A practical reference on Tuftsin: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
This page was last updated on 2026-01-24 and is reviewed periodically as new material appears.
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 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.
Solubility behavior is a practical concern for handling. Selank dissolves readily in water and in common aqueous buffers, which simplifies preparation of working solutions. The choice of solvent, ionic strength, and pH can influence aggregation over time, particularly at higher concentrations. Aqueous solutions are typically sterile-filtered before use. Because stability depends on several variables, storage and handling notes should be treated as general guidance rather than fixed rules, and specific values are best confirmed against a certificate of analysis for each batch.
Characterization of Selank in a laboratory setting relies on standard peptide methods. Reverse-phase high-performance liquid chromatography separates the target from related impurities and provides a purity figure, commonly reported as 95 percent or higher. Mass spectrometry, typically electrospray ionization or matrix-assisted laser desorption, confirms the molecular mass and helps detect truncation or modification. Amino acid analysis can verify composition when a sequence-level check is needed. These techniques together establish identity and purity for a given lot.
| 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 |
Reverse-phase high-performance liquid chromatography with ultraviolet detection near 214 nanometres is the standard purity method. Mass spectrometry, typically electrospray ionisation, confirms identity through the expected mass-to-charge pattern. Amino acid analysis can verify composition independently. Chiral purity requires separate techniques such as derivatisation followed by chromatographic separation, and such data are rarely reported for research-grade material.
Quantification in biological matrices relies on liquid chromatography coupled to tandem mass spectrometry with stable-isotope internal standards. Low plasma concentrations and adsorption to container surfaces both complicate measurement. Solid-phase extraction is often needed to reduce matrix interference before injection. Reported limits of quantification differ widely between laboratories, which makes direct comparison of pharmacokinetic results difficult and limits meta-analysis.
Proposed mechanisms centre on modulation of the GABAergic system, with reports of altered expression of genes related to GABA-A receptor subunits and changed monoamine turnover. Some studies describe inhibition of enkephalinase, the enzyme that degrades endogenous enkephalins, which may prolong opioid peptide signalling. Effects on brain-derived neurotrophic factor and on cytokine expression have also been reported. These findings come largely from animal models and small human studies, and the precise primary target remains unresolved.
Published clinical evidence is limited. Most controlled trials were conducted in Russia, enrolled modest numbers of participants, and appeared in Russian-language journals, which restricts independent verification. Reported outcomes include lower anxiety scores, improved attention and memory measures, and changes in fatigue ratings. Reviews written in English note methodological limitations such as small samples and inconsistent endpoints. Whether the compound produces clinically meaningful benefit relative to established anxiolytics is therefore an open question rather than an established finding.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro. It was designed at the Institute of Molecular Genetics of the Russian Academy of Sciences as a structural analogue of tuftsin, a naturally occurring tetrapeptide fragment of the immunoglobulin heavy chain. The added Pro-Gly-Pro tail was intended to slow enzymatic degradation and extend biological activity. In Russia it is registered as an anxiolytic nasal preparation, while regulators elsewhere have not approved it for clinical use.
Selank is a hydrophilic peptide and dissolves readily in water and in aqueous buffers. The lyophilised powder is typically a white to off-white solid. Because short peptides are prone to hydrolysis and oxidation, handling benefits from limiting exposure to heat, moisture and strong light. Working solutions are commonly prepared in sterile water or saline, and repeated freeze-thaw cycles are avoided to reduce aggregation and loss of activity. These practices reflect general laboratory convention rather than published stability specifications.
Dry powder is normally held at -20 degrees Celsius or lower, in a sealed container with desiccant and protection from light. Reconstituted solutions are usually kept at 2 to 8 degrees Celsius for short periods and frozen for longer ones. Proline residues at several positions are generally associated with some resistance to peptidase attack, but chemical stability still declines at neutral to alkaline pH and at elevated temperature. Exact shelf-life figures are product-specific and are not standardised across suppliers.
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.
