NR1D2 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.
Updated 2026-07-15. Numbers and descriptions here follow the published literature rather than marketing material.
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.
The mechanism of action involves binding to REV-ERB receptors and recruiting corepressor complexes, which represses target gene transcription. This contrasts with many nuclear receptor agonists that activate transcription. Downstream effects may include changes in autophagy, mitochondrial biogenesis, and lipid handling, but the precise pathways remain an active area of study. Whether these molecular events translate into meaningful physiological effects in humans is unresolved. Most evidence comes from cultured cells and rodent models rather than human participants.
SR9009 is a synthetic small molecule studied as a REV-ERB agonist. REV-ERBα and REV-ERBβ are nuclear receptors that help regulate circadian rhythms and metabolic gene expression. The compound was identified in academic screening efforts to find synthetic ligands for these receptors. In cell and animal studies, SR9009 alters transcription of genes involved in lipid and glucose metabolism, and it can shift circadian behavior. It is not an approved therapeutic agent.
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.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic REV-ERB agonist | Small molecule; not a steroid or peptide. |
| Primary targets | NR1D1 and NR1D2 | Also known as REV-ERBα and REV-ERBβ. |
| Studied routes | Intraperitoneal in rodents | Oral bioavailability in humans is not established. |
| Human approval | No approved therapeutic indication | No recognized clinical use. |
| Key uncertainty | Human physiological effects | Preclinical findings may not translate. |
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.
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.
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.
==== Replication ==== repA: Initiates replication at the origin of replication (oriV), which helps it control plasmid copy number. copA: regulates repA mRNA translation by using an antisense RNA, controlling the frequency of replication. copB: contributes to the control of copy numbers by acting as a repressor protein that inhibits RepA transcription. oriV: origin of replication. RepA is needed in order to initiate replication.
==== Open Roof Deformity ==== Reduction of a dorsal hump may involve bone (upper vault) and/or cartilage (middle vault). When the bony dorsum (eg, nasal bone) is reduced, there may be a resulting gap in the middle of the nasal bones. This is typically corrected intraoperatively with lateral osteotomies to narrow the nasal bones and remove the gap. However, if the gap is not corrected, then an open roof deformity may result.
The two substrates of this enzyme are D-glucose and oxidised nicotinamide adenine dinucleotide phosphate (NADP+). Its products are glucono-δ-lactone, reduced NADPH, 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 D-glucose:NADP+ 1-oxidoreductase. Other names in common use include nicotinamide adenine dinucleotide phosphate-linked aldohexose, dehydrogenase, NADP+-linked aldohexose dehydrogenase, NADP+-dependent glucose dehydrogenase, and glucose 1-dehydrogenase (NADP+).
Sources: en.wikipedia.org
=== Diabetes === Januvia (sitagliptin) ($1.3 billion in 2024 revenues) is a dipeptidyl peptidase IV inhibitor for the treatment of type 2 diabetes. In 2013, Januvia was the second largest selling diabetes drug worldwide. It has been popular due in part because unlike many other diabetes drugs, it causes little or no weight gain and is not associated with hypoglycemic episodes. There has been some concern that treatment with Januvia and other DPP-IV inhibitors may be associated with a modestly increased risk of pancreatitis. Janumet ($1.0 billion in 2024 revenues) is a single pill combination drug containing both Januvia and metformin.
coli bacteria stores proteins and pyrophosphates in its periplasmic membrane until either are needed within the cell. Recent advancement in phosphoproteomic identification has resulted in the discoveries of countless phosphorylation sites in proteins. This required an integrative medium for accessible data in which known phosphorylation sites of proteins are organized. A curated database of dbPAF was created, containing known phosphorylation sites in H. sapiens, M. musculus, R. norvegicus, D. melanogaster, C. elegans, S. pombe and S. cerevisiae. The database currently holds 294,370 non-redundant phosphorylation sites of 40,432 proteins. Other tools of phosphorylation prediction in proteins include NetPhos for eukaryotes, NetPhosBac for bacteria, and ViralPhos for viruses.
