Everything below concerns Semax. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Updated 2025-09-05. Numbers and descriptions here follow the published literature rather than marketing material.
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, frequently abbreviated as TKPRPGP. It was designed as a structural analogue of tuftsin, a naturally occurring tetrapeptide released by enzymatic cleavage of the immunoglobulin heavy chain. The two additional proline residues at the C-terminal end extend the parent chain and change how the molecule behaves in solution. The free peptide has a calculated molecular mass of approximately 751.9 g/mol and is generally supplied as a lyophilised white to off-white powder.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic heptapeptide | Tuftsin analogue |
| Sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Single-letter form: TKPRPGP |
| Molecular formula | C33H57N11O9 | Calculated for the free peptide |
| Molecular weight | About 751.9 g/mol | Derived from the sequence |
| Appearance | White to off-white powder | Typical lyophilised form |
Selank is studied chiefly as an animal-model anxiolytic with proposed secondary effects on memory and immune signaling. Reported mechanisms include modulation of the GABA-A receptor complex, inhibition of enkephalin-degrading enzymes, and shifts in monoamine turnover within limbic structures. Some experiments describe increased expression of brain-derived neurotrophic factor in the hippocampus after repeated dosing. No single molecular target has been confirmed, and the peptide does not bind any receptor with the selectivity typical of a conventional small-molecule drug. Mechanism therefore remains a set of hypotheses rather than an established pathway.
Laboratory work relies on standard behavioral paradigms. Rodents are tested in the elevated plus maze, open field, and passive avoidance tasks, with outcomes compared against diazepam or vehicle controls. Intranasal dosing is used most often because it bypasses first-pass metabolism, though intraperitoneal and intravenous routes also appear in published protocols. Biochemical endpoints include tissue BDNF concentrations, cytokine levels, and monoamine metabolites. Human data are limited to small Russian trials reporting reduced anxiety scores; most were not prospectively registered, and few employed independent outcome assessment.
Selank is a synthetic heptapeptide developed in Russia. Its sequence is Thr-Lys-Pro-Arg-Pro-Gly-Pro, a seven-residue chain built around the natural tetrapeptide tuftsin. Researchers at the Institute of Molecular Genetics of the Russian Academy of Sciences first described the compound in the mid-1990s. The design combined the tuftsin core with an added Pro-Gly-Pro tail, a modification intended to extend the molecule's stability in biological fluids. Published work on the peptide has appeared mainly in Russian-language journals.
Reported activity for Selank centers on anxiolytic and nootropic effects. Russian clinical reports describe use in anxiety and in cognitive or attention-related complaints. Most of this evidence comes from studies conducted by the same research groups that developed the peptide. Independent replication in other countries remains limited, and no major Western regulatory agency has approved the compound for any indication. The gap between local reports and external verification is a recurring point in discussions of the peptide.
Tuftsin, the parent structure, is a naturally occurring immunomodulatory tetrapeptide released from the Fc region of immunoglobulin G by spleen enzymes. Selank extends this four-residue sequence with three additional amino acids. The stated rationale is that the added tail slows enzymatic breakdown and may influence receptor interactions. How the full heptapeptide behaves at the molecular level is not firmly established, and proposed mechanisms often involve indirect modulation of neurotransmitter or immune signaling rather than a single defined target.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro. It was designed as a stabilized analogue of tuftsin, a naturally occurring tetrapeptide fragment derived from the immunoglobulin heavy chain. The additional Pro-Gly-Pro segment at the carboxyl terminus is intended to slow enzymatic cleavage. The compound is usually described in the literature as a synthetic peptide with anxiolytic and cognitive-related activity, a label that reflects a research context rather than an approved therapeutic category.
Most published work on selank originates from a small number of research groups in the Russian Federation. A large share of that record appears in Russian-language journals, which limits access for readers who rely on English-indexed databases. Independent replication by laboratories outside the original research network is sparse in publicly available sources. This concentration of origin and language is a frequently noted feature when the compound is summarized in broader reviews of synthetic peptides.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro, written TKPRPGP in one-letter notation. Its structure consists of the immunomodulatory tetrapeptide tuftsin, Thr-Lys-Pro-Arg, extended at the carboxyl terminus by a Pro-Gly-Pro segment. The molecular formula is commonly given as C33H57N11O9, corresponding to a monoisotopic mass near 751.4 Da and an average molecular mass near 751.9 Da. All seven residues are proteinogenic amino acids, and the molecule carries no modified side chains or non-natural linkages.
The compound was designed at the Institute of Molecular Genetics of the Russian Academy of Sciences during the 1980s and 1990s. The stated design goal was to retain the immunomodulatory and central nervous system activity attributed to tuftsin while improving resistance to enzymatic breakdown. Adding a proline-rich tail to the short parent peptide was a deliberate strategy, because proline residues restrict the conformations available to many peptidases. The same laboratory produced Semax, an ACTH fragment analog, and both compounds were developed in parallel as short, enzymatically stabilized peptides intended for intranasal use.
