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Background And Receptor Pharmacology — Deep Dive

By Editorial Desk · published 2025-07-06 · last reviewed 2025-08-05 · Blog

Everything below concerns research chemical. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.

Last reviewed on 2025-08-05. Where a claim depends on a specific study, the study is described rather than over-claimed.

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 Mechanism

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.

Preclinical reports describe effects on exercise endurance, mitochondrial content, and lipid profiles in rodents, but these findings come from specific experimental conditions. Many studies use high doses or delivery methods that may not translate directly to human use. SR9009 has been reported to have low oral bioavailability and a short half-life, which complicates interpretation of oral dosing studies. It is not established as safe or effective for any indication. Literature discussions often separate its pharmacological mechanism from unverified claims made in fitness and supplement markets.

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

Background and Research Status

Most published work on SR9009 consists of preclinical studies. It is widely sold as a research chemical, a category that does not imply safety, efficacy, or pharmaceutical-grade quality. Sports anti-doping organizations have listed SR9009 as a prohibited substance, and its presence in an athlete sample can lead to sanctions. Legal status differs by country; in several jurisdictions it is not approved for human consumption and may be treated as an unapproved new drug.

SR9009 is a synthetic small molecule studied as an agonist of the nuclear receptors REV-ERBα and REV-ERBβ. It is not a steroid, peptide, or natural hormone. In scientific literature, it appears under the code SR9009 and in non-scientific contexts as Stenabolic. The compound was identified through chemical screening efforts aimed at targeting circadian clock components. Its status remains investigational, and no regulatory agency has approved it as a human medicine.

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SR9009 Background and Receptor Mechanism

Because REV-ERB receptors are core clock components, SR9009 has been examined for effects on daily rhythms as well as metabolism. Research has explored whether the compound can shift or reinforce circadian gene expression in tissues such as liver and muscle. Some studies report improved metabolic markers in obese or diabetic mice, while others show context-dependent responses. Questions remain about which effects are direct, which are secondary to timing, and how they might differ across species.

SR9009 is a synthetic small molecule studied as an agonist of REV-ERB nuclear receptors. REV-ERB alpha and REV-ERB beta help regulate circadian rhythms and metabolic gene expression. In laboratory research, SR9009 has been used to probe how these receptors affect skeletal muscle, liver, and adipose tissue. The compound was identified in academic drug-discovery work and is often described in scientific literature by its chemical name and research code. It is not an approved medicine, and human clinical data remain limited or absent.

Handling, Analysis, and Regulation

Regulatory treatment of SR9009 varies by country and context. It is not approved as a therapeutic drug by agencies such as the United States Food and Drug Administration or the European Medicines Agency. Sports authorities list it as a prohibited substance; the World Anti-Doping Agency classifies it among hormone and metabolic modulators. Legal status for personal possession or sale differs across jurisdictions, and some countries may restrict it under analog or research chemical laws. Buyers who seek verified material often rely on independent laboratory testing because online product labels may not match contents.

Laboratory samples of SR9009 are typically handled as research chemicals rather than pharmaceuticals. Suppliers usually state that the material is for research use only and not for human or veterinary administration. Storage recommendations generally call for a freezer at approximately −20 °C, protection from light, and a desiccated environment. The solid is often described as a white to off-white powder. Solubility is commonly reported in organic solvents such as dimethyl sulfoxide and ethanol, with low solubility in water.

Analytical identification and purity assessment often use high-performance liquid chromatography with ultraviolet detection or mass spectrometry. Liquid chromatography–tandem mass spectrometry is used to detect and quantify SR9009 in biological matrices, including urine and blood, for anti-doping or pharmacokinetic studies. Nuclear magnetic resonance spectroscopy can confirm molecular structure. Stability depends on form and storage: the solid is generally more stable than solutions, and repeated freeze–thaw cycles may degrade samples. Purity is typically reported as a percentage from a certificate of analysis.

Handling Storage and Quality Control

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.

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.

Background from the literature

== Mechanism of action == Ceftriaxone is a third-generation antibiotic from the cephalosporin family of antibiotics. It is within the β-lactam family of antibiotics. Ceftriaxone selectively and irreversibly inhibits bacterial cell wall synthesis by binding to transpeptidases, also called transamidases, which are penicillin-binding proteins (PBPs) that catalyze the cross-linking of the peptidoglycan polymers forming the bacterial cell wall. The peptidoglycan cell wall is made up of pentapeptide units attached to a polysaccharide backbone with alternating units of N-acetylglucosamine and N-acetylmuramic acid. PBPs act on a terminal D-alanyl-D-alanine moiety on a pentapeptide unit and catalyze the formation of a peptide bond between the penultimate D-alanine and a glycine unit on an adjacent peptidoglycan strand, releasing the terminal D-alanine unit in the process. The structure of ceftriaxone mimics the D-alanyl-D-alanine moiety, and the PBP attacks the beta-lactam ring in ceftriaxone as if it were its normal D-alanyl-D-alanine substrate. The peptidoglycan cross-linking activity of PBPs is a construction and repair mechanism that normally helps to maintain bacterial cell wall integrity, so the inhibition of PBPs leads to damage and destruction of the cell wall and eventually to cell lysis.

