources: en.wikipedia.org

Further detail

The Southern Oscillation is the atmospheric component of ENSO. This component is an oscillation in surface air pressure between the tropical eastern and the western Pacific Ocean waters. The strength of the Southern Oscillation is measured by the Southern Oscillation Index (SOI). The SOI is computed from fluctuations in the surface air pressure difference between Tahiti (in the Pacific) and Darwin, Australia (on the Indian Ocean). El Niño episodes have negative SOI, meaning there is lower pressure over Tahiti and higher pressure in Darwin. La Niña episodes on the other hand have positive SOI, meaning there is higher pressure in Tahiti and lower in Darwin. Low atmospheric pressure tends to occur over warm water and high pressure occurs over cold water, in part because of deep convection over the warm water. El Niño episodes are defined as sustained warming of the central and eastern tropical Pacific Ocean, thus resulting in a decrease in the strength of the Pacific trade winds, and a reduction in rainfall over eastern and northern Australia. La Niña episodes are defined as sustained cooling of the central and eastern tropical Pacific Ocean, thus resulting in an increase in the strength of the Pacific trade winds, and the opposite effects in Australia when compared to El Niño. Although the Southern Oscillation Index has a long station record going back to the 1800s, its reliability is limited due to the latitudes of both Darwin and Tahiti being well south of the Equator, so that the surface air pressure at both locations is less directly related to ENSO.

Luminescence dating methods are not radiometric dating methods in that they do not rely on abundances of isotopes to calculate age. Instead, they are a consequence of background radiation on certain minerals. Over time, ionizing radiation is absorbed by mineral grains in sediments and archaeological materials such as quartz and potassium feldspar. The radiation causes charge to remain within the grains in structurally unstable "electron traps". Exposure to sunlight or heat releases these charges, effectively "bleaching" the sample and resetting the clock to zero. The trapped charge accumulates over time at a rate determined by the amount of background radiation at the location where the sample was buried. Stimulating these mineral grains using either light (optically stimulated luminescence or infrared stimulated luminescence dating) or heat (thermoluminescence dating) causes a luminescence signal to be emitted as the stored unstable electron energy is released, the intensity of which varies depending on the amount of radiation absorbed during burial and specific properties of the mineral. These methods can be used to date the age of a sediment layer, as layers deposited on top would prevent the grains from being "bleached" and reset by sunlight. Pottery shards can be dated to the last time they experienced significant heat, generally when they were fired in a kiln.

Teleost leptins are a family of peptide hormones found in fish (teleostei) that are orthologs of the mammalian hormone leptin. The teleost and mammalian leptins appear to have similar functions, namely, regulation of energy intake and expenditure. The leptin (LEP) hormone was long thought to be specific to mammals, but in recent years the gene (lep) has been found in amphibia such as the tiger salamander (Ambystoma tigrinum), and the African clawed frog (Xenopus laevi). The discovery of lep in puffer fish (Takifugu rubripes) demonstrates the ancient ancestry of this hormone.

Sources: en.wikipedia.org

Frequently asked questions

What is SR9009?

SR9009 is a synthetic small molecule studied as an agonist of the REV-ERB nuclear receptors. It is not an approved medicine, and its effects in humans are not well characterized.

Is SR9009 a hormone?

No. It is a synthetic ligand that binds nuclear receptors, not a steroid or peptide hormone. Its activity depends on receptor binding rather than endocrine secretion.

What is known about human use?

Clinical evidence is limited. Most published data come from cell and animal experiments. Human safety and efficacy remain uncertain.

What is SR9009?

It is a synthetic REV-ERB agonist used mainly in preclinical research. It is not an approved medicine for human use.

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