Selank is one of those subjects where the details matter more than the headlines. This page pulls together the background, the mechanisms, and the practical points readers ask about most.
Last reviewed on 2026-05-03. 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.
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.
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.
| 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 |
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.
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.
Once dissolved, the peptide is markedly less stable than the dry powder. Aqueous solutions are subject to backbone hydrolysis and to microbial growth when they are handled without sterile technique. Buffered solutions near neutral pH are common for short-term laboratory work, while acidic conditions are sometimes used to improve solubility. Analytical laboratories generally prepare working solutions fresh rather than storing them, and a residual water film left in a reopened vial can seed degradation even when the container appears dry.
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.
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.
Inhibin B reaches a peak in the early- to mid-follicular phase, and a second peak at ovulation. Inhibin A reaches its peak in the mid-luteal phase. Inhibin secretion is diminished by GnRH, and enhanced by insulin-like growth factor-1 (IGF-1).
To import or export, sell or offer for sale, supply—even gratuitously—transport, carry, keep in storage, store, administer, or in any way deliver for consumption any narcotic substance, without authorization or in violation of legal or regulatory provisions. This article rendered these drugs illegal and thus authorized police powers and regulatory bodies to impose sanctions on users and traffickers of illicit drugs. Even before their legal prohibition, narcotic drugs were already shrouded in prejudice—particularly racial prejudice, such as in the case of marijuana, which was nicknamed "Angola weed", because it was mainly used by adherents of Afro-Brazilian religions in their rituals. In 1973, when Brazil acceded to the Convention on Psychotropic Substances, the "war on drugs" shifted its approach; the new drug policies clearly defined the penalties and consequences associated with possessing, purchasing, or selling these substances. It was in the Brazilian state's interest to marginalize and prohibit narcotics, given that during the 1968 student marches against the military dictatorship, drugs had been used as a symbol of resistance against the regime—and, due to the lack of clear penalties, users faced neither prosecution nor punishment.
However, correct DNA structure can form even when the bases are not paired via hydrogen bonding; that is, the bases pair thanks to hydrophobicity, as studies have shown with DNA isosteres (analogues with same number of atoms) such as the thymine analogue 2,4-difluorotoluene (F) or the adenine analogue 4-methylbenzimidazole (Z). An alternative hydrophobic pair could be isoquinoline and pyrrolo[2,3-b]pyridine. Other noteworthy basepairs:
The first fully terrestrial vertebrates were amniotes. Like their amphibious early tetrapod predecessors, they had lungs and limbs. Amniotic eggs, however, have internal membranes that allow the developing embryo to breathe but keep water in. Hence, amniotes can lay eggs on dry land, while amphibians generally need to lay their eggs in water. The first amniotes apparently arose in the Pennsylvanian subperiod of the Carboniferous. They descended from earlier reptiliomorph amphibious tetrapods, which lived on land that was already inhabited by insects and other invertebrates as well as ferns, mosses and other plants. Within a few million years, two important amniote lineages became distinct: the synapsids, which would later include the common ancestor of the mammals; and the sauropsids, which now include turtles, lizards, snakes, crocodilians and dinosaurs (including birds). Synapsids have a single hole (temporal fenestra) low on each side of the skull. Primitive synapsids included the largest and fiercest animals of the early Permian such as Dimetrodon. Nonmammalian synapsids were traditionally—and incorrectly—called "mammal-like reptiles" or pelycosaurs; we now know they were neither reptiles nor part of reptile lineage. Therapsids, a group of synapsids, evolved in the Middle Permian, about 265 million years ago, and became the dominant land vertebrates. They differ from basal eupelycosaurs in several features of the skull and jaws, including: larger skulls and incisors which are equal in size in therapsids, but not for eupelycosaurs.
=== Relationship with fibrocytes === