circadian rhythm is one of those subjects where the details matter more than the headlines. This page pulls together the background, the mechanisms, and the practical points readers ask about most.
Last reviewed on 2025-09-06. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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 and metabolic gene expression. In laboratory experiments, SR9009 binds these receptors and alters transcription of genes involved in lipid handling, glucose metabolism, and mitochondrial function. It is not a naturally occurring compound and has no approved therapeutic use. Research interest stems from its ability to modify energy metabolism in cells and animal models.
Scientific discussion of SR9009 often separates animal evidence from human anecdote. Rodent studies provide controlled data on endurance, metabolism, and gene expression, but they use specific strains, doses, and treatment durations. Human reports are mostly uncontrolled and cannot establish cause and effect. Open questions include oral bioavailability, tissue distribution, metabolic stability, and long-term effects. Review articles generally call for more rigorous pharmacokinetic and safety research before any clinical use could be considered.
Analytical methods for SR9009 typically rely on liquid chromatography coupled with tandem mass spectrometry. The technique can separate the parent compound from related substances and detect low concentrations in biological matrices. Urine and blood are common samples in anti-doping testing, while in vitro studies may use cell culture media. Rapid metabolism and low expected concentrations make method validation important for reliable identification. Exact metabolite patterns can vary by species and are not fully mapped.
| 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 |
REV-ERB proteins typically suppress gene expression by recruiting corepressor complexes to DNA response elements. SR9009 binds these receptors and strengthens that repressive action in cell-based assays. Studies in rodents have reported changes in lipid handling, mitochondrial function, and exercise capacity after treatment. Such findings are often cited as evidence for metabolic effects, but species differences and limited pharmacokinetic data make direct translation to humans uncertain. Researchers continue to examine which effects are robust and which depend on specific experimental conditions.
SR9009 is frequently discussed alongside other REV-ERB ligands, including synthetic agonists and natural heme-related molecules. Its selectivity for REV-ERB over related nuclear receptors has been measured in binding and reporter assays, though off-target activity at higher concentrations is possible. The compound is prohibited in sport by the World Anti-Doping Agency, and it is not approved for any medical use in major jurisdictions. Products sold online may be labeled as research chemicals, and their identity and purity are not guaranteed by regulatory review.
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.
REV-ERB proteins help regulate daily cycles in gene expression, including genes tied to lipid and glucose metabolism. SR9009 binds these receptors and alters their activity in cell and animal experiments. Consequences observed in rodents include changes in skeletal muscle oxidative capacity, blood lipid levels, and exercise performance. The precise chain from receptor occupancy to whole-body effects is still an active area of study. Human responses cannot be assumed from rodent data.
SR9009 is not approved as a medicine by major regulatory agencies. It is commonly sold as a research chemical, a category that may fall outside customary drug approval and quality rules. In sports, the World Anti-Doping Agency lists SR9009 as a prohibited substance. Athletes who use it can face sanctions if it is detected in a sample. Legal status varies by country, and importation may be restricted. Enforcement practices differ across borders.
Detection of SR9009 in biological samples usually employs liquid chromatography coupled with tandem mass spectrometry. This method can identify the parent compound and sometimes metabolites in urine or blood. Because exposure can be low and clearance may be rapid, sample timing and limits of detection matter. Laboratories validate assays for sensitivity and specificity. Results are interpreted alongside chain-of-custody and quality-control records. Urine is the common matrix for anti-doping analysis, while blood may be used in research settings.
Handling recommendations for SR9009 in a laboratory setting include storing the solid at low temperature, protected from light and moisture. The compound is often dissolved in dimethyl sulfoxide or ethanol for experiments. Solutions should be prepared with appropriate personal protective equipment and disposed of according to local rules. Stability data for long-term storage are limited, so stock solutions are typically kept cold and used within defined periods. Records of preparation date and concentration support reproducibility.
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.
== Main applications == DMG-PEG 2000 has similar chemical properties to the phospholipids that make up the cell membrane. This enables lipid nanoparticles composed of it to easily merge with the cell membrane, delivering its contents.
