Semax 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 2026-04-07. Where a claim depends on a specific study, the study is described rather than over-claimed.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro. It was designed at the Institute of Molecular Genetics of the Russian Academy of Sciences as a structural analogue of tuftsin, a naturally occurring tetrapeptide fragment of the immunoglobulin heavy chain. The added Pro-Gly-Pro tail was intended to slow enzymatic degradation and extend biological activity. In Russia it is registered as an anxiolytic nasal preparation, while regulators elsewhere have not approved it for clinical use.
Proposed mechanisms centre on modulation of the GABAergic system, with reports of altered expression of genes related to GABA-A receptor subunits and changed monoamine turnover. Some studies describe inhibition of enkephalinase, the enzyme that degrades endogenous enkephalins, which may prolong opioid peptide signalling. Effects on brain-derived neurotrophic factor and on cytokine expression have also been reported. These findings come largely from animal models and small human studies, and the precise primary target remains unresolved.
Published clinical evidence is limited. Most controlled trials were conducted in Russia, enrolled modest numbers of participants, and appeared in Russian-language journals, which restricts independent verification. Reported outcomes include lower anxiety scores, improved attention and memory measures, and changes in fatigue ratings. Reviews written in English note methodological limitations such as small samples and inconsistent endpoints. Whether the compound produces clinically meaningful benefit relative to established anxiolytics is therefore an open question rather than an established finding.
Characterization of Selank in laboratory settings relies on standard peptide analytical techniques. Reverse-phase high-performance liquid chromatography separates the peptide from related impurities and degradation products, while mass spectrometry confirms molecular identity through accurate mass measurement. Amino acid analysis and peptide sequencing verify the primary structure when reference material is unavailable. Because Selank is a short chain, fragmentation-based analysis produces a diagnostic ion pattern that supports confident identification.
Peptide stability depends strongly on temperature, moisture, and pH. Lyophilized Selank is generally most stable when stored cold and dry, with freezer temperatures commonly used for long-term storage. In solution, the compound is susceptible to hydrolysis and to microbial growth if it is not handled aseptically. The C-terminal proline-rich extension appears to slow enzymatic cleavage relative to tuftsin, though quantitative degradation rates vary with the matrix and the conditions tested. Published stability data specific to Selank remain sparse.
Quality assessment of Selank samples typically combines purity determination with identity confirmation and counter-ion analysis. Purity is usually reported as a percentage by chromatographic area, with values above 95 percent often quoted for research-grade material. Water content and residual solvents are checked in lyophilized batches because they affect both stability and accurate mass determination. A reported purity figure does not by itself establish that a sample is the intended sequence, so orthogonal methods are needed to rule out sequence isomers or truncation products.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C33H57N11O9 | Free peptide form |
| Molecular mass | About 751.9 Da | Calculated average mass |
| Amino acid sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Single-letter form TKPRPGP |
| Structural basis | Tuftsin analogue | Extended version of a natural tetrapeptide |
| Development origin | Russian Academy of Sciences | Work carried out from the 1980s onward |
Development work on the compound began in the 1980s and 1990s at the Institute of Molecular Genetics in Moscow, within the same research programme that produced the peptide Semax. Early investigators sought a tuftsin derivative with improved resistance to enzymatic breakdown and with activity in the central nervous system after peripheral administration. Most of the primary literature from this period was published in Russian, a factor that still shapes how easily the findings can be checked by outside groups.
Naming for this compound is not fully standardised in English sources. The spelling Selanc appears in some transliterations, and catalogue entries may instead list the peptide sequence itself as the identifier. Reference material sometimes groups it with other short synthetic peptides studied for behavioural effects, which can create confusion when citations are compared. Distinguishing the exact sequence from related tuftsin analogues is therefore a practical first step when reviewing any dataset or specification sheet.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro. Its four N-terminal residues reproduce tuftsin, a tetrapeptide fragment of the immunoglobulin heavy chain, while the C-terminal Pro-Gly-Pro extension is a synthetic addition. The peptide has a molecular mass near 752 daltons and carries a net positive charge at physiological pH because of the arginine and lysine side chains. Published indexes list it under the name Selank and the sequence abbreviation TKPRPGP. Solid-phase peptide synthesis is the standard production route for research quantities.
Development took place at the Institute of Molecular Genetics of the Russian Academy of Sciences, where a series of short peptides were designed in the 1980s and 1990s. Selank was selected from variants of tuftsin that showed resistance to plasma peptidases. Russian regulatory approval covers it as an anxiolytic agent given intranasally. Outside that market the compound is normally handled as a research chemical rather than a medicine, and no widely recognised international pharmacopoeial monograph exists. The name Selank is a coined trade designation rather than a systematic chemical name.
Enzymatic stability motivates the extra three residues at the carboxyl end. Native tuftsin is cleaved quickly by circulating aminopeptidases and carboxypeptidases, which limits its duration of action and its usefulness as a tool compound. Extending the chain with proline-rich segments is a common design tactic because proline constrains the backbone and slows proteolysis. The same Pro-Gly-Pro motif appears in other Russian-developed peptides of the era. Whether the full seven-residue chain is required for activity, or whether it acts mainly as a prodrug releasing tuftsin, remains unresolved.
=== Moderate temperature plants === These plants prefer to grow at temperatures of 15 °C (59 °F) to 24 °C (75 °F) Others – Banksia marginata, Chinese Lanterns – Alkekengi, Clematis – Clematis, Cyclamen – Cyclamen persicum, Epacris impressa, Fuchsia – Fuchsia, Freesia – Freesia, Leucodendron, Love-in-a-Mist – Nigella damascena, Pansy – Viola x wittrockiana, Pelargonium, Primrose – Primula, Protea
Around 20–40% of those with coeliac disease experience non-responsive coeliac disease (NRCD), which is the continuation of symptoms despite elimination of gluten from their diets for at least 6 to 12 months. The most common cause of NRCD is unintentional gluten ingestion; however other conditions such as small intestinal bacterial overgrowth, giardiasis, disaccharide or FODMAP intolerance, Crohn's disease, fructose intolerance, microscopic colitis, pancreatic insufficiency, irritable bowel syndrome, and lactose intolerance can cause persistent symptoms or villous atrophy despite adhering to the GFD.
== Exercise-trained effects are mediated by epigenetic mechanisms == Between 2012 and 2019, at least 25 reports indicated a major role of epigenetic mechanisms in skeletal muscle responses to exercise. Epigenetic alterations often occur by adding methyl groups to cytosines in the DNA or removing methyl groups from the cytosines of DNA, especially at CpG sites. Methylations of cytosines can cause the DNA to be compacted into heterochromatin, thus inhibiting access of other molecules to the DNA. Epigenetic alterations also often occur through acetylations or deacetylations of the histone tails within chromatin. DNA in the nucleus generally consists of segments of 146 base pairs of DNA wrapped around eight tightly connected histones (and each histone also has a loose tail) in a structure called a nucleosome and one segment of DNA is connected to an adjacent DNA segment on a nucleosome by linker DNA. When histone tails are acetylated, they usually cause loosening of the DNA around the nucleosome, leading to increased accessibility of the DNA.
Sources: en.wikipedia.org
This same proposal was proposed again in 1976, but further studies indicated that the recurrence rate was not better. In 1888, treatments were tried that entered the abdomen to make reattachments. Some did not agree with this and suggested an approach through the inguinal canal. In 1898, further abdominal approaches were proposed. No further advances have been noted until 1961 when reattachment of the anterior vaginal wall to Cooper's ligament began to be used. Unfortunately, posterior vaginal wall prolapse occurred in some patients even though the anterior repair was successful. In 1955, using mesh to support pelvic structures became common. In 1970, tissue from pigs began to be used to strengthen the anterior vaginal wall in surgery. Beginning in 1976, improvement in suturing began along with the surgical removal of the vagina being used to treat prolapse of the bladder. In 1991, assumptions about the detailed anatomy of the pelvic support structures began to be questioned regarding the existence of some pelvic structures and the non-existence of others. More recently, stem cells and robot-assisted laparoscopic surgery have been used to treat cystoceles.
