Tuftsin raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
This page was last updated on 2026-01-20 and is reviewed periodically as new material appears.
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.
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.
Identity and purity are usually assessed by reversed-phase high-performance liquid chromatography, with mass spectrometry used to confirm molecular mass and sequence information. Amino acid analysis and peptide mapping may supplement these methods. Certified reference standards are scarce, and many commercial lots are sold as research chemicals without a pharmacopoeial monograph. Regulatory treatment differs by country: Selank is a registered prescription medicine in Russia, while in the European Union and the United States it is not an approved drug and may fall under research-chemical or unapproved-product frameworks.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular class | Synthetic heptapeptide | Stabilized analog of tuftsin |
| Sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Single-letter form: TKPRPGP |
| Molecular formula | C33H57N11O9 | Monoisotopic mass about 751.9 Da |
| Appearance | White to off-white powder | Typically supplied as lyophilized solid |
| Solubility | Freely soluble in water | Also soluble in common polar solvents |
Animal studies have examined behaviour in tests of anxiety, memory retention and stress response, and several report changes in neurotrophic or neurotransmitter-related markers. The human evidence base is much smaller, consisting mainly of short trials conducted in Russia with limited reporting in English-language journals. Sample sizes are modest and outcome measures vary between studies, so the findings are best described as preliminary. Independent replication under modern trial standards has not been widely reported.
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.
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.
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.
Reversed-phase high-performance liquid chromatography is the standard technique for estimating peptide purity. The result is a peak-area percentage, which describes how much of the detected material elutes as the main peak in one run. Mass spectrometry confirms the molecular mass and can reveal truncated, adducted, or otherwise modified species. Amino acid analysis or tandem mass spectrometry can address sequence fidelity when identity is in doubt. None of these measurements, taken alone, establishes that a sample is fit for any specific purpose.
Lyophilized selank is normally supplied as a dry powder and is considered stable for extended periods when kept cold and dry. Moisture uptake is the main practical threat, because absorbed water promotes both hydrolysis and aggregation in the solid state. Vials are usually warmed to room temperature before opening so that condensation does not form on the powder. Supplier documentation commonly specifies -20 °C for routine storage, with -80 °C used for material intended to be archived for years.
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.
As a missile passes through tissue, it decelerates, dissipating and transferring kinetic energy to the tissues. The velocity of the projectile is a more important factor than its mass in determining how much damage is done; kinetic energy increases with the square of the velocity. In addition to injury caused directly by the object that enters the body, penetrating injuries may be associated with secondary injuries, due for example to a blast injury. The path of a projectile can be estimated by imagining a line from the entrance wound to the exit wound, but the actual trajectory may vary due to ricochet or differences in tissue density. In a cut, the discolouration and the swelling of the skin from a blow happens because of the ruptured blood vessels and escape of blood and fluid and other injuries that interrupt the circulation.
=== International locations === The first location outside of North America opened in the United Kingdom on July 4, 2013, in London on Long Acre in Covent Garden. The chain now has more than 170 restaurants in the United Kingdom. In 2017, Five Guys opened its first restaurants in Germany, with a branch in Frankfurt and another in Essen. Five Guys opened its first Korean store in Gangnam, Seoul in 2023, with a countdown shout, and expanded to four branches in Seoul. In 2021, Five Guys opened their first location in Australia. The chain also has plans to expand into New Zealand. In 2025, Five Guys announced that it would open their first restaurant in Denmark, at Fisketorvet, a shopping mall in Copenhagen. In 2026, the number of stores per country was as follows:
Pournazarian's experience with GSD type 1b has been central to mobilizing millions of dollars in research funding and inspiring the establishment of dedicated foundations for advancing treatments. His family continues to be active in advocacy efforts, working with organizations such as CureGSD1b to support research and provide resources for affected families. (See inborn errors of carbohydrate metabolism for a full list of inherited diseases that affect glycogen synthesis, glycogen breakdown, or glucose breakdown.)