Lipolysis, the removal of the fatty acid chains from the glycerol to which they are bound in their storage form as triglycerides (or fats), is carried out by lipases. These lipases are activated by high epinephrine and glucagon levels in the blood (or norepinephrine secreted by sympathetic nerves in adipose tissue), caused by declining blood glucose levels after meals, which simultaneously lowers the insulin level in the blood. Once freed from glycerol, the free fatty acids enter the blood, which transports them, attached to plasma albumin, throughout the body. Long-chain free fatty acids enter metabolizing cells (i.e. most living cells in the body except red blood cells and neurons in the central nervous system) through specific transport proteins, such as the SLC27 family fatty acid transport protein. Red blood cells do not contain mitochondria and are therefore incapable of metabolizing fatty acids; the tissues of the central nervous system cannot use fatty acids, despite containing mitochondria, because long-chain fatty acids (as opposed to medium-chain fatty acids) cannot cross the blood-brain barrier into the interstitial fluids that bathe these cells. Once inside the cell, long-chain-fatty-acid—CoA ligase catalyzes the reaction between a fatty acid molecule with ATP (which is broken down to AMP and inorganic pyrophosphate) to give a fatty acyl-adenylate, which then reacts with free coenzyme A to give a fatty acyl-CoA molecule.
=== Political trends and results === Several politicians have spent part of their lives in the city: Jules Lecesne (1818–1878), Jules Siegfried (1837–1922), and Félix Faure (1841–1899) were elected as municipal councillors and MPs. A pool, a shopping centre and a street have been named after René Coty from Le Havre, who served as President of the French Republic from 1954 to 1959. Christine Lagarde (born 1956) attended high schools in Le Havre before becoming Minister of the Economy and Director-General of the International Monetary Fund in 2011. Since 23 October 2010 the mayor has been Édouard Philippe (UMP). He also holds the presidency of the CODAH and has held a seat in the National Assembly for the 7th district of Seine-Maritime since 2012. He succeeded Antoine Rufenacht (UMP), who was mayor of Le Havre for fifteen years before resigning, as the head of the municipality. The city of Le Havre has long been the strongest bastion of the Communist Party of France, who directed it from 1956 to 1995. Overall, the inhabitants of Le Havre in the 7th electoral district (city centre and western neighbourhoods) tend to vote for the right while those of the 8th electoral district (eastern neighbourhoods) tend to choose the candidate of the left. For example, in the presidential election of 2007, the 7th electoral district voted for Nicolas Sarkozy (UMP) by 55.05% against 44.95% for Ségolène Royal (PS) while in the 8th electoral district 55.02% voted for the Socialist candidate.
The two substrates of this enzyme are (S)-carnitine and oxidised nicotinamide adenine dinucleotide (NAD+). Its products are 3-dehydrocarnitine, reduced NADH, and a proton. This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-OH group of donor with NAD+ or NADP+ as acceptor. The systematic name of this enzyme class is (S)-carnitine:NAD+ oxidoreductase.
=== Elimination === Small amounts of metabolites (alpha-methyldopa and alpha-methyldopamine) were found after the administration of both single-doses and maintenance-doses of AMPT. Small amounts of methyltyramine and alpha-methylnoradrenaline were found in patients undergoing AMPT therapy. Urine analysis also recovered 45 to 88 percent of unchanged AMPT after drug ingestion. Of the total AMPT excreted, 50 to 60 percent appeared in urine within the first 8 hours and 80 to 90 percent appeared within 24 hours of oral administration.
Sources: en.wikipedia.org
The active components of an RNA-induced silencing complex (RISC) are endonucleases called Argonaute proteins, which cleave the target mRNA strand complementary to their bound siRNA. As the fragments produced by Dicer are double-stranded, they could each in theory produce a functional siRNA. However, only one of the two strands, which is known as the guide strand, binds Argonaute and directs gene silencing. The other anti-guide strand or passenger strand is degraded during RISC activation. Although it was first believed that an ATP-dependent helicase separated these two strands, the process proved to be ATP-independent and performed directly by the protein components of RISC. However, an in vitro kinetic analysis of RNAi in the presence and absence of ATP showed that ATP may be required to unwind and remove the cleaved mRNA strand from the RISC complex after catalysis. The guide strand tends to be the one whose 5′ end is less stably paired to its complement, but strand selection is unaffected by the direction in which Dicer cleaves the dsRNA before RISC incorporation. Instead, the R2D2 protein may serve as the differentiating factor by binding the more-stable 5′ end of the passenger strand. The structural basis for binding of RNA to the Argonaute protein was examined by X-ray crystallography of the binding domain of an RNA-bound Argonaute.
