circadian rhythm comes up often in conversation and rarely with the context attached. Here we lay out the basics in order, then work through the practical considerations.
Last reviewed on 2025-07-31. Where a claim depends on a specific study, the study is described rather than over-claimed.
SR9009 is a synthetic small molecule studied as an agonist of the nuclear receptors REV-ERBα and REV-ERBβ, also called NR1D1 and NR1D2. These receptors help regulate circadian rhythms and metabolic gene programs. The compound was developed for laboratory research, not as an approved therapeutic. Its identity is distinct from steroid hormones and selective androgen receptor modulators. Scientific interest centers on how REV-ERB activation changes gene expression in cells and animal models.
At the molecular level, SR9009 binds the ligand-binding domain of REV-ERB and strengthens recruitment of corepressor proteins such as NCoR and HDAC3. This increases repression of target genes, including Bmal1 and other clock-controlled and metabolic genes. In rodent studies, such changes have been linked to altered lipid handling, glucose metabolism, and energy expenditure. The precise chain of events between receptor binding and whole-body effects remains an active area of research. Findings in animals do not automatically translate to humans.
Laboratory studies often administer SR9009 by injection because oral absorption appears poor in rodents. Reported pharmacokinetic properties include rapid metabolism and low systemic exposure after oral dosing. Human pharmacokinetic data are sparse, so absorption, distribution, metabolism, and excretion in people are not well defined. Some research explores related REV-ERB compounds with improved drug-like properties. Regulatory approval for any REV-ERB agonist as a human medicine has not been granted to date.
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.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic small molecule | Studied as a REV-ERB agonist |
| Molecular formula | C20H24ClN3O4S | Reported for the neutral compound |
| Appearance | Off-white to pale yellow solid | Typical research-grade material |
| Solubility | Sparingly soluble in water | Soluble in solvents such as DMSO |
| Common synonyms | SR9009; Stenabolic | Stenabolic is an informal alias |
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.
SR9009 binds REV-ERB receptors and alters their repressive activity on target genes. This action can change transcription of genes involved in lipid handling, glucose metabolism, and mitochondrial function. In rodent studies, treated animals have shown changes in muscle oxidative capacity and exercise performance, though effects vary by dose, duration, and model. The precise molecular steps connecting receptor binding to whole-body outcomes are still an active area of investigation. Findings in animals do not automatically translate to humans.
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.
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.
=== Holly Newman === Holly Newman (Anna Wilson-Jones) is the widow of Eric's first boss and mentor, Newman. She and Eric were in a relationship while working as junior associates in New York, but Holly began an affair with Newman and later married him. She and Eric reconnect after Newman's death when Eric visits the New York office, and Eric secretly cheats on his wife with Holly before flying back to London.
== Ecology == Many cnidarians are limited to shallow waters because they depend on endosymbiotic algae for much of their nutrients. The life cycles of most have polyp stages, which are limited to locations that offer stable substrates. Nevertheless, major cnidarian groups contain species that have escaped these limitations. Hydrozoans have a worldwide range: some, such as Hydra, live in freshwater; Obelia appears in the coastal waters of all the oceans; and Liriope can form large shoals near the surface in mid-ocean. Among anthozoans, a few scleractinian corals, sea pens and sea fans live in deep, cold waters, and some sea anemones inhabit polar seabeds while others live near hydrothermal vents over 10 km (33,000 ft) below sea-level. Reef-building corals are limited to tropical seas between 30°N and 30°S with a maximum depth of 46 m (151 ft), temperatures between 20 and 28 °C (68 and 82 °F), high salinity, and low carbon dioxide levels. Stauromedusae, although usually classified as jellyfish, are stalked, sessile animals that live in cool to Arctic waters. Cnidarians range in size from a mere handful of cells for the parasitic myxozoans through Hydra's length of 5–20 mm (1⁄4–3⁄4 in), to the lion's mane jellyfish, which may exceed 2 m (6 ft 7 in) in diameter and 75 m (246 ft) in length. Prey of cnidarians ranges from plankton to animals several times larger than themselves. Some cnidarians are parasites, mainly on jellyfish but a few are major pests of fish. Others obtain most of their nourishment from endosymbiotic algae or dissolved nutrients.