Discussions of radon concentrations in the environment refer to 222Rn, the decay product of uranium and radium. While the average rate of production of 220Rn (from the thorium decay series) is about the same as that of 222Rn, the amount of 220Rn in the environment is much less than that of 222Rn because of the short half-life of 220Rn (55 seconds, versus 3.8 days respectively). Radon concentration in the atmosphere is usually measured in becquerel per cubic meter (Bq/m3), the SI derived unit. Another unit of measurement common in the US is picocuries per liter (pCi/L); 1 pCi/L = 37 Bq/m3. Typical domestic exposures average about 48 Bq/m3 indoors, though this varies widely, and 15 Bq/m3 outdoors. In the mining industry, the exposure is traditionally measured in working level (WL), and the cumulative exposure in working level month (WLM); 1 WL equals any combination of short-lived 222Rn daughters (218Po, 214Pb, 214Bi, and 214Po) in 1 liter of air that releases 1.3 × 105 MeV of potential alpha energy; 1 WL is equivalent to 2.08 × 10−5 joules per cubic meter of air (J/m3). The SI unit of cumulative exposure is expressed in joule-hours per cubic meter (J·h/m3). One WLM is equivalent to 3.6 × 10−3 J h/m3. An exposure to 1 WL for 1 working-month (170 hours) equals 1 WLM cumulative exposure. The International Commission on Radiological Protection recommends an annual limit of 4.8WLM for miners. Assuming 2000 hours of work per year, this corresponds to a concentration of 1500 Bq/m3. 222Rn decays to 210Pb and other radioisotopes. The levels of 210Pb can be measured.
=== Laminar flow reactor === In a laminar flow reactor, the fluid flows through a long tube or parallel plate reactor and the flow is in layers parallel to the walls of the tube. The velocity of the flow is a parabolic function of radius. In the absence of molecular diffusion, the RTD is
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Upon activation, bAREs ADP-ribosylate any number of eukaryotic proteins; such mechanism is crucial to the instigation of the diseased states associated with ADP-ribosylation. GTP-binding proteins, in particular, are well-established in bAREs pathophysiology. For examples, cholera and heat-labile enterotoxin target the α-subunit of Gs of heterotrimeric GTP-binding proteins. As the α-subunit is ADP-ribosylated, it is permanently in an "active", GTP-bound state; subsequent activation of intracellular cyclic AMP stimulates the release of fluid and ions from intestinal epithelial cells. Furthermore, C. Botulinum C3 ADP-ribosylates GTP-binding proteins Rho and Ras, and Pertussis toxin ADP-ribosylates Gi, Go, and Gt. Diphtheria toxin ADP-ribosylates ribosomal elongation factor EF-2, which attenuates protein synthesis. There are a variety of bacteria which employ bAREs in infection: CARDS toxin of Mycoplasma pneumoniae, cholera toxin of Vibrio cholerae; heat-labile enterotoxin of E. coli; exotoxin A of Pseudomonas aeruginosa; pertussis toxin of B. pertussis; C3 toxin of C. botulinum; and diphtheria toxin of Corynebacterium diphtheriae.
The first flight of the US version, designated XP-51B took place in November 1942, but the USAAF had become so interested in the Merlin Mustang project that an initial contract for 400 aircraft was placed three months beforehand in August. The conversion led to production of the P-51B beginning at NAA's Inglewood, California, plant in June 1943, and P-51s started to become available to the 8th and 9th air forces in the winter of 1943–1944. Conversion to the two-stage supercharged and intercooled Merlin 60 series, over 350 lb (160 kg) heavier than the single-stage Allison, driving a four-bladed Hamilton Standard propeller, required moving the wing slightly forward to correct the aircraft's center of gravity. After the USAAF, in July 1943, directed fighter aircraft manufacturers to maximize internal fuel capacity, NAA calculated the P-51B's center of gravity to be forward enough to include an additional 85 US gal (320 L; 71 imp gal) fuel tank in the fuselage behind the pilot, greatly increasing the aircraft's range over that of the earlier P-51A. NAA incorporated the tank in the production of the P-51B-10, and supplied kits to retrofit it to all existing P-51Bs.
=== Minipreparation === Minipreparation of plasmid DNA is a rapid, small-scale isolation of plasmid DNA from bacteria. Commonly used miniprep methods include alkaline lysis and spin-column based kits. It is based on the alkaline lysis method. The extracted plasmid DNA resulting from performing a miniprep is itself often called a "miniprep". Minipreps are used in the process of molecular cloning to analyze bacterial clones. A typical plasmid DNA yield of a miniprep is 5 to 50 μg depending on the cell strain. Miniprep of a large number of plasmids can also be done conveniently on filter paper by lysing the cell and eluting the plasmid on to filter paper.
