Everything below concerns heptapeptide. 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.
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.
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.
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.
| 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 |
Quality assessment of Selank samples typically combines purity determination with identity confirmation and counter-ion analysis. Purity is usually reported as a percentage by chromatographic area, with values above 95 percent often quoted for research-grade material. Water content and residual solvents are checked in lyophilized batches because they affect both stability and accurate mass determination. A reported purity figure does not by itself establish that a sample is the intended sequence, so orthogonal methods are needed to rule out sequence isomers or truncation products.
Characterization of Selank in laboratory settings relies on standard peptide analytical techniques. Reverse-phase high-performance liquid chromatography separates the peptide from related impurities and degradation products, while mass spectrometry confirms molecular identity through accurate mass measurement. Amino acid analysis and peptide sequencing verify the primary structure when reference material is unavailable. Because Selank is a short chain, fragmentation-based analysis produces a diagnostic ion pattern that supports confident identification.
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.
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.
The therapeutic uses of puffer fish (tetraodon) eggs were mentioned in the first Chinese pharmacopoeia Pen-T'so Ching (The Book of Herbs, allegedly 2838–2698 BC by Shennong; but a later date is more likely), where they were classified as having "medium" toxicity, but could have a tonic effect when used at the correct dose. The principal use was "to arrest convulsive diseases". In the Pen-T'so Kang Mu (Index Herbacea or The Great Herbal by Li Shih-Chen, 1596) some types of the fish Ho-Tun (the current Chinese name for tetraodon) were also recognized as both toxic yet, at the right dose, useful as part of a tonic. Increased toxicity in Ho-Tun was noted in fish caught at sea (rather than river) after the month of March. It was recognized that the most poisonous parts were the liver and eggs, but that toxicity could be reduced by soaking the eggs. (Tetrodotoxin is slightly water-soluble, and soluble at 1 mg/ml in slightly acidic solutions.) The German physician Engelbert Kaempfer, in his "A History of Japan" (translated and published in English in 1727), described how well known the toxic effects of the fish were, to the extent that it would be used for suicide and that the Emperor specifically decreed that soldiers were not permitted to eat it. There is also evidence from other sources that knowledge of such toxicity was widespread throughout southeast Asia and India. The first recorded cases of TTX poisoning affecting Westerners are from the logs of Captain James Cook from 7 September 1774. The crew received a fish from the New Caledonia natives.
=== 18 May === Fourteen people were killed by RSF shelling on a market in the Abu Shouk camp. One person was killed in an RSF attack on the village of Al-Samra in White Nile State. Nine people, including seven military personnel, were killed in an RSF drone strike on a base belonging to the Sudan Shield Forces in the Al-Butana plain of Gezira State.
==== Impact of phonation ==== The viscoelastic properties of human vocal fold lamina propria are essential for their vibration, and depend on the composition and structure of their extracellular matrix. Adult vocal cords have a layered structure which is based on the layers differential in extracellular matrix distribution. Newborns on the other hand, do not have this layered structure. Their vocal cords are uniform, and immature, making their viscoelastic properties most likely unsuitable for phonation. Hyaluronic acid plays a very important role in the vocal fold biomechanics. In fact, hyaluronic acid has been described as the extracellular matrix molecule that not only contributes to the maintenance of an optimal tissue viscosity that allows phonation, but also of an optimal tissue stiffness that allows frequency control. CD44 is a cell surface receptor for HA. Cells such as fibroblasts are responsible for synthesizing extracellular matrix molecules. Cell surface matrix receptors in return, feed back to the cells through cell-matrix interaction, allowing the cell to regulate its metabolism. Sato et al. carried out a histopathologic investigation of unphonated human vocal cords. Vocal fold mucosae, which were unphonated since birth, of three young adults (17, 24, and 28 years old) were looked at using light and electron microscopy. The results show that the vocal fold mucosae were hypoplastic, and rudimentary, and like newborns, did not have any vocal ligament, Reinke's space, or layered structure. Like newborns, the lamina propria appeared as a uniform structure.