The generation of GSNO can serve as a stable and mobile NO pool which can effectively transduce NO signaling. Unlike other low molecular weight messengers that bind to and activate target cellular receptors, NO signaling is mediated by a coordinating complex between NO and transition metals or target cellular proteins, often via S-nitrosylation of cysteine residues. Studies suggest that NO metabolism has a significant role in human cardiovascular and respiratory diseases as well as in immune tolerance during organ transplantation.

=== Search and discussion === One of the central discussion forums was Reddit's /r/DarkNetMarkets/, which has been the subject of legal investigation, as well as the Tor-based discussion forum, The Hub. On March 21, 2018, Reddit administrators shut down the popular subreddit /r/DarkNetMarkets citing new changes to their content policy that forbids the sale of "Drugs, including alcohol and tobacco, or any controlled substances". This led to the rise of Dread, the dedicated darknet discussion forum and the news site Darknetlive (since closed). Some marketplaces maintain their own dedicated discussion forums and subreddits. The majority of the marketplaces are in English, but some have opened in Chinese, Russian, and Ukrainian. The dedicated market search engine Grams (closed December 2017) allowed the searching of multiple markets directly without login or registration. Dark web news and review sites such as the former DeepDotWeb, and All Things Vice provide exclusive interviews and commentary into the dynamic markets. Uptime and comparison services provide sources of information about active markets as well as suspected scams and law enforcement activity. Due to the decentralized nature of these markets, phishing and scam sites are often maliciously or accidentally referenced. After discovering the location of a market, a user must register on the site, sometimes with a referral link, after which they can browse listings. A further PIN may be required to perform transactions, better protecting users against login credential compromise.

=== Magnetic immunoassay === Magnetic immunoassay (MIA) is a novel type of diagnostic immunoassay utilizing magnetic nanobeads as labels in lieu of conventional, enzymes, radioisotopes or fluorescent moieties. This assay involves the specific binding of an antibody to its antigen, where a magnetic label is conjugated to one element of the pair. The presence of magnetic nanobeads is then detected by a magnetic reader (magnetometer) which measures the magnetic field change induced by the beads. The signal measured by the magnetometer is proportional to the analyte (virus, toxin, bacteria, cardiac marker, etc.) quantity in the initial sample.

Sources: en.wikipedia.org

Further detail

=== Polarization-resolved SHG === The advantages of polarimetry were coupled to SHG in 2002 by Stoller et al. Polarimetry can measure the orientation and order at molecular level, and coupled to SHG it can do so with the specificity to certain structures like collagen: polarization-resolved SHG microscopy (p-SHG) is thus an expansion of SHG microscopy. p-SHG defines another anisotropy parameter, as:

== Epidermolysis bullosa dystrophica == Epidermolysis bullosa dystrophica, also known as Dystrophic EB (DEB) is a chronic skin condition caused when anchoring fibrils are abnormal, diminished, or absent. This causes a weak dermoepidermal junction, where the epidermis easily separates from the dermis causing much pain. This condition is caused by a mutation of COL7A1, the gene that codes for a type of collagen 7.

=== Augmentation of Tumor Necrosis Factor === Injection of tuftsin intraperitoneally increases the formulation of TNF in serum and supernatants of cultured splenic and peritoneal adherent cells. This was also demonstrated in vitro using HL60 leukemia cells.

=== Pharmacokinetics === When administered together as dextromethorphan/bupropion, the elimination half-life of dextromethorphan is 22 hours and the elimination half-life of bupropion is 15 hours. The elimination half-lives of bupropion active metabolites are 35 hours for hydroxybupropion, 44 hours for erythrohydrobupropion, and 33 hours for threohydrobupropion. Bupropion inhibits the metabolism of dextromethorphan by inhibiting the enzyme CYP2D6, the major enzyme responsible for the metabolism of dextromethorphan. This in turn improves the bioavailability of dextromethorphan, prolongs its half-life, prevents its metabolism into dextrorphan, and increases the ratio of dextromethorphan to dextrorphan in the body.

