Everything below concerns Selank. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Last reviewed on 2026-07-09. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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, 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.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic heptapeptide | Modeled on tuftsin |
| Amino acid sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Seven residues |
| Approximate molecular mass | Around 750 Da | Depends on counter-ion and hydration |
| Common forms | Lyophilized powder | Also described as aqueous solution |
| Primary origin of research | Russian laboratories | Mid-1990s onward |
Proposed mechanisms center on modulation of the GABA system, but no single molecular target has been confirmed. Rodent studies report changes in GABA-A receptor expression and in the turnover of serotonin, dopamine, and norepinephrine in several brain regions. Increases in brain-derived neurotrophic factor and its receptor have also been described after repeated administration. These findings come largely from animal models, and the degree to which they describe human neurochemistry remains an open question. The mechanism is best characterized as multi-system and not fully resolved.
Pharmacokinetic data are limited. Like most short peptides, Selank is vulnerable to plasma and tissue peptidases, and its measured half-life in circulation is short, on a minutes scale. The Pro-Gly-Pro tail slows this degradation but does not eliminate it. Intranasal administration is the route described in most reports, with absorption through the nasal mucosa and a hypothesized path into the central nervous system that avoids the blood-brain barrier. Direct measurements of human brain exposure are unavailable, so distribution claims rest on inference from animal work.
Clinical evidence comes mainly from small studies conducted in Russia, several of which were open-label or lacked robust blinding. Reported outcomes include lower anxiety scores, changes in attention measures, and effects on asthenic states following illness. Sample sizes are typically in the tens of participants, and independent replication outside the region is scarce. Reviews published in English generally note the limited methodological quality of the underlying trials. Whether the compound produces clinically meaningful effects under rigorous conditions remains unresolved.
Purity assessment relies mainly on reverse-phase high-performance liquid chromatography with ultraviolet detection. Because the peptide lacks a strong chromophore, detection often uses backbone absorbance near 214 nm. Identity is confirmed by mass spectrometry, typically electrospray ionization or matrix-assisted laser desorption, comparing the measured mass against the expected value. Amino acid analysis can verify composition after acid hydrolysis. Diastereomer content and residual counterions are reported less often, although both can influence biological assays.
Lyophilized material is generally stable for extended periods when kept dry at or below minus twenty degrees Celsius. Working solutions are less stable, and common practice is to aliquot and freeze them so that repeated freeze-thaw cycles are avoided. Aqueous solutions are sensitive to pH extremes and to microbial growth, so short-term storage at refrigerator temperature is typical. Oxidation and hydrolysis are the principal degradation routes. Reconstitution with sterile water or a mild buffer is standard, and solutions should be protected from light.
Regulatory treatment varies by jurisdiction. In Russia the compound is a registered prescription product, while in the European Union and the United States it is generally handled as a research chemical without a marketing authorization. Suppliers therefore operate outside pharmaceutical oversight, and buyers rely on supplier documentation for purity and identity claims. Chain of custody and third-party testing are the main verification tools. Analysts note that the absence of a pharmacopoeial monograph for research-grade material limits standardization across vendors.
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.
The compound has a calculated molecular weight near 751.9 daltons and carries a net positive charge at physiological pH because of its arginine residue. It dissolves freely in water and in common aqueous buffers, and typically appears as a white or off-white lyophilized powder. The amide backbone makes the molecule susceptible to peptidases, which limits oral use and favors intranasal or parenteral routes. Nomenclature in the literature varies: the substance is also described by the sequence abbreviation TP-7 and by a Russian trade designation.
The primary structure of Selank is Thr-Lys-Pro-Arg-Pro-Gly-Pro, corresponding to the molecular formula C33H57N11O9 and a monoisotopic mass of roughly 751.9 daltons. The N-terminal threonine and the arginine residue in the fourth position are shared with tuftsin, which carries the sequence Thr-Lys-Pro-Arg. The three additional residues at the C-terminus, Pro-Gly-Pro, extend the chain and are associated with greater resistance to enzymatic degradation. This extension also separates Selank from the shorter parent peptide.
Naming conventions place Selank in the same research family as Semax, another Russian-developed peptide investigated for cognitive effects. The two compounds share a lineage but differ in sequence and in the biological systems proposed as their targets. Semax descends from ACTH fragments, whereas Selank descends from tuftsin. Publications sometimes identify Selank by its full peptide sequence or by laboratory codes rather than one uniform trade name. Because replication outside Russia is limited, reports on its properties are best read alongside the study design and the purity of the material tested.
