A practical reference on circadian rhythm: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
This page was last updated on 2026-03-17 and is reviewed periodically as new material appears.
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.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic small-molecule REV-ERB agonist | Not a hormone or natural product |
| Primary targets | REV-ERBα and REV-ERBβ | Nuclear receptors involved in circadian and metabolic regulation |
| Appearance | White to off-white solid | Typical for purified research samples |
| Solubility | Soluble in DMSO and ethanol; low water solubility | Laboratory solubility depends on solvent and purity |
| Common synonyms | SR9009; Stenabolic | Stenabolic is a colloquial name, not a formal chemical name |
Mechanistically, SR9009 binds the ligand-binding domain of REV-ERBα/β and enhances recruitment of corepressor complexes. This represses target genes rather than activating them. Because REV-ERB proteins normally compete with ROR proteins at shared response elements, the net effect depends on tissue and timing. Researchers use SR9009 to probe how nuclear receptor signaling links the clock to metabolism, inflammation, and muscle biology. Findings are largely preclinical, and the precise contribution of each receptor subtype remains under study.
SR9009 is frequently discussed in fitness and research-chemical contexts, yet it has no approved medical indication. Regulatory agencies have not authorized it for human use, and it is not a standard prescription drug. Some sports organizations list it as a prohibited substance because of its potential performance-enhancing properties. Published human data are sparse, so claims about its effects in people often rely on animal models or anecdotal reports. Quality and identity of online materials can vary widely.
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.
Puffballs are a type of fungus featuring a ball-shaped fruiting body that, when mature, bursts on contact or impact, releasing a cloud of dust-like spores into the surrounding area. Puffballs belong to the division Basidiomycota and encompass several genera, including Calvatia, Calbovista and Lycoperdon. The puffballs were previously treated as a taxonomic group called the Gasteromycetes or Gasteromycetidae, but they are now known to be a polyphyletic assemblage. The distinguishing feature of all puffballs is that they do not have an open cap with spore-bearing gills. Instead, spores are produced internally, in a spheroidal fruit body called a gasterothecium (gasteroid 'stomach-like' basidiocarp). As the spores mature, they form a mass called a gleba in the centre of the fruitbody that is often of a distinctive color and texture. The basidiocarp remains closed until after the spores have been released from the basidia. Eventually, it develops an aperture, or dries, becomes brittle, and splits, and the spores escape. The spores of puffballs are statismospores rather than ballistospores, meaning they are not forcibly extruded from the basidium. Puffballs and similar forms are thought to have evolved convergently (that is, in numerous independent events) from Hymenomycetes by gasteromycetation, through secotioid stages. Thus, 'Gasteromycetes' and 'Gasteromycetidae' are now considered to be descriptive, morphological terms (more properly gasteroid or gasteromycetes, to avoid taxonomic implications) but not valid cladistic terms.
=== Biological role === Nicotinamide occurs as a component of a variety of biological systems, including within the vitamin B family and specifically the vitamin B3 complex. It is also a critically important part of the structures of NADH and NAD+, where the N-substituted aromatic ring in the oxidised NAD+ form undergoes reduction with hydride attack to form NADH. The NADPH/NADP+ structures have the same ring, and are involved in similar biochemical reactions. Nicotinamide can be methylated in the liver to biologically inactive 1-methylnicotinamide when there are sufficient methyl donors.
==== Acupuncture and other interventions ==== While acupuncture leads to improvements in pain relief, this improvement is small and may be of questionable importance. Waiting list–controlled trials for peripheral joint osteoarthritis do show clinically relevant benefits, but these may be due to placebo effects. Acupuncture does not seem to produce long-term benefits. Electrostimulation techniques such as TENS have been used to treat osteoarthritis in the knee. However, there is no conclusive evidence to show that it reduces pain or disability. A Cochrane review of low-level laser therapy found unclear evidence of benefit, whereas another review found short-term pain relief for osteoarthritic knees. Further research is needed to determine if balneotherapy for osteoarthritis (mineral baths or spa treatments) improves a person's quality of life or ability to function. There is low-quality evidence that therapeutic ultrasound may be beneficial for people with osteoarthritis of the knee; however, further research is needed to confirm and determine the degree and significance of this potential benefit. Therapeutic ultrasound is safe and reduces pain and improves physical function in knee osteoarthritis. While phonophoresis does not improve functions, it may offer greater pain relief than standard non-drug ultrasound. There is weak evidence suggesting that electromagnetic field treatment may result in moderate pain relief; however, further research is necessary, and it is not known if electromagnetic field treatment can improve quality of life or function.