=== Driver behavior === Highly developed fleet management and vehicle telematics systems collect a full range of data in real-time and for transport and fleet managers. By combining received data from the vehicle tracking system and the on-board computer, it is possible to form a profile for any given driver (average speed, frequency of detours, breaks, severity of manoeuvres, choice of gears, etc.). This data can be used to highlight drivers with dangerous habits and to suggest remedial training applicable to the issues, or to ensure that drivers are meeting KPIs. Fleet management apps have shown to reduce driving incidents.
Sources: en.wikipedia.org
=== Americas === The Americas were more highly influenced by the Doctrine of Signatures than China, India, or Africa, most likely because of their colonial history with Europe. The majority of insect use in medicine is associated with Central America and parts of South America, rather than North America, and most of it is based on the medical techniques of indigenous peoples. Currently, insect medicine is practiced much more rarely than in China, India, or Africa, though it is still relatively common in rural areas with large indigenous populations. Some examples to follow: Chapulines, or grasshoppers, are commonly consumed as a toasted regional dish in some parts of Mexico, but they are also used medicinally. They are said to serve as diuretic to treat kidney diseases, to reduce swelling, and to relieve the pain of intestinal disorders when they are consumed. However, there are some risks associated with consuming chapulines, as they are known to harbor nematodes which may be transmitted to humans upon consumption. Much like the termites of Africa, ants were sometimes used as medicinal devices by the indigenous peoples of Central America. The soldier cast of the Army ant would be collected and used as living sutures by Mayans. This involved agitating an ant and holding its mandibles up to the wound edges; when it bit down, the thorax and abdomen were removed, leaving the head holding the wound together. The ant's salivary gland secretions were reputed to have antibiotic properties.
== Toxicity == The US Food and Nutrition Board has set a daily limit of 35 mg for vitamin B3, unless under medical supervision. At daily doses of nicotinic acid as low as 30 mg, flushing has been reported, always starting in the face and sometimes accompanied by skin dryness, itching, paresthesia, and headache. (These effects do not occur with nicotinamide). Liver toxicity is the most serious toxic reaction and it occurs at doses >2 grams/day, and is possible with either nicotinic acid or nicotinamide. Fulminant hepatic failure has been reported in cases of niacin overdose at several grams per day. Other reactions include glucose intolerance, hyperuricemia, macular edema, and macular cysts.
=== Motility assays === Agarose is sometimes used instead of agar to measure microorganism motility and mobility. Motile species will be able to migrate, albeit slowly, throughout the porous gel and infiltration rates can then be visualized. The gel's porosity is directly related to the concentration of agar or agarose in the medium, so different concentration gels may be used to assess a cell's swimming, swarming, gliding and twitching motility. Under-agarose cell migration assay may be used to measure chemotaxis and chemokinesis. A layer of agarose gel is placed between a cell population and a chemoattractant. As a concentration gradient develops from the diffusion of the chemoattractant into the gel, various cell populations requiring different stimulation levels to migrate can then be visualized over time using microphotography as they tunnel upward through the gel against gravity along the gradient.
Mathematical chemistry – area of study engaged in novel applications of mathematics to chemistry. It concerns itself principally with the mathematical modeling of chemical phenomena. Mechanochemistry – coupling of mechanical and chemical phenomena on a molecular scale. Molecular biology – study of interactions between the various systems of a cell. It overlaps with biochemistry. Petrochemistry – study of the transformation of petroleum and natural gas into useful products or raw materials. Phytochemistry – study of phytochemicals which come from plants. Radiochemistry – chemistry of radioactive materials. Sonochemistry – study of effect of sonic waves and wave properties on chemical systems. Synthetic chemistry – study of chemical synthesis.