Muscle cells (myocytes) form the active contractile tissue of the body. Muscle tissue functions to produce force and causes locomotion, movement within internal organs, and other types of motion. Muscle is formed of contractile filaments and is separated into three main types; smooth muscle, skeletal muscle and cardiac muscle. Smooth muscle has no striations when examined microscopically. It contracts slowly but maintains contractibility over a wide range of stretch lengths. It is found in such organs as sea anemone tentacles and the body wall of sea cucumbers. Skeletal muscle contracts rapidly but has a limited range of extension. It is found in the movement of appendages and jaws. Obliquely striated muscle is intermediate between the other two. The filaments are staggered and this is the type of muscle found in earthworms that can extend slowly or make rapid contractions. In higher animals striated muscles occur in bundles attached to bone to provide movement and are often arranged in antagonistic sets. Smooth muscle is found in the walls of the uterus, bladder, intestines, stomach, oesophagus, respiratory airways, and blood vessels. Cardiac muscle is found only in the heart, allowing it to contract and pump blood through the body.
==== Modulation of mitochondrial activity ==== Cannabinoids influence mitochondrial processes, including calcium regulation, apoptosis, electron transport chain activity, mitochondrial respiration and ATP production. Mitochondrial dynamics—encompassing the processes of fusion and fission, as well as alterations in morphology and organelle mobility, are also affected by cannabinoid exposure. In addition, cannabinoids have been shown to modulate mitochondrial biogenesis through the dysregulation of PGC-1α levels. These effects are complex, involving direct membrane interactions and receptor-mediated pathways, but a unified hypothesis is lacking due to conflicting data.
=== Primary structure === EosFP consists of 226 amino acids. It has a molecular mass of 25.8 kDa and its pI is 6.9. Eos has 84% identical residues to Kaede, a fluorescent protein that originated in a different scleractinian coral Trachyphyllia geoffroyi, but can also be irreversibly converted from a green to red emitting form using UV light. Excluding residues Phe-61 and His-62, the chromophore environment and chromophore itself are unaffected by photochemical modification. Wild-type EosFP has a tetrameric arrangement of subunits where each subunit has the same β-can structure as GFP. This structure includes an 11-stranded barrel and, down the central axis, the fluorophore-containing helix.
== Function == In most fish species, barbels are used to aid in the acquisition of food in bodies of water that have low visibility due to low light conditions or murky waters. The taste receptors are able to detect enzymes in the water and help the fish identify if it is from a possible food source or possible sources of danger. The abyssal zone scavengers Coryphaenoides armatus possess one small mandible barbel that they use to search the seafloor for carrion to eat. Freckled Goatfish, Upeneus tragula, develop barbels as a response to food availability. When starved of food for two days under laboratory conditions, U. tragula develop large barbels compared to those developed by those who were fed consistently. The large barbels help the organism capture prey and compete against other individuals. However, individuals that developed large barbels also experienced a decreased growth rate. In the species Triportheus signatus, individuals have been found to develop barbels late in life as a response to low dissolved oxygen in pools left after flood waters recede following the rainy season. These structures are more vascularized than barbels of other fish species to help gas exchange in low oxygen conditions and direct more water flow over the gills.
Sources: en.wikipedia.org
Supplementation can also contribute to the managing the symptomatic effects of hyperandrogenism. In a meta-analysis, high-dose vitamin D supplements given to women with vitamin D deficiency due to PMOS improved glucose levels, insulin sensitivity, and cholesterol levels, as well as lowering testosterone, sex hormone-binding globulin, and the free androgen index, all of which are associated with hyperandrogenism. Vitamin D supplementation in women with vitamin D deficiency but without PMOS did not show the same results.