=== Mac port === A version of Half-Life for Mac OS was announced by Logicware on April 23, 1999. However, Valve canceled it a few months later in October 1999. The Valve CEO, Gabe Newell, said the port was substandard, citing a separate multiplayer network, no automatic update utility and the inability to include Valve's multiplayer mod Team Fortress Classic. He said he did not want to make Mac players "second-class customers" and preferred to write off the investment rather than "take money from Mac customers and short-change them". Rebecca Heineman, the co-founder of Logicware, denied this, saying that Valve cancelled the port as Apple had angered them by misrepresenting sales projections. She said the port was complete and three weeks from release. In 2013, Valve released a port for OS X.
Sources: en.wikipedia.org
== Treatment == Supportive care in those with PAH involves using diuretics as needed for fluid overload, supplemental oxygen for hypoxemia, following a low sodium diet, an exercise program (such as walking), and routine immunizations. Vasoconstricting medications (frequently found in cough, cold and sinus formulations) should be avoided. Cardiopulmonary rehabilitation programs may be used for symptom control, patient education and counselling. Anticoagulation, once universally used for PAH, is now indicated in idiopathic PAH, and its use is evaluated based on patient factors. Disease specific therapy for PAH has improved disease free survival, symptom scores and mortality. Treatments consist of targeting the various aberrant pathways involved in the disease. For those with moderate to severe disease, dual therapy targeting at least 2 different disease specific pathways is indicated. Dual therapy is associated with greater mortality and disease free survival benefits over monotherapy. PDE5 inhibitors (including sildenafil and tadalafil are used to dilate blood vessels by inhibiting the degradation of Cyclic guanosine monophosphate (cGMP). cGMP inhibits pulmonary artery smooth muscle proliferation and causes pulmonary artery smooth muscle cell relaxation, thus acting as a vasodilator. Riociguat also causes vasodilation by stimulating cGMP production. Endothelin receptor antagonists cause vasodilation as well by blocking the action of the potent vasoconstrictor and vascular smooth muscle cell proliferation activator endothelin-1.
=== Biochemistry === Guanidine exists protonated, as guanidinium, in solution at physiological pH. Guanidinium chloride (also known as guanidine hydrochloride) has chaotropic properties and is used to denature proteins. Guanidinium chloride is known to denature proteins with a linear relationship between concentration and free energy of unfolding. In aqueous solutions containing 6 M guanidinium chloride, almost all proteins lose their entire secondary structure and become randomly coiled peptide chains. Guanidinium thiocyanate is also used for its denaturing effect on various biological samples. Recent studies suggest that guanidinium is produced by bacteria as a toxic byproduct. To alleviate the toxicity of guanidinium, bacteria have developed a class of transporters known as guanidinium exporters or Gdx proteins to expel the extra amounts of this ion to the outside of the cell. Gdx proteins are highly selective for guanidinium and mono-substituted guanidinyl compounds and share an overlapping set of non-canonical substrates with drug exporter EmrE.
=== Hu-SRC-scid model === The humanized severe combined immunodeficiency (SCID) mouse model, also known as the hu-SRC-scid model, has been extensively utilized in various research areas, including immunology, infectious diseases, cancer, and drug development. This model has been instrumental in studying the human immune response to xenogeneic and allogeneic decellularized biomaterials, providing valuable insights into the biocompatibility and gene expression regulation of these materials. Hu-SRC-scid mice are developed by engrafting CD34+ human hematopoietic stem cells into immunodeficient mice. The cells are obtained from human fetal liver, bone marrow or from blood derived from the umbilical cord, and engrafted via intravenous injection. The advantages of this model are that it offers multilineage development of hematopoietic cells, generation of a naïve immune system, and if engraftment is carried out by intrahepatic injection of newborn mice within 72 hours of birth, it can lead to enhanced human cell reconstitution. Nevertheless, limitations associated with the model are that it takes a minimum of 10 weeks for cell differentiation to occur, it harbors low levels of human RBCs, polymorphonuclear leukocytes, and megakaryocytes.
Sources: en.wikipedia.org
SR9009 is a synthetic research compound that activates the REV-ERBα and REV-ERBβ nuclear receptors. It is not an approved drug and has no established human therapeutic use. Most published biological data come from cell and rodent studies.
No. SR9009 is frequently mislabeled as a SARM in online discussions, but it does not target androgen receptors. Its known mechanism involves REV-ERB nuclear receptors and circadian-metabolic gene regulation.
Human clinical data are very limited. There is no approved human use, and safety and efficacy in people are not established. Most evidence comes from preclinical models, so effects observed in animals may not apply to humans.
Liquid chromatography-tandem mass spectrometry is a common approach. It can detect the parent compound and its metabolites in biological matrices.