== Narcotics == Narcotic analgesics decrease the painful sensations of serious injuries, potentially allowing athletes to continue training for competition after an injury. While some painkillers are allowed, including codeine, the following are banned in competition only:
=== Preadaptation model === The preadaptation model of de novo gene birth uses mathematical modeling to show that when sequences that are normally hidden are exposed to weak or shielded selection, the resulting pool of "cryptic" sequences (i.e. proto-genes) can be purged of "self-evidently deleterious" variants, such as those prone to lead to protein aggregation, and thus enriched in potential adaptations relative to a completely non-expressed and unpurged set of sequences. This revealing and purging of cryptic deleterious non-genic sequences is a byproduct of pervasive transcription and translation of intergenic sequences, and is expected to facilitate the birth of functional de novo protein-coding genes. This is because by eliminating the most deleterious variants, what is left is, by a process of elimination, more likely to be adaptive than expected from random sequences. Using the evolutionary definition of function (i.e. that a gene is by definition under purifying selection against loss), the preadaptation model assumes that "gene birth is a sudden transition to functionality" that occurs as soon as an ORF acquires a net beneficial effect. In order to avoid being deleterious, newborn genes are expected to display exaggerated versions of genic features associated with the avoidance of harm. This is in contrast to the proto-gene model, which expects newborn genes to have features intermediate between old genes and non-genes.
=== Women bodybuilders === The Cosmeticsurgery.com article They Need Bosoms, too – Women Weight Lifters (2013) reported that women weight-lifters have resorted to breast augmentation surgery to maintain a feminine physique, and so compensate for the loss of breast mass consequent to the increased lean-body mass and decreased body-fat consequent to lifting weights.
Sources: en.wikipedia.org
A less common form of cement is non-hydraulic cement, such as slaked lime (calcium oxide mixed with water), which hardens by carbonation in contact with carbon dioxide, which is present in the air (~ 412 vol. ppm ≃ 0.04 vol. %). First calcium oxide (lime) is produced from calcium carbonate (limestone or chalk) by calcination at temperatures above 825 °C (1,517 °F) for about 10 hours at atmospheric pressure:
== Structure == The structure of KLB was established by a combination of mass-spectrometry and NMR methods. Klebsazolicin is 23-aminoacid long peptide, containing four azoles (3 thiazoles and an oxazole) and an N-terminal lactamidine ring. The latter is formed by a linkage between two N-terminal amino acids (serine and glutamine) and is absolutely essential for bioactivity.
14 October – David Lammy becomes the first UK Foreign Secretary to attend a meeting of EU foreign ministers since Brexit as part of Labour's wish to "reset" the UK's relationship with the EU. Monarchists in Australia have criticised a decision by the country's state premieres to be absent from a reception held by Charles III when he visits the country later in the month, describing it as a snub. 16 October – The Assisted Dying Bill is introduced into Parliament, criticised by Archbishop of Canterbury Justin Welby as "dangerous" and a "slippery slope". 17 October – Former Conservative MP Craig Mackinlay is formally introduced into the House of Lords as Lord Mackinlay of Richborough. Now affectionately known as the 'bionic lord', he is the first quadruple amputee to sit in the Lords. 2024 Conservative Party leadership election: Conservative Party leadership candidates Robert Jenrick and Kemi Badenoch take part in a leadership debate on GB News, but Badenoch has turned down an invitation to take part in a Question Time special on BBC One, and a planned online debate organised by The Sun. 18 October – King Charles III and Queen Camilla arrive in Australia for their royal tour, Charles's first visit to the country since becoming King. 10 Downing Street says there will be no apology for the UK's role in the transatlantic slave trade when Charles III and Starmer attend the Commonwealth summit in Samoa. Former Daily Record editor Murray Foote announces he is standing down as chief executive of the SNP after 14 months in the post.
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.
No. It is an investigational compound without approved therapeutic indications. It is sold for research purposes only in many jurisdictions.