=== Pharmacokinetics === Seltorexant has fast absorption with a time to peak levels of 0.3 to 1.5 hours and has a relatively short duration with an elimination half-life of only 2 to 3 hours. No residual effects of the medication were observed 4 hours after daytime administration. The pharmacokinetics of seltorexant are considered to be ideal for sleep induction. Seltorexant is metabolized by the cytochrome P450 enzyme CYP3A4.
Osborne's ligament, also Osborne's band, Osborne's fascia, Osborne's arcade, arcuate ligament of Osborne, or the cubital tunnel retinaculum, refers to either the connective tissue which spans the humeral and ulnar heads of the flexor carpi ulnaris (FCU) or another distinct tissue located between the olecranon process of the ulna and the medial epicondyle of the humerus. It is named after Geoffrey Vaughan Osborne, a British orthopedic surgeon, who described the eponymous tissue in 1957.
=== Cluster headaches === Preventive therapy with verapamil is believed to work because it has an effect on the circadian rhythm and on CGRPs, as CGRP-release is controlled by voltage-gated calcium channels.
"At night, in our rooms, we can't sleep. We twitch and dance and jig about as though we were doing St Vitus's Dance..." "There's less flesh on our bodies than on a skeleton," Francis said. Francis Pélissier said much later: "Londres was a famous reporter but he didn't know about cycling. We kidded him a bit with our cocaine and our pills. Even so, the Tour de France in 1924 was no picnic." The acceptance of drug-taking in the Tour de France was so complete by 1930, when the race changed to national teams that were to be paid for by the organisers, that the rule book distributed to riders by the organiser, Henri Desgrange, reminded them that drugs were not among items with which they would be provided. The use of Pot Belge by road cyclists in continental Europe exemplifies a cross-over between recreational and performance-enhancing abuse of drugs by sportsman.
Sources: en.wikipedia.org
In Ethiopia and Zambia, elaborate scarification is often done on women at puberty, used to denote a willingness to be a mother. The markings show that she can stand the pain of childbirth, as well as being an indication of her emotional maturity.
== Health effects == The World Health Organization and other clinical associations recommend that reducing the consumption of free sugar (sugar sources added during manufacturing) to less than 10% of total energy needs can help to lower disease risk. This amount of sugar consumption is equivalent to about 50 g (1.8 oz) or 12 teaspoons of added sugar per day. As of 2025, the American Heart Association recommends that free sugar intake should be limited to 6% of total daily energy needs, or 36 g (1.3 oz) (9 teaspoons) for adult males, and 25 g (0.88 oz) (6 teaspoons) for women. In many countries, the source and amount of added sugars can be viewed among ingredients on the labels of packaged foods. Added sugars provide no nutritional benefit, but are a source of excess calories that can lead to overweight and increased disease risk.
Nike, Inc announces it will sell "limited quantities" of a replica goalkeeper shirt worn by England goalkeeper Mary Earps during the 2023 Women's World Cup after around 150,000 people signed an online petition calling for them to be made available. A police officer is taken to hospital with critical injuries after being hit by a train while trying to help a distressed man on the railway track in Nottinghamshire. 25 August – Hartwig Fischer announces he will step down as director of the British Museum after treasures were stolen from the London institution. 26 August – Two people are killed after driving a car into a flooded road in the Mossley Hill area of Liverpool. 27 August – The Metropolitan Police launch an investigation into a possible data breach involving details about thousands of their officers after "unauthorised access" was gained to the system of one of its suppliers. 29 August – Nottinghamshire Police officer Sgt Graham Saville, 46, who was struck by a train while trying to help a distressed man on the railway track, dies in hospital from injuries sustained in the incident. London's Ultra Low Emission Zone is expanded to include the whole of Greater London. 30 August – England's Autumn 2023 flu vaccination and COVID-19 booster programme is brought forward by a month, from October to September, as scientists from the UK Health Security Agency monitor the BA.2.86 variant. Although it is not a variant of concern, it is being monitored due to its high number of mutations.