=== Heart of stone === Severe forms of calciphylaxis may cause diastolic heart failure from cardiac calcification, called heart of stone. Widespread intravascular calcification typical of calciphylaxis lesions occur in the myocardium and prevent normal diastolic filling of the ventricles.
pnuC a NR/NMN transporter (most common; majority of Lactobacillales examples) nadA a Quinolate synthase (first committed step of de novo NAD⁺ biosynthesis; common in Planctomycetota) pncB a Nicotinate phosphoribosyltransferase (nicotinic acid salvage) ecf an ECF (energy-coupling factor) transporter cassette, likely involved in NAD⁺ homeostasis tsx a Nucleoside-specific channel
== Disadvantages == However, there is also the possibility that a tag added to a protein might obscure binding of the new protein to its interacting partners. In addition, the tag may also affect protein expression levels. On the other hand, the tag may also not be sufficiently exposed to the affinity beads, hence skewing the results. There may also be a possibility of a cleavage of the proteins by the TEV protease, although this is unlikely to be frequent given the high specificity of the TEV protease.
Electron ionization (EI, formerly known as electron impact ionization and electron bombardment ionization) is an ionization method in which energetic electrons interact with solid or gas phase atoms or molecules to produce ions. EI was one of the first ionization techniques developed for mass spectrometry. However, this method is still a popular ionization technique. This technique is considered a hard (high fragmentation) ionization method, since it uses highly energetic electrons to produce ions. This leads to extensive fragmentation, which can be helpful for structure determination of unknown compounds. EI is the most useful for organic compounds which have a molecular weight below 600 amu. Also, several other thermally stable and volatile compounds in solid, liquid and gas states can be detected with the use of this technique when coupled with various separation methods.
=== Prokaryotic === Predicted serpin genes are sporadically distributed in prokaryotes. In vitro studies on some of these molecules have revealed that they are able to inhibit proteases, and it is suggested that they function as inhibitors in vivo. Several prokaryote serpins are found in extremophiles. Accordingly, and in contrast to mammalian serpins, these molecules possess elevated resistance to heat denaturation. The precise role of most bacterial serpins remains obscure, although Clostridium thermocellum serpin localises to the cellulosome. It is suggested that the role of cellulosome-associated serpins may be to prevent unwanted protease activity against the cellulosome.
Sources: en.wikipedia.org
== Research == (R)-MDMA is under development separately by AtaiBeckley, Empath Biosciences (EmpathBio) and Definium Therapeutics (formerly MindMed). It is being developed by AtaiBeckley for social anxiety disorder, by Empath Biosciences for the treatment of PTSD and social phobia and it is being developed by Definium Therapeutics for the treatment of PDDs or autism. As of February 2026, the drug is in phase 2 clinical trials for social phobia and autistic spectrum disorders, whereas no recent development has been reported for PTSD. The results of AtaiBeckley's phase 2a trial for treatment of social phobia have been released, with the drug showing moderate effectiveness and a generally favorable safety profile for this indication.
Estradiol dienanthate (EDE), sold under the brand names Climacteron among others, is a long-acting estrogen medication which was previously used in menopausal hormone therapy for women and to suppress lactation in women. It was formulated in combination with estradiol benzoate (EB), a short-acting estrogen, and testosterone enanthate benzilic acid hydrazone (TEBH), a long-acting androgen/anabolic steroid. EDE has not been made available for medical use alone. The medication, in combination with EB and TEBH, was given by injection into muscle once or at regular intervals, for instance once every 6 weeks. Side effects of EDE include breast tenderness, breast enlargement, nausea, headache, and fluid retention. EDE is an estrogen and hence is an agonist of the estrogen receptor, the biological target of estrogens like estradiol. It is an estrogen ester and a prodrug of estradiol in the body. Because of this, it is considered to be a natural and bioidentical form of estrogen. EDE was first described by 1959. It was previously available in Canada and Germany but was discontinued by 2005. The medication is no longer available in any form.
β thalassemia major (Mediterranean anemia or Cooley anemia) is caused by a βo/βo genotype. No functional β chains are produced, and thus no hemoglobin A can be assembled. This is the most severe form of β-thalassemia. β thalassemia intermedia is caused by a β+/βo or β+/β+ genotype. In this form, some hemoglobin A is produced. β thalassemia minor is caused by a β/βo or β/β+ genotype. Only one of the two β globin alleles contains a mutation, so β chain production is not terribly compromised and patients may be relatively asymptomatic.
== Interactions == Due to its effect of reducing stomach acidity, use of pantoprazole can affect absorption of drugs that are pH-sensitive, such as ampicillin esters, ketoconazole, atazanavir, iron salts, amphetamine and mycophenolate mofetil. Additional medications that are affected include bisphosphonate derivatives, fluconazole, clopidogrel, and methotrexate.