== Sources == Bulletins of the Information Bureau of the People's Union for the Defense of the Motherland and Freedom Savinkov, Boris. The Fight Against the Bolsheviks // Russian Foreign Literature. Anthology in Six Volumes. Moscow: Kniga, 1990. Vol. 1, Book 2. The Union for the Defense of the Homeland and Freedom and the Yaroslavl Rebellion of 1918 // Proletarian Revolution, 1923, no. 10. Klementyev, V. F. In Bolshevik Moscow (1918–1920). Moscow: Russkiy Put, 1998. Korovin, V. V.; Rusanov, E. P. Boris Savinkov's Case // History of the Soviet Union, 1967, no. 6, pp. 143–155. Golinkov, D. L. The Collapse of the Enemy Underground. Moscow, 1971. Gopper, Karl. Four Collapses: Memoirs of General Gopper. Riga, 1920. Jekabsons, E.; Ščerbinskis, V. Participation of Latvians in White Military Forces During the Russian Civil War 1917–1920. Riga: Journal of the Latvian Institute of History, 1997. Shentalinsky, Vitaly. "His Among His Own. Savinkov in the Lubyanka." New World, no. 7 (1996).
Eptifibatide (Integrilin, Millennium Pharmaceuticals, also co-promoted by Schering-Plough/Essex), is an antiplatelet drug of the glycoprotein IIb/IIIa inhibitor class. Eptifibatide is a cyclic heptapeptide derived from a disintegrin protein (P22827) found in the venom of the southeastern pygmy rattlesnake (Sistrurus miliarius barbouri). It belongs to the class of the arginine-glycine-aspartate-mimetics and reversibly binds to platelets. Eptifibatide has a short half-life. The drug is the third inhibitor of GPIIb/IIIa that has found broad acceptance after the specific antibody abciximab and the non-peptide tirofiban entered the global market.
Jack Watson was born on May 2, 1939, in Casey, Iowa, to Jesse H. and Anne Watson. Jack grew up in a town of about 1,000 residents in northern Iowa, Nora Springs. His father was the area's school superintendent and he had one brother. After graduating from Nora Springs High School 1957, he went to Iowa State University, majoring in chemistry and taking part in the University’s Air Force ROTC program for four years which accounts for the four years he spent on active duty in California and Texas. Before serving his Air Force obligation, after graduation Iowa State with a degree in Chemical Technology in 1961, he went to graduate school at the Massachusetts Institute Technology (MIT). At MIT, Watson was a PhD candidate in the laboratory of Klaus Biemann, one of the most notable experts in organic mass spectrometry at the time. As soon as he graduated from MIT, Watson reported for duty in the United States Air Force in the San Francisco Bay area. A friend of his from high school, introduced Watson to Judith Sjoberg. Not long after that, they were married and moved to Brooks Air Base in San Antonio, Texas. After completing his tour of duty in the Air Force, Watson took a one-year postdoctoral position in Strasbourg France at the Institut de Chimie, Université de Strasbourg under the direction of Robert Wolf. During this time and through the licensing of the Watson-Biemann gas separator to Thomson-CSF, for use in a gas chromatograph-mass spectrometer they ware manufacturing at the time, Watson made everlasting ties to the French Mass Spectrometry community.
Sources: en.wikipedia.org
It is a seven-amino-acid peptide, Thr-Lys-Pro-Arg-Pro-Gly-Pro, produced by chemical synthesis rather than extracted from biological tissue. Its design is based on tuftsin, a natural immunomodulatory tetrapeptide. The C-terminal Pro-Gly-Pro segment is a common stabilising motif in short regulatory peptides.
The core four residues correspond to tuftsin, which occurs naturally as part of immunoglobulin G. The full seven-residue sequence, however, is not a known endogenous peptide. It is a laboratory-designed analogue intended to combine tuftsin-like activity with greater resistance to breakdown.
No single receptor has been confirmed as the primary target. Reports describe involvement of the GABAergic system, interference with enkephalin degradation, and shifts in neurotrophic factor expression. Because these observations come from different models and assays, they have not yet been integrated into one accepted mechanism.
The most common approach combines reverse-phase liquid chromatography with mass spectrometry. Chromatography separates the components while mass spectrometry confirms the molecular mass. Peptide sequencing or tandem mass analysis can further verify the amino acid order.