Often molecules do form multilayers, that is, some are adsorbed on already adsorbed molecules, and the Langmuir isotherm is not valid. In 1938 Stephen Brunauer, Paul Emmett, and Edward Teller developed a model isotherm that takes that possibility into account. Their theory is called BET theory, after the initials in their last names. They modified Langmuir's mechanism as follows:
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== History == Phytochelatin was first discovered in 1981 in fission yeast, and was named cadystin. It was then found in higher plants in 1985 and was named phytochelatin. In 1989 the biosynthetic enzyme, phytochelatin synthase, was discovered.
=== Characteristics of solid supports === The solid support consists of small (~50-to-100 micron diameter), polymeric resin beads functionalized with reactive groups (such as amine or hydroxyl groups) that can be used to attach the nascent peptide chain to the resin polymer. Most often, linker molecules are used to hold the peptide chains and resin together during synthesis. The peptide remains covalently attached to the resin support throughout the synthesis; after the chemical steps involved in adding each amino acid, excess reagents and soluble by-products can be removed by simple solvent washing and filtration. This approach circumvents the chromatographic isolation of the product peptide after each reaction step that is required when using conventional solution phase synthesis. Upon complete peptide synthesis, the linker molecule can be cleaved selectively to release the peptide.
=== Other adverse reactions === Adverse reactions may result from the poor quality of kava raw material used in the manufacturing of various kava products. Other adverse reactions from chronic use may include visual impairment, rashes or dermatitis, seizures, weight loss, and malnutrition, although there is limited high-quality research on these possible effects.
=== HPV-77 === The first successful strain to be used was the HPV-77, prepared by passing the virus through the cells of an African green monkey kidney 77 times. The efforts to develop the vaccine were conducted by a team of researchers at the National Institutes of Health's Division of Biologics Standards. Led by Harry M. Meyer and Paul D. Parkman, the team included Hope E. Hopps, Ruth L. Kirschstein, and Rudyard Wallace among others, the team began serious work on the vaccine with the arrival of a major rubella epidemic in the United States in 1964. Prior to arriving at the National Institutes of Health (NIH), Parkman had been working on isolating the rubella virus for the Army. He joined the laboratory of Harry Meyer. Parkman, Meyer, and the team from the NIH tested the vaccine at the Children's Colony in Conway, Arkansas in 1965 while a rubella epidemic still raged across the United States. This residential home provided care for children with cognitive disabilities and children who were ill. The ability to isolate children in their cabins and control access to the children made it an ideal location for testing a vaccine without starting an epidemic of rubella. Each of the children's parents provided consent for the participation in the trial. In June 1969, the NIH issued the first license for commercial production of the rubella vaccine to the pharmaceutical company Merck Sharp & Dohme. This vaccine made use of the HPV77 rubella strain and was produced in duck embryo cells.
Simcyp Limited was acquired March 13, 2012, by Certara inc. Simcyp Limited is a research-based company which provides modelling and simulation software to the pharmaceutical industry for use during drug development. Simcyp is based in Sheffield, UK. Simcyp's Simulators allow in silico prediction of drug absorption, distribution, metabolism excretion (ADME) and potential drug-drug interactions.
Sources: en.wikipedia.org
Selank is a synthetic heptapeptide designed as a stabilized analog of the natural tetrapeptide tuftsin. It has been investigated mainly for anxiolytic and cognitive effects. It is not an approved pharmaceutical in most countries.
It was developed in Russia, at the Institute of Molecular Genetics of the Russian Academy of Sciences, during the 1990s. Most published research originates from Russian institutions. Independent international replication remains limited.
Tuftsin is a natural tetrapeptide with the sequence Thr-Lys-Pro-Arg that participates in immune signaling. Selank extends that sequence with Pro-Gly-Pro at the C-terminus. The added residues are linked to greater resistance to enzymatic breakdown.
Dry powder is normally held at -20 degrees Celsius or below in a sealed, light-protected container with desiccant. Brief room-temperature handling during weighing is generally tolerated. Storage instructions vary between suppliers, so the accompanying certificate of analysis should be followed.