In a meeting of the Quadrilateral Security Dialogue on the implications of the 2022 Russian invasion of Ukraine for the region, President Biden noted India's abstention, saying that most global allies were united against Russia. Speaking to the US Senate Foreign Relations Committee, US diplomat Donald Lu said the Biden administration was still considering sanctions against India over its S-400 deal with Russia, and its abstention at the UN. However, the Biden administration has ruled out secondary sanctions against India for its considerable oil imports or defence engagement from Russia.
Sources: en.wikipedia.org
Blood pH is regulated to stay within the narrow range of 7.35 to 7.45, making it slightly basic (compensation). Extra-cellular fluid in blood that has a pH below 7.35 is too acidic, whereas blood pH above 7.45 is too basic. A pH below 6.9 or above 7.8 is usually lethal. Blood pH, partial pressure of oxygen (pO2), partial pressure of carbon dioxide (pCO2), and bicarbonate (HCO3−) are carefully regulated by a number of homeostatic mechanisms, which exert their influence principally through the respiratory system and the urinary system to control the acid–base balance and respiration, which is called compensation. An arterial blood gas test measures these. Plasma also circulates hormones transmitting their messages to various tissues. The list of normal reference ranges for various blood electrolytes is extensive.
== Symbiosis == Anaerobic respiration and its end products can facilitate symbiosis between anaerobes and aerobes. This occurs across taxa, often in compensation for nutritional needs. Anaerobiosis and symbiosis are found in interactions between ciliates and prokaryotes. Anaerobic ciliates interact with prokaryotes in an endosymbiotic relationship. These relationships are mediated in which the ciliate leaves end products that its prokaryotic symbiont utilizes. The ciliate achieves this through fermentative metabolism. The rumen of various animals houses this ciliate alongside many other anaerobic bacteria, protozoans, and fungi. In specific, methanogenic archaea found in the rumen acts as a symbiont to anaerobic ciliates. These anaerobes are useful to those with a rumen due to their ability to break down cellulose, making it bioavailable when otherwise indigestible by animals. Termites utilize anaerobic bacteria to fix and recapture nitrogen. Specifically, the termite's hindgut is full of nitrogen-fixing bacteria, whose functions depend on the nitrogen concentration of the diet. Acetylene reduction in termites was observed to upregulate in termites with nitrogen-poor diets, meaning that nitrogenase activity rose as the nitrogen content of the termite was reduced. One of the functions of termite microbiota is to recapture nitrogen from the termite's uric acid. This allows nitrogen conservation from a diet otherwise low in nitrogen.
These games have no use, and they are harmful and a waste of time.” In 2016, Saleh al-Fawzan has issued other rulings that have drawn attention in Western media, including a fatwa reportedly prohibiting the mobile game Pokémon Go, which he classified as a form of gambling. He has also been reported to consider photography generally prohibited except when necessary. In 2017, he was reported to have referred to Shia Muslims as "brothers of Satan" and stated that they are "infidels" who "lie about God, his prophet, and the consensus of Muslims", remarks that have been cited as an example of sectarian rhetoric among some Saudi clerics. Al-Fawzan's supporters argue that his statements reflect traditional jurisprudence and adherence to Salafi teachings while critics contend that his pronouncements promote intolerance and discourage reform.
== Principle == Affinity chromatography has the advantage of specific binding interactions between the analyte of interest (normally dissolved in the mobile phase), and a binding partner or ligand (immobilized on the stationary phase). In a typical affinity chromatography experiment, the ligand is attached to a solid, insoluble matrix—usually a polymer such as agarose or polyacrylamide—chemically modified to introduce reactive functional groups with which the ligand can react, forming stable covalent bonds. The stationary phase is first loaded into a column to which the mobile phase is introduced. Molecules that bind to the ligand will remain associated with the stationary phase. A wash buffer is then applied to remove non-target biomolecules by disrupting their weaker interactions with the stationary phase, while the biomolecules of interest will remain bound. Target biomolecules may then be removed by applying a so-called elution buffer, which disrupts interactions between the bound target biomolecules and the ligand. The target molecule is thus recovered in the eluting solution. Affinity chromatography does not require the molecular weight, charge, hydrophobicity, or other physical properties of the analyte of interest to be known, although knowledge of its binding properties is useful in the design of a separation protocol. Types of binding interactions commonly exploited in affinity chromatography procedures are summarized in the table below.
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.
Reverse-phase HPLC is the usual method and gives a percentage purity value. Mass spectrometry then confirms the molecular mass. Together they provide a basic identity and purity profile for a lot.