This need for NADH in anabolism poses a problem for prokaryotes growing on nutrients that release only a small amount of energy. For example, nitrifying bacteria such as Nitrobacter oxidize nitrite to nitrate, which releases sufficient energy to pump protons and generate ATP, but not enough to produce NADH directly. As NADH is still needed for anabolic reactions, these bacteria use a nitrite oxidoreductase to produce enough proton-motive force to run part of the electron transport chain in reverse, generating NADH.
== Sports == Canberra Raiders, Australian rugby league football club Chitwan Rhinos, a professional Twenty20 cricket franchise representing Chitwan District, Nepal in the Nepal Premier League (NPL) Colorado Rockies, a Major League Baseball team Cincinnati Reds, another Major League Baseball team Colorado Rockies (NHL), a former National Hockey League team Cristiano Ronaldo, Portuguese footballer Commonwealth record in athletics Commonwealth record in swimming
Sources: en.wikipedia.org
Israel has used Palestinian children as human shields in Gaza in violation of Geneva conventions. Human rights groups have said that "even if Hamas were using human shields", Israel must still abide by international law, especially the principle of proportionality. In May 2023, before the beginning of the Gaza war, Defence for Children International – Palestine (DCIP) had already documented that five children had been used as human shields by the Israeli army since the beginning of that year, with two of the victims being 2-year-old twins. According to a 2024 Haaretz investigation based on many Israeli soldiers' testimony, Palestinian teenagers, adults, and occasionally elderly men are regularly used as human shields to explore the tunnel network in the Gaza Strip. These shawashim are dressed up, apart from sandshoes, to look like Israeli soldiers, handcuffed, blindfolded and, with a video camera attached to their bodies, sent into houses where Hamas combatants are suspected to hide, or into tunnels that might be booby-trapped. The practice is said to be widely known to IDF field commanders. Palestinians were used when neither sniffer dogs nor drones were available. An October 2024 investigation by CNN found that while the scale and scope of the practice was unknown, testimony from civilians and an Israeli soldier showed Israel's use of Palestinians as human shields was widespread across the Gaza Strip.
== Morphology == An animal's hump is formed by neural spines on the thoracic vertebrae. Despite only being known from the fossil record, the woolly mammoth and species of the genus Titanotylopus are assumed to have had humps due to the presence of such spines in their skeletons. In the gaur, the hump is formed solely because of the skeletal structure, as its third to eleventh vertebrae have such spines. In both dromedaries and bactrian camels, humps are attached to the adipose tissue in the dorsal region, and fixed in place by the trapezius and rhomboid muscles.
==== Ergolines (non-selective monoamine receptor modulators) ==== Dihydroergotamine (DHE; INP-104; POD-DHE; Trudhesa) – non-selective monoamine receptor modulator and ergoline – migraine [128] Dihydroergotamine mesilate intranasal (Atzumi; STS-101; TO-2070) – non-selective monoamine receptor modulator and ergoline – migraine [129] Dihydroergotamine mesylate intranasal (Migranal) – non-selective monoamine receptor modulator and ergoline – migraine [130]
==== By phosphate ==== In cyanobacteria, inorganic phosphate (Pi) also participates in the co-ordinated regulation of photosynthesis: Pi binds to the RuBisCO active site and to another site on the large chain where it can influence transitions between activated and less active conformations of the enzyme. In this way, activation of bacterial RuBisCO might be particularly sensitive to Pi levels, which might cause it to act in a similar way to how RuBisCO activase functions in higher plants.
Sources: en.wikipedia.org
It is a synthetic research compound that activates REV-ERB nuclear receptors. It is not an approved drug or dietary supplement. Most information comes from cell and animal studies.
It binds REV-ERBα and REV-ERBβ and changes transcription of metabolic genes. This can affect circadian rhythm, lipid use, and mitochondrial function. The full downstream effects are still under study.
No. Some rodent studies show increased endurance, but controlled human trials are lacking. Claims about human performance are not established by published evidence.
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.