Pepsin is one of the primary causes of mucosal damage during laryngopharyngeal reflux. Pepsin remains in the larynx (pH 6.8) following a gastric reflux event. While enzymatically inactive in this environment, pepsin would remain stable and could be reactivated upon subsequent acid reflux events. Exposure of laryngeal mucosa to enzymatically active pepsin, but not irreversibly inactivated pepsin or acid, results in reduced expression of protective proteins and thereby increases laryngeal susceptibility to damage. Pepsin may also cause mucosal damage during weakly acidic or non-acid gastric reflux. Weak or non-acid reflux is correlated with reflux symptoms and mucosal injury. Under non-acid conditions (neutral pH), pepsin is internalized by cells of the upper airways such as the larynx and hypopharynx by a process known as receptor-mediated endocytosis. The receptor by which pepsin is endocytosed is currently unknown. Upon cellular uptake, pepsin is stored in intracellular vesicles of low pH at which its enzymatic activity would be restored. Pepsin is retained within the cell for up to 24 hours. Such exposure to pepsin at neutral pH and endocyctosis of pepsin causes changes in gene expression associated with inflammation, which underlies signs and symptoms of reflux, and tumor progression. This and other research implicates pepsin in carcinogenesis attributed to gastric reflux. Pepsin in airway specimens is considered to be a sensitive and specific marker for laryngopharyngeal reflux.
Sources: en.wikipedia.org
Many species, varieties and cultivars are grown in gardens for their ornamental flowers. In horticulture the term pansy is normally used for those multi-colored, large-flowered cultivars which are raised annually or biennially from seed and used extensively in bedding. The terms viola and violet are normally reserved for small-flowered annuals or perennials, including the wild species. Cultivars of Viola cornuta, Viola cucullata, and Viola odorata, are commonly grown from seed. Other species often grown include Viola labradorica, Viola pedata, and Viola rotundifolia. The modern garden pansy (V. × wittrockiana) is a plant of complex hybrid origin involving at least three species, V. tricolor (wild pansy or heartsease), V. altaica, and V. lutea (mountain pansy). The hybrid horned pansy (V. × williamsii) originates from hybridization involving garden pansy and Viola cornuta.
for an n electron process. Focusing on current, reversible couples are characterized by ipa/ipc = 1. When a reversible peak is observed, thermodynamic information in the form of a half cell potential E01/2 can be determined. When waves are semi-reversible (ipa/ipc is close but not equal to 1), it may be possible to determine even more specific information (see electrochemical reaction mechanism). The current maxima for oxidation and reduction itself depend on the scan rate, see the figure.
=== Comparing PAM and BLOSUM === Although the PAM log-odds matrices were the first scoring matrices used with BLAST, the PAM matrices have largely been replaced by the BLOSUM matrices. Although both matrices produce similar scoring outcomes they were generated using differing methodologies. The BLOSUM matrices were generated directly from the amino acid differences in aligned blocks that have diverged to varying degrees the PAM matrices reflect the extrapolation of evolutionary information based on closely related sequences to longer timescales. Since scoring information for the PAM and BLOSUM matrices were generated in very different ways the numbers associated with the matrices have fundamentally different meanings; the numbers for PAM matrices increase for comparisons among more divergent proteins whereas the numbers for the BLOSUM matrices decrease. However, all amino acid substitution matrices can be compared in an information theoretic framework using their relative entropy.
== Diagonals == If e, f, g and h are the tangent lengths from A, B, C and D respectively to the points where the incircle is tangent to the sides of a tangential quadrilateral ABCD, then the lengths of the diagonals p = AC and q = BD are
Sources: en.wikipedia.org
It is a synthetic compound that acts as an agonist at REV-ERBα and REV-ERBβ. It is used mainly as a research chemical to study circadian and metabolic pathways. It is not approved for human therapeutic use.
REV-ERB receptors generally repress transcription when bound by natural heme. SR9009 is described as an agonist that enhances this repressive activity. The result is altered expression of clock and metabolic genes.
Published controlled human trials are lacking. Some sources cite limited or unofficial reports, but these do not establish safety or efficacy. Claims about human performance effects remain unverified.
SR9009 is a synthetic compound investigated as an agonist of the nuclear receptors REV-ERBα and REV-ERBβ. It is used in preclinical research on circadian rhythm and metabolism. It is not an approved drug.