Sources: en.wikipedia.org
The peptidoglycan layer within the bacterial cell wall is a crystal lattice structure formed from linear chains of two alternating amino sugars, namely N-acetylglucosamine (GlcNAc or NAG) and N-acetylmuramic acid (MurNAc or NAM). The alternating sugars are connected by a β-(1,4)-glycosidic bond. Each MurNAc is attached to a short (4- to 5-residue) amino acid chain, containing L-alanine, D-glutamic acid, meso-diaminopimelic acid, and D-alanine in the case of Escherichia coli (a gram-negative bacterium); or L-alanine, D-glutamine, L-lysine, and D-alanine with a 5-glycine interbridge between tetrapeptides in the case of Staphylococcus aureus (a gram-positive bacterium). Peptidoglycan is one of the most important sources of D-amino acids in nature. By enclosing the inner membrane, the peptidoglycan layer protects the cell from lysis caused by the turgor pressure of the cell. When the cell wall grows, it retains its shape throughout its life, so a rod shape will remain a rod shape, and a spherical shape will remain a spherical shape for life. This happens because the freshly added septal material of synthesis transforms into a hemispherical wall for the offspring cells. Cross-linking between amino acids in different linear amino sugar chains occurs with the help of the enzyme DD-transpeptidase and results in a 3-dimensional structure that is strong and rigid. The specific amino acid sequence and molecular structure vary with the bacterial species. The different peptidoglycan types of bacterial cell walls and their taxonomic implications have been described.
A micro-computed tomography (Micro CT) scan of the bone done by Fiona Brock at Cranfield University helped to reveal that the specimen had acid etching and pitting on its surface indicating it may have passed through the digestion system of an animal, likely a hyena. Direct radiocarbon dating estimated the specimen to be more than 50,000 years old, and the sequencing of its mitochondrial DNA (mtDNA) at the Max Planck Institute for Evolutionary Anthropology, showed that Denisova 11 had a sequence consistent with a Neanderthal origin. Further work by scientists at the Max Planck Institute for Evolutionary Anthropology, where previous samples of Denisovan DNA had been sequenced and analyzed uncovered further key evidence relating the specimen Viviane Slon, Svante Pääbo, and others, uncovered Denny's mixed ancestry by confirming that her mitochondrial DNA, inherited from her mother, came from Neanderthal ancestry and finding that the portion of her nuclear DNA inherited from her father was Denisovan. The publication of their results in 2018 provided the first direct evidence of archaic human interbreeding. It has been called a "landmark find" that is reshaping our understanding of how hominins interacted and could help rewrite the story of archaic and modern humans. According to population geneticist Pontus Skoglund from Harvard Medical School, currently at the Francis Crick Institute in London, "To find a first-generation person of mixed ancestry from [Neanderthal and Denisovan groups] is absolutely extraordinary. ...
=== Legal status === In the United States, benzodiazepines are Schedule IV drugs under the Federal Controlled Substances Act, even when not on the market (for example, flunitrazepam), with the exception of flualprazolam, etizolam, clonazolam, flubromazolam, and diclazepam which are placed in Schedule I. In Canada, possession of benzodiazepines is legal for personal use. All benzodiazepines are categorized as Schedule IV substances under the Controlled Drugs and Substances Act. In the United Kingdom, benzodiazepines are Class C controlled drugs, carrying the maximum penalty of 7 years imprisonment, an unlimited fine, or both for possession and a maximum penalty of 14 years imprisonment, an unlimited fine, or both for supplying benzodiazepines to others. In the Netherlands, since October 1993, benzodiazepines, including formulations containing less than 20 mg of temazepam, are all placed on List 2 of the Opium Law. A prescription is needed for possession of all benzodiazepines. Temazepam formulations containing 20 mg or greater of the drug are placed on List 1, thus requiring doctors to write prescriptions in the List 1 format. In East Asia and Southeast Asia, temazepam and nimetazepam are often heavily controlled and restricted. In certain countries, triazolam, flunitrazepam, flutoprazepam and midazolam are also restricted or controlled to certain degrees. In Hong Kong, all benzodiazepines are regulated under Schedule 1 of Hong Kong's Chapter 134 Dangerous Drugs Ordinance. Previously only brotizolam, flunitrazepam and triazolam were classed as dangerous drugs.
Sources: en.wikipedia.org
The sequence is Thr-Lys-Pro-Arg-Pro-Gly-Pro, commonly written as TKPRPGP. It shares the first four residues with tuftsin and carries three prolines in the chain. The proline-rich tail is the main structural feature that separates it from the parent tetrapeptide.
Selank is a synthetic analogue built on the tuftsin tetrapeptide Thr-Lys-Pro-Arg. Extra proline residues were added to the C-terminus during design work. That modification is intended to make the peptide less vulnerable to rapid enzymatic degradation.
Transliteration from Russian produces variant spellings such as Selanc. Many suppliers avoid the trade-style name entirely and list the peptide sequence. Comparing sequences rather than names is the reliable way to confirm two entries describe the same molecule.
Selank is a seven-amino-acid peptide built from the tuftsin sequence plus a Pro-Gly-Pro tail. It is produced by chemical synthesis rather than extracted from a natural source. The free peptide is usually supplied as a lyophilised powder or in an aqueous formulation.