=== Cabinet committees === On 21 March the cabinet division would issue two separate notifications constituting the Economic Coordination Committee (ECC) and the Cabinet Committee on Energy (CCoE), by the Prime Minister under terms of rule 17(2) of Rules of Business, 1973. Both would be retained directly under Shehbaz Sharif, becoming Chairman of both committees. On the same day Shehbaz would also approve the reconstitution of the Cabinet Committee on Privatization (CCoP), with MoFA Ishaq Dar as Chairman with the secretarial support of the Committee provided by the Aviation Division; and the reconstitution of the Cabinet Committee on State-Owned Enterprises (CCoSOEs), with Minister of Finance and Revenue, Muhammad Aurangzeb as Chairman. Additional Committees constituted on 21 March include the Cabinet Committee on Disposal of Legislative Cases (CCLC) under Azam Nazeer Tarar, the Cabinet Committee on Chinese Investment Projects (CCoCIP) under Ahsan Iqbal, and a committee to "speed up" the privatization of Pakistan International Airways (PIA) under Khawaja Asif. With forty-eight hours, on 23 March the Cabinet Division issued a notification, appointing Muhammad Aurangzeb as new Chairman of the ECC, with Shehbaz Sharif withdrawing from the committee Previously Aurangzeb held chairmanship of only the Cabinet Committee on SOEs (CCoSOEs), while Ishaq Dar also held a prominent role in the new cabinet committees as chairman of Cabinet Committee on Privatisation (CCoP). This was a departure from past practices, where finance ministers chaired three out of four committees.
=== Approximation of the reactant === During enzyme catalytic reaction, the substrate and active site are brought together in a close proximity. This approach has various purposes. Firstly, when substrates bind within the active site the effective concentration of it significantly increases than in solution. This means the number of substrate molecules involved in the reaction is also increased. This process also reduces the desolvation energy required for the reaction to occur. In solution substrate molecules are surrounded by solvent molecules and energy is required for enzyme molecules to replace them and contact with the substrate. Since bulk molecules can be excluded from the active site this energy output can be minimised. Next, the active site is designed to reorient the substrate to reduce the activation energy for the reaction to occur. The alignment of the substrate, after binding, is locked in a high energy state and can proceed to the next step. In addition, this binding is favoured by entropy as the energy cost associated with solution reaction is largely eliminated since solvent cannot enter active site. In the end, the active site may manipulate the Molecular orbital of the substrate into a suitable orientation to reduce activation energy. The electrostatic states of substrate and active site must be complementary to each other. A polarized negatively charged amino acid side chain will repel uncharged substrate. But if the transition state involves the formation of an ion centre then the side chain will now produce a favourable interaction.
Sources: en.wikipedia.org
These procedures aim to inject bio-compatible material (perianal injectable bulking agents, also termed sphincter bulking agents or biomaterial injectables) into the walls of the anal canal, in order to bulk out these tissues. This may bring the walls of the anal canal into tighter contact, raising the resting pressure, creating more of a barrier to the loss of stool, and thereby reducing fecal incontinence. This procedure has many advantages over more invasive surgery, since there are rarely any serious complications.
In 2024, Andrea Cau published a study on the phylogenetics of compsognathids that called the assessment of these taxa into question. The paper recovered Sinosauropteryx, along with three other proposed compsognathids in a polytomy within basal Coelurosauria. This polytomy notably did not include Composognathus proper, which would make none of these species compsognathids. In their description of S. lingyuanensis, Qiu et al. (2025) also commented on the monophyly of Compsognathidae and revived the previously monotypic Sinosauropterygidae within Coelurosauria as a monophyletic family containing all compsognathid-like theropods from the Jehol Biota of China (Sinosauropteryx, Huadanosaurus, Huaxiagnathus and Sinocalliopteryx) in addition to Mirischia. Their phylogenetic analyses using two separate datasets are reproduced below:
It is then treated with high-pressure elution from cation exchange resins, and the berkelium phase is oxidized and extracted using one of the procedures described above. Reduction of the thus-obtained berkelium(IV) to the +3 oxidation state yields a solution, which is nearly free from other actinides (but contains cerium). Berkelium and cerium are then separated with another round of ion-exchange treatment.
Sources: en.wikipedia.org
Selank is a synthetic peptide made of seven amino acids. It is modeled on tuftsin, a natural tetrapeptide, with an added three-residue tail. It is not a small-molecule drug.
It originates from research in Russia, associated with the Institute of Molecular Genetics of the Russian Academy of Sciences. The first descriptions date to the mid-1990s. Most published studies come from Russian laboratories.
No, Selank itself does not occur naturally. Its backbone is based on tuftsin, which is produced in the body, but the seven-residue version is a synthetic construct. It is supplied as a manufactured peptide.
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.