=== February === 9 February – The Scottish Prison Service concludes its review of accommodating transgender prisoners, and recommends that transgender prisoners initially be accommodated according to their sex at birth while an individual assessment is carried out. 10 February – Following a legal challenge by lap dance performers and club owners, a ban on lap dancing clubs in Edinburgh, scheduled to come into force in April, is overturned by Edinburgh's Court of Session after it finds Edinburgh City Council acted illegally by voting to limit the number of sexual entertainment venues in the city from four to zero. 15 February – Nicola Sturgeon announces her resignation as First Minister of Scotland and Leader of the Scottish National Party after eight years in the role; she will stay on until her successor has been elected. 16 February – Deputy First Minister John Swinney rules himself out of the SNP leadership contest. 17 February – The Royal College of Nursing recommends its members accept a new pay offer of 6.5%. The offer from the Scottish Government also includes changes to conditions. 19 February Scottish Health Secretary Humza Yousaf and former Minister for Community Safety Ash Regan become the first two candidates to announce they will stand in the Scottish National Party leadership election. Keith Brown, the SNP's depute leader, Neil Gray, the Minister for International Development, and Màiri McAllan, the Environment Minister, all rule themselves out of the contest.

Sources: en.wikipedia.org

Supporting material

Lipoatrophy is the term describing the localized loss of fat tissue. This may occur as a result of subcutaneous injections of insulin in the treatment of diabetes, from the use of human growth hormone or from subcutaneous injections of copaxone used for the treatment of multiple sclerosis. In the latter case, an injection may produce a small dent at the injection site. Lipoatrophy occurs in HIV-associated lipodystrophy, one cause of which is an adverse drug reaction that is associated with some antiretroviral medications. A more general term for an abnormal or degenerative condition of the entire body's adipose tissue is lipodystrophy.

By using computational phylogenomic and structure predictions, experimental structural analyses, and cell biological assays, it was proposed that half of Goddard's structure is disordered and the other half is composed by alpha-helical amino acids. These analyses also indicated that Goddard's orthologs show similar results. Goddard's structure therefore appears to have been mainly conserved since its emergence. It has been proposed, that these four putative de novo genes have diverged beyond the point at which they can be found. However, the evidential strength of proposed "hidden homology" remains unclear since the study relies on very relaxed BLAST thresholds (high E-values/low identity, i.e. the "twilight zone") and on structural resemblance that could also reflect convergent evolution. Overall, de novo proteins are often short and enriched in intrinsically disordered regions (IDRs), and many are predicted to lack stable tertiary structure when isolated. However, comparative genome-wide analyses in rice suggest that the structural properties of de novo proteins can evolve rapidly in some lineages, with predicted decreases in disorder and increases in structured elements over short evolutionary timescales and incorporation of de novo proteins into heteromeric multimers. In Drosophila, a genome-wide study combining gene-age dating and structural modeling reported little overall predicted structural change among Drosophilinae de novo candidates, and ancestral sequence reconstruction suggested that many potentially well-folded candidates may be born well-folded.

=== Legal history === In 1997, three men from the Chicago area sued Hooters after being denied employment at an Orland Park, Illinois, restaurant. Each of them was awarded $19,100. Four men who filed a similar lawsuit in Maryland received $10,350 each. The settlement allows Hooters to continue gender-restricted hiring in its wait staff; the chain agreed to create other support jobs, like bartenders and hosts, that must be filled without regard to gender. In 2000, a federal jury ordered Hooters to pay $275,000 to former waitress Sara Steinhoff, who claimed in her lawsuit that she was the target of unwanted sexual advances, demeaning behavior and recrimination from managers while she worked at the Hooters in Newport, Kentucky, between October 1996 and October 1997. In 2001, a jury determined Hooters of Augusta Inc. willfully violated the Telephone Consumer Protection Act by sending unsolicited advertising faxes. The class-action lawsuit, brought in June 1995 by Sam Nicholson, included 1,320 others who said they received the advertising faxes from Hooters. Atlanta-based Hooters of America Inc., the local restaurant's parent company, paid out $11 million. The jury determined that six faxes were sent to each plaintiff. With a $500 fine for each, that amounts to a $3,000 award per plaintiff. Also in 2001, Jodee Berry, a waitress at a Hooters in Panama City Beach, Florida, won a beer sales contest, for which the promised prize was a new Toyota automobile. However, the manager awarded her a "toy Yoda" instead, claiming the contest was an April Fool's Day joke.

== Biosynthesis == To date, two distinct methods of biosynthesizing the β-lactam core of this family of antibiotics have been discovered. The first pathway discovered was that of the penams and cephems. This path begins with a nonribosomal peptide synthetase (NRPS), ACV synthetase (ACVS), which generates the linear tripeptide δ-(L-α-aminoadipyl)-L-cysteine-D-valine (ACV). ACV is oxidatively cyclized (two cyclizations by a single enzyme) to bicyclic intermediate isopenicillin N by isopenicillin N synthase (IPNS) to form the penam core structure. Various transamidations lead to the different natural penicillins.

== Treatment == IF tumors are commonly treated by surgical excision although in rare cases these tumors have recurred at the site of their removal. Recurrent tumors have been treated by repeated surgical excisions. Since IF tumors have not been reported to metastasize and no deaths have been attributed to it, long-term clinical observation without surgical intervention is a reasonable alternative to surgery, particularly for IF tumors that are neither uncomfortable, painful, or disfiguring.

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?

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.

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