SCID mice were and still are used in disease, vaccine, and transplant research, especially as animal models for testing the safety of new vaccines or therapeutic agents in people with weakened immune system. SCID mice also serve as a useful animal model in the study of the human immune system and its interactions with disease, infections, and cancer. For example, normal strains of mice can be lethally irradiated, killing all rapidly dividing cells. These mice then receive bone marrow transplantation from SCID donors, allowing engraftment of human peripheral blood mononuclear cells (PBMC) to occur. This method can be used to study whether T cell-lacking mice can perform hematopoiesis after receiving human PBMC. A recessive gene, with clinical signs similar to the human condition, affects the Arabian horse. The condition remains a fatal disease, as the horse inevitably succumbs to an opportunistic infection within the first four to six months of life. However, carriers, who themselves are not affected by the disease, can be detected with a DNA test. Therefore, careful breeding practices can avoid the risk of an affected foal being produced. Another animal with well-characterized SCID pathology is the dog. There are two known forms: an X-linked SCID in Basset Hounds that has similar ontology to X-SCID in humans and an autosomal recessive form seen in one line of Jack Russell Terriers that is similar to SCID in Arabian horses and mice.
Sources: en.wikipedia.org
=== Phase II - conjugation === In subsequent phase II reactions, these activated xenobiotic metabolites are conjugated with charged species such as glutathione (GSH), sulfate, glycine, or glucuronic acid. These reactions are catalysed by a large group of broad-specificity transferases, which in combination can metabolise almost any hydrophobic compound that contains nucleophilic or electrophilic groups. One of the most important of these groups are the glutathione S-transferases (GSTs). The addition of large anionic groups (such as GSH) detoxifies reactive electrophiles and produces more polar metabolites that cannot diffuse across membranes, and may, therefore, be actively transported.
Gabapentinoids, also known as α2δ subunit-containing voltage-gated calcium channel ligands, include drugs like gabapentin, pregabalin, and gabapentin enacarbil. They have been found to increase slow wave sleep (deep sleep) in people with insomnia and healthy individuals. However, they do not appear to improve sleep onset. The gabapentinoid atagabalin (PD-0200390) was under formal development for treatment of insomnia, but development was discontinued following unsatisfactory clinical trial results. PD-0299685 is another gabapentinoid that was under development for the treatment of insomnia, specifically that related to menopausal symptoms, but its development was discontinued similarly.
== Applications == DART is being applied in many fields, including the fragrance industry, pharmaceutical industry, foods and spices, forensic science and health, materials analysis, etc. In forensic science, DART is used for analysis of explosives, warfare agents, drugs, inks and sexual assault evidence. In clinical and pharmaceutical sector, DART is utilized for body fluid analysis such as blood, plasma, urine etc. and study traditional medicines. Also DART can detect composition in medicine in a tablet form as per there is no need for sample preparation such as crushing or extracting. In food industry, DART assures the quality and authenticity assessment of food. It is also used in the analysis of mycotoxins in beverages, semi-quantitative analysis of caffeine, monitoring heat accelerated decomposition of vegetable oils and many other food safety analysis. In the manufacturing industry, to determine the deposition and release of a fragrance on surfaces such as fabric and hair and dyes in textiles, DART is often utilized. DART is used in environmental analysis. For example, analysis of organic UV filters in water, contaminants in soil, petroleum products and aerosols etc. DART also plays an important role in biological studies. It enables studying chemical profiles of plants and organisms.
=== Pharmacokinetics === A study comprehensively reviewed the metabolism of 3-HO-PCE by using human liver microsomes and samples, both biological and non-biological, from a volunteer. The first major metabolic pathway involves N-dealkylation, yielding the primary amine metabolite 3-HO-PCA. The second pathway causes the molecule to undergo oxidation, creating phenol-3-HO-PCE and hydroxy-3-HO-PCE. These compounds then undergo dehydration, creating dehydro-3-HO-PCE (which is also created directly from the parent compound via dehydrogenation). The third pathway causes the parent compound to undergo oxidative deamination, creating 1-(3'-hydroxyphenyl) cyclohexanol. This compound can either undergo oxidation and dehydrogenation to form dihydroxy-[1,1'-bi(cyclohexan)]-1-en-3-one, or a pathway involving dehydration and allylic oxidation to eventually form 3'4'-dihydro-[1,1'-biphenyl]-3-ol. The fourth pathway is phase II conjugation, where the parent compound undergoes O-glucuronidation to form 3-OGlu-PCE.
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.
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.