The short version of tuftsin fits in a sentence. The long version — which is the one that helps — is below.
This page was last updated on 2025-11-18 and is reviewed periodically as new material appears.
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.
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.
Reported pharmacological effects center on reduced anxiety-like behavior in animal models and on measures of memory and learning. Proposed contributing mechanisms include modulation of GABAergic signaling, shifts in monoamine turnover, and changes in the activity of enzymes that degrade neuropeptides. Effects on the expression of genes linked to neuroplasticity have also been described. No single molecular target is widely accepted, and whether the behavioral findings arise from one pathway or several remains an open question.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic heptapeptide | Tuftsin analogue with a C-terminal Pro-Gly-Pro tail |
| Amino acid sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Abbreviated TKPRPGP in most catalogues |
| Molecular mass | About 752 Da | Value for the free peptide |
| Solubility | Freely soluble in water | Aqueous solutions are kept cold and used promptly |
| Typical storage | -20 °C, dry, protected from light | Applies to the lyophilised powder before reconstitution |
Selank is a synthetic heptapeptide developed in Russia during the 1990s. Researchers at the Institute of Molecular Genetics of the Russian Academy of Sciences designed it as a stabilized analog of tuftsin, a naturally occurring immunomodulatory tetrapeptide. The compound has been studied primarily for its reported anxiolytic and nootropic effects. It remains largely unknown in Western pharmacology and is not approved as a medicine by major regulators such as the FDA or the EMA.
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.
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.
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.
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.
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.
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.
They suggest the toxicity is due to three constituents that work in combination to produce encephalopathy, Pleurocybelline a heat stable and high molecular weight glycoprotein, Pleurocybella porrigens lectin a purified lectin, and Pleurocybellaziridine an amino acid derivative. Experimental studies in rodents showed that the Pleurocybelline and Pleurocybella porrignes lectin form a complex exhibiting non-specific proteolytic activity that disrupts the blood-brain barrier. Injection of this combination into mice resulted in degradation of protein substrates and the disappearance of the marker GLUT1 which indicates disruption of the blood-brain barrier. This activity is proposed to arise from the functional interaction of the two proteins, where their combination gains proteolytic properties not present in either protein alone. This leads to broad degradation of extracellular and membrane associated proteins required for blood-brain barrier disruption. Although neither protein alone is directly neurotoxic, this disruption is proposed to enable Pleurocybellaziridine to enter brain cells. Pleurocybellaziridine was found after the comparison of related amino acid derivatives which led researchers to infer the existence of a precursor. Once the blood-brain barrier is compromised Pleurocybellaziridine was able to access neural tissue, where it is thought to exert cytotoxic effects, particularly on oligodendrocytes.
== Reactivity == Like most alkanes, hexanes typically exhibit low reactivity and are suitable solvents for reactive compounds. Commercial samples of n-hexane however often contains methylcyclopentane, which features tertiary C-H bonds, which are incompatible with some radical reactions.
It is also used in the preparation of sour pickles, cabbage, and other dishes. In Romania, dill (mărar) is widely used as an ingredient for soups such as 'borş' (pronounced "borsh"), pickles, and other dishes, especially those based on peas, beans, and cabbage. It is popular for dishes based on potatoes and mushrooms and may be found in many summer salads (especially cucumber salad, cabbage salad and lettuce salad). During springtime, it is used in omelets with spring onions. It often complements sauces based on sour cream or yogurt and is mixed with salted cheese and used as a filling. Another popular dish with dill as a main ingredient is dill sauce, which is served with eggs and fried sausages. In Hungary, dill is very widely used. It is popular as a sauce or filling, and mixed with a type of cottage cheese. Dill is also used for pickling and in salads. The Hungarian name for dill is 'kapor'. In Serbia, dill is known as 'mirodjija' and is used as an addition to soups, potato and cucumber salads, and French fries. It features in the Serbian proverb, "бити мирођија у свакој чорби" /biti mirodjija u svakoj čorbi/ (to be a dill in every soup), which corresponds to the English proverb "to have a finger in every pie". In Greece, dill is known as άνηθος (anithos). In antiquity it was used as an ingredient in wines that were called "anithites oinos" (wine with anithos-dill). In modern days, dill is used in salads, soups, sauces, and fish and vegetable dishes.
