A practical reference on Selank: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
This page was last updated on 2026-07-17 and is reviewed periodically as new material appears.
Regulatory status differs sharply by region. Selank holds a Russian marketing authorization, where it is supplied mainly as nasal drops, while authorities elsewhere have not approved it for medical use. Material sold internationally is therefore usually labeled as a research chemical rather than a medicine. Peer-reviewed publications come predominantly from Russian laboratories, and sample sizes are generally small. Whether the compound produces comparable effects under independent, well-controlled replication remains an open question that the broader literature has not settled.
Selank is a synthetic heptapeptide developed in Russia as a structural analogue of tuftsin, a naturally occurring immunomodulatory tetrapeptide. Its sequence, Thr-Lys-Pro-Arg-Pro-Gly-Pro, keeps the tuftsin core at the N-terminus and appends a Pro-Gly-Pro tail. Researchers at the Institute of Molecular Genetics in Moscow synthesized the compound during the 1990s while searching for peptides with combined anxiolytic and immunomodulatory activity. The added tail was intended to resist enzymatic cleavage and prolong the molecule's presence in circulation.
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 | Analog of the tetrapeptide tuftsin |
| Sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Reported consistently across pharmacopoeial descriptions |
| Appearance | White to off-white lyophilized powder | Typical form of research-grade material |
| Solubility | Freely soluble in water | Aqueous buffers; poor in nonpolar solvents |
| Typical storage temperature | -20 degrees Celsius | Lyophilized powder; protect from moisture |
Outside its country of origin the compound is generally handled as a research chemical rather than an approved medicine. No regulatory approval from the United States Food and Drug Administration or the European Medicines Agency has been granted for human use. Identity and purity are normally checked by reverse-phase high-performance liquid chromatography, with mass spectrometry used to confirm the molecular mass. Lyophilised material is stored cold and desiccated, and repeated freeze-thaw cycles are avoided.
Published work on this peptide almost always uses intranasal delivery, with drops or a spray applied to the nasal mucosa. Some animal experiments have used subcutaneous or intraperitoneal injection, and a smaller number have compared routes directly. Oral administration is not a focus of the literature, because short peptides of this size are broken down by digestive enzymes and cross intestinal barriers poorly. How much of an intranasal dose reaches the bloodstream intact in humans remains an open question.
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.
Measuring peptide exposure inside the brain is technically difficult. Selank is degraded rapidly in plasma, and assays must separate intact peptide from fragments, which favors targeted mass spectrometry over immunoassays alone. Reported half-lives are short, on the order of minutes, so effects observed hours later are attributed to downstream signaling rather than to the parent compound. Blood-brain barrier permeability is debated and rarely quantified directly. Gaps include absent dose-response characterization, inconsistent reporting of purity, and almost no pharmacokinetic data from human participants.
Proposed mechanisms centre on the GABAergic system. Animal and tissue studies report changes in GABA-A receptor expression and reduced activity of GABA transaminase, the enzyme that degrades GABA. Effects on monoamine turnover, including serotonin and dopamine pathways, are also described, and a separate line of work links the peptide to increased expression of brain-derived neurotrophic factor in hippocampal tissue. Most of these findings come from rodent models and cell preparations. How the individual observations combine into a single coherent mode of action is not settled.
Pharmacokinetic data are sparse and largely derived from animal work. After intranasal administration the peptide appears in plasma within minutes, and reported half-lives are short, on the order of minutes to tens of minutes. Degradation proceeds through ordinary proteolytic cleavage into constituent amino acids and smaller fragments. Direct evidence that intact Selank reaches brain tissue in meaningful amounts is limited, and the extent of blood-brain barrier penetration is debated. Some authors argue that fragments, not the parent peptide, carry much of the observed activity.
== Variants == Chocolate agar with the addition of bacitracin becomes selective for the genus Haemophilus. Another variant of chocolate agar called Thayer–Martin agar contains an assortment of antibiotics that select for Neisseria species.
Chest trauma leading to aortic dissection can be divided into two groups based on cause: blunt chest trauma (commonly seen in car accidents) and iatrogenic. Iatrogenic causes include trauma during cardiac catheterization or due to an intra-aortic balloon pump. Aortic dissection may be a late sequela of heart surgery. About 18% of individuals who present with an acute aortic dissection have a history of open-heart surgery. Individuals who have undergone aortic valve replacement for aortic insufficiency are at particularly high risk because aortic regurgitation causes increased blood flow in the ascending aorta. This can cause dilatation and weakening of the walls of the ascending aorta. In December 2018, the U.S. Food and Drug Administration (FDA) issued a warning that fluoroquinolones may increase the risk of aortic aneurysm and aortic dissection, particularly in older adults and in patients with hypertension, Marfan syndrome, Ehlers-Danlos syndrome, atherosclerosis, peripheral vascular disease, or a history of aneurysms. Syphilis only potentially causes aortic dissection in its tertiary stage.
L-Arginine:glycine amidinotransferase (AGAT; EC 2.1.4.1) is the enzyme that catalyses the transfer of an amidino group from L-arginine to glycine. The products are L-ornithine and glycocyamine, also known as guanidinoacetate, the immediate precursor of creatine. Creatine and its phosphorylated form play a central role in the energy metabolism of muscle and nerve tissues. Creatine is in highest concentrations in the skeletal muscle, heart, spermatozoa and photoreceptor cells. Creatine helps buffer the rapid changes in ADP/ATP ratio in muscle and nerve cells during active periods. Creatine is also synthesized in other tissues, such as pancreas, kidneys, and liver, where amidinotransferase is located in the cytoplasm, including the intermembrane space of the mitochondria, of the cells that make up those tissues.
