Heptapeptide 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.
Last reviewed on 2025-09-18. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
| 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.
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.
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.
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.
== Pharmacokinetics == Most wrinkle fillers are temporary because they are eventually metabolized by the body. Some people may need more than one injection to achieve the wrinkle-smoothing effect. The effect lasts for about six months. Results depend on health of the skin, skill of the health care provider, and the type of filler used. Regardless of material (whether synthetic or organic) filler duration is highly dependent on amount of activity in the body area where it is injected. Exercise and high intensity activities such as manual labor can stimulate blood flow and shorten the lifespan of fillers.
=== Pharmacodynamics === Gabapentin is a ligand of the α2δ calcium channel subunit. The α2δ-1 protein is coded by the CACNA2D1 gene. α2δ was first described as an auxiliary protein connected to the main α1 subunit (the channel-forming protein) of high voltage activated voltage-dependent calcium channels (L-type, N-type, P/Q type, and R-type). The same α2δ protein has more recently been shown to interact directly with some NMDA-type and AMPA-type glutamate receptors at presynaptic sites and also with thrombospondin (an extracellular matrix protein secreted by astroglial cells). Gabapentin is not a direct calcium channel blocker: it exerts its actions by disrupting the regulatory function of α2δ and its interactions with other proteins. Gabapentin reduces delivery of intracellular calcium channels to the cell membrane, reduces the activation of the channels by the α2δ subunit, decreases signaling to lead to neurotransmitters release, and disrupts interactions of α2δ with voltage gated calcium channels but also with NMDA receptors, neurexins, and thrombospondin. These proteins are found as mutually interacting parts of the presynaptic active zone, where numerous protein molecules interact with each other to enable and to regulate the release of neurotransmitters from presynaptic vesicles into the synaptic space. Out of the four known isoforms of α2δ protein, gabapentin binds with similar high affinity to two: α2δ-1 and α2δ-2. All of the pharmacological properties of gabapentin tested to date are explained by its binding to just one isoform – α2δ-1.
== Chemistry and mechanism of action == Teduglutide differs from natural GLP-2 by a single amino acid: an alanine is replaced with a glycine. This blocks breaking down of the molecule by dipeptidyl peptidase and increases its half-life from seven minutes (GLP-2) to about two hours, while retaining its biological actions. These include maintenance of the intestinal mucosa, increasing intestinal blood flow, reducing gastrointestinal motility and secretion of gastric acid.
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Paroxetine is a constrained structural analogue of fluoxetine where the linear phenylpropylamine group of fluoxetine has been folded into a piperidine ring (figure 5). The compound has the possibility of four stereoisomers because it contains two chiral centers, but one of them, the (3S,4R)-isomer, is marketed as paroxetine. Research has shown that stereochemical factors affect affinity of the molecule for SERT where substitution into the 2-ortho-position of either aromatic rings decreases affinity for rat SERT by as much as 10–100 times, where the greatest loss occurs in the phenoxy ring. Paroxetine is the most potent SSRI drug available, but it is less selective for SERT than fluvoxamine and sertraline. Paroxetine also has weak NET inhibition which could contribute to its efficacy in depression, especially at higher doses. As demonstrated in table 2, paroxetine also inhibits the NOSs enzyme which could be the reason for its sexual dysfunction adverse effect, especially in men. Paroxetine shows the highest affinity for muscarinic receptors of all the SSRIs which results in weak anticholinergic activity and therefore undesirable adverse effects.
Some countries used accelerated dose 1 plans with extended dose 2 intervals after the first dose in order to extend vaccination to as many people as possible until vaccine availability improved. Data suggests that people who have recovered from COVID-19 may only require a single dose of an mRNA vaccine to reach full two dose immunity.
=== Evolution of mental illness representation in film === An overused trope used in film and television is depicting villains or murderers as mentally ill. This trope has evolved throughout the history of filmmaking and cinema. First introduced in the early 1900s, films like Dr. Mabuse, the Gambler (1922) and The Black Cat (1934) depicted the mentally ill villains as mad, evil doctors. Then, with the rise of Alfred Hitchcock films, he introduced the serial killer in Psycho (1960), whose character trope was subsequently used in films like Homicidal (1961), Maniac (1963), Paranoiac (1963), and Nightmare (1963). The 1970s and 1980s brought the popular "slasher" film genre, introducing iconic horror characters such as Michael Myers, Jason, and Freddy Kruger from the franchises Halloween, Friday the 13th, and A Nightmare on Elm Street, respectively.
Sources: en.wikipedia.org
in military personnel exposed to high radiation, (during accidents at nuclear reactors), or to combat the action of toxic substances (including organophosphate compounds), combat traumas, as well as to prevent acute respiratory infections and flu. They were also used to treat laser retinal lesions in experimental animals exposed to a combat laser. All other peptide preparations, (natural and synthetic) are at different stages of studying in patients with different diseases. Among the important advantages of all designed peptide preparations is that they lack any toxic, allergic or adverse effects, this has been proven both in experimental and clinical studies. The main objective of studies for the recent decade was fundamental research devoted to the role that small peptides play in the evolution and development of living matter. It was crucial for understanding the mechanism of the action of peptides and evidencing their safety and effectiveness, whilst designing new medicinal preparations, dietary supplements, cosmetics and veterinary preparations.
=== Consumable-free thermal modulation === This approach eliminates the need for liquid nitrogen for thermal modulation. The system employs a closed cycle refrigerator/heat exchanger to produce −90 °C at the jet. The cooling is done by indirect cooling of gaseous nitrogen (or air) and therefore is capable of modulating volatile and semi volatile compounds over the C7+ range.
=== Conformational change in non-inhibitory functions === Certain non-inhibitory serpins also use the serpin conformational change as part of their function. For example, the native (S) form of thyroxine-binding globulin has high affinity for thyroxine, whereas the cleaved (R) form has low affinity. Similarly, transcortin has higher affinity for cortisol when in its native (S) state, than its cleaved (R) state. Thus, in these serpins, RCL cleavage and the S to R transition has been commandeered to allow for ligand release, rather than protease inhibition. In some serpins, the S to R transition can activate cell signalling events. In these cases, a serpin that has formed a complex with its target protease, is then recognised by a receptor. The binding event then leads to downstream signalling by the receptor. The S to R transition is therefore used to alert cells to the presence of protease activity. This differs from the usual mechanism whereby serpins affect signalling simply by inhibiting proteases involved in a signalling cascade.
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.