Drostanolone propionate is a prodrug of drostanolone. Like other AAS, drostanolone is an agonist of the androgen receptor (AR). It is not a substrate for 5α-reductase and is a poor substrate for 3α-hydroxysteroid dehydrogenase (3α-HSD), and therefore shows a high ratio of anabolic to androgenic activity. As a DHT derivative, drostanolone is not a substrate for aromatase and hence cannot be aromatized into estrogenic metabolites. While no data are available on the progestogenic activity of drostanolone, it is thought to have low or no such activity similarly to other DHT derivatives. Since the drug is not 17α-alkylated, it is not known to cause hepatotoxicity. Drostanolone propionate, via its active form drostanolone, interacts with the AR and activates a cascade of genetic changes, including increased protein synthesis (anabolism) and decreased amino acid degradation (catabolism). It also induces a reduction or inhibition of prolactin or estrogen receptors in the breasts, which is linked to its antitumor effects.
Sources: en.wikipedia.org
==== U.S. regulatory restrictions ==== The US Food and Drug Administration (FDA) position is that red yeast rice products that contain monacolin K are identical to a prescription drug and, thus, subject to regulation as a drug. In 1998, the FDA initiated action to ban a product (Cholestin) containing red yeast rice extract. The U.S. District Court in Utah ruled in favor of allowing the product to be sold without restriction. This decision was reversed on appeal to the U.S. Court of Appeals in 2001. In 2007, the FDA sent warning letters to two dietary supplement companies. One was making a monacolin content claim about its RYR product and the other was not, but the FDA noted that both products contained monacolins. Both products were withdrawn. In a press release the FDA "...is warning consumers to not buy or eat red yeast rice products... may contain an unauthorized drug that could be harmful to health." The rationale for "harmful to health" was that consumers might not understand that the dangers of monacolin-containing red yeast rice are the same as those of prescription statin drugs. A products analysis report from 2010 tested 12 products commercially available in the U.S. and reported that per 600 mg capsule, total monacolins content ranged from 0.31 to 11.15 mg. A 2017 study tested 28 brands of red yeast rice supplements purchased from U.S. retailers, stating "the quantity of monacolin K varied from none to prescription strength". Many of these avoid FDA regulation by not having any appreciable monacolin content.
The water normally used to quench steel will also be in short supply, and require strong agitation. Casting steel can be a difficult process in microgravity, requiring special heating and injection processes, or spin forming. Heating can be performed using sunlight combined with electrical heaters. The casting process would also need to be managed to avoid the formation of voids as the steel cools and shrinks. Various metal-working techniques can be used to shape the metal into the desired form. The standard methods are casting, drawing, forging, machining, rolling, and welding. Both rolling and drawing metals require heating and subsequent cooling. Forging and extrusion can require powered presses, as gravity is not available. Electron beam welding has already been demonstrated on board the Skylab, and will probably be the method of choice in space. Machining operations can require precision tools which will need to be imported from the Earth for some duration. New space manufacturing technologies are being studied at places such as Marshall's National Center for Advanced Manufacturing. The methods being investigated include coatings that can be sprayed on surfaces in space using a combination of heat and kinetic energy, and electron beam free form fabrication of parts. Approaches such as these, as well as examination of material properties that can be investigated in an orbiting laboratory, will be studied on the International Space Station by NASA and Made In Space, Inc.
The party then became subject to the broader shift to the right of the Weimar society in late 1920s caused by the Great Depression and dissatisfaction with the Weimar political system, which also included the Catholic groups. In an updated policy platform in 2022, the Centre Party declares its objective is to protect the "Christian-Jewish roots of Europe and defend the free-democratic basic order of the Basic Law of the Federal Republic of Germany." The party supports a social market economy, keeping national debt low and strong social security systems. The party supports the integration of immigrants residing legally in Germany while protecting German national identity and ensuring compulsory laws for immigrants to learn German, understand German culture and undergo a values test before acquiring citizenship. It also calls for strong law and order and national security policies to combat violent crime and terrorism and supports German membership of NATO.
Sources: en.wikipedia.org
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.
Tuftsin is a natural tetrapeptide derived from the Fc portion of immunoglobulin G. Selank retains that tetrapeptide at its N-terminus and adds three residues to improve resistance to enzymatic breakdown. The relationship is structural, and the two molecules are not interchangeable in experimental work.
It holds a product registration in Russia for intranasal use as an anxiolytic. Registrations of that kind are not automatically accepted by regulators elsewhere. In most other countries it is treated as an unapproved substance or a research material.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro, designed as a metabolically stabilized analogue of the endogenous tetrapeptide tuftsin. It has been studied mainly against anxiety-related and cognitive endpoints rather than as an approved medicine in most jurisdictions.