=== Natural Killer T-cells === Natural killer T-cells (NKT cells) can also be visualized with tetramer technology. NKT cells bind to proteins that present lipid or glycolipid antigens. The antigen presenting complex that NKT cells bind to involves CD1 proteins, so tetramers made of CD1 can be used to stain for NKT cells.
Sources: en.wikipedia.org
The Parliamentary Commissioner for Standards launches an investigation into Democratic Unionist Party MP Sammy Wilson for an alleged breach of lobbying rules after he failed to declare an interest when tabling a question on the Turkish Republic of Northern Cyprus, and following a visit to the area. 16 November – The SNP's National Executive Committee proposes cutting the number of staff at its headquarters from 26 to 16. Ruth Maguire, MSP for Cunninghame South, announces she will not seek re-election at the 2026 Scottish Parliament election because she is to undergo treatment for cancer. Protesters gather outside Welsh Labour's party conference to oppose changes to inheritance tax for farmers outlined in the October budget as Prime Minister Sir Keir Starmer defends the government's changes. 17 November – Sir Ed Davey, the leader of the Liberal Democrats, says that Jane Dodds, who leads the party in Wales, should reflect on her position after a report found she made a "grave error of judgement" in her handling of a sexual abuse scandal when she worked for the Church of England. 18 November – At the 2024 G20 Rio de Janeiro summit, Starmer holds talks with Chinese president Xi Jimping and emphasises the importance of a "strong UK–China relationship" for both countries. 19 November – Scottish Labour leader Anas Sarwar says his party will expand the eligibility for winter fuel payments in Scotland if they win the 2026 Scottish Parliament election.
== Characteristics == 210Po is an alpha emitter that has a half-life of 138.4 days; it decays directly to its stable daughter isotope, 206Pb. A milligram (5 curies) of 210Po emits about as many alpha particles per second as 5 grams of 226Ra, which means it is 5,000 times more radioactive than radium. A few curies (1 curie equals 37 gigabecquerels, 1 Ci = 37 GBq) of 210Po emit a blue glow which is caused by ionisation of the surrounding air. About one in 100,000 alpha emissions causes an excitation in the nucleus which then results in the emission of a gamma ray with a maximum energy of 803 keV.
General Cao, L. (2014). Behavior Informatics: A New Perspective. IEEE Intelligent Systems (Trends and Controversies), 29(4): 62–80. Clemons, E. K. (2008). "How Information Changes Consumer Behavior and How Consumer Behavior Determines Corporate Strategy". Journal of Management Information Systems. 25 (2): 13–40. doi:10.2753/mis0742-1222250202. S2CID 16370526. Dowhan, D (2013). "Hitting Your Target". Marketing Insights. 35 (2): 32–38. Perner, L. (2008), Consumer behavior. University of Southern California, Marshall School of Business. Retrieved from http://www.consumerpsychologist.com/intro_Consumer_Behavior.html Szwacka-Mokrzycka, J (2015). "TRENDS IN CONSUMER behavior CHANGES. OVERVIEW OF CONCEPTS". Acta Scientiarum Polonorum. Oeconomia. 14 (3): 149–156.
Psylocke has been adapted in various forms of media, including films, television series, and video games. Olivia Munn portrayed the character in the film X-Men: Apocalypse. She appears in X-Men '97 season 2, voiced by Naoko Mori. The Sai incarnation of Psylocke from Demon Days: X-Men appears as a playable character in the video game Marvel Rivals, voiced by Alpha Takahashi in the English version.
Chloroform began to replace ether as an anesthetic in the United States at the beginning of the 20th century. It was soon abandoned in favor of ether when its hepatic and cardiac toxicity, especially its tendency to cause potentially fatal cardiac dysrhythmias, became apparent. In fact, the use of chloroform versus ether as the primary anesthetic gas varied by country and region. For instance, Britain and the American South stuck with chloroform while the American North returned to ether. John Snow quickly became the most experienced British physician working with the new anesthetic gases of ether and chloroform thus becoming, in effect, the first British anesthetist. Through his careful clinical records he was eventually able to convince the elite of London medicine that anesthesia (chloroform) had a rightful place in childbirth. Thus, in 1853 Queen Victoria's accoucheurs invited John Snow to anesthetize the Queen for the birth of her eighth child. From the beginnings of ether and chloroform anesthesia until well into the 20th century, the standard method of administration was the drop mask. A mask was placed over the patient's mouth with some fabric in it and the volatile liquid was dropped onto the mask with the patient spontaneously breathing. Later development of safe endotracheal tubes changed this.
Sources: en.wikipedia.org
Selank is a synthetic seven-amino-acid peptide modeled on tuftsin, a fragment of the immunoglobulin G heavy chain. It was designed in Russia to combine anxiolytic and immunomodulatory properties in one molecule.
The first four residues of Selank reproduce the tuftsin sequence Thr-Lys-Pro-Arg. A Pro-Gly-Pro extension at the C-terminus was added to slow enzymatic breakdown and extend residence time.
It holds marketing authorization in Russia, where nasal drop formulations are sold. No equivalent approval exists in the European Union, the United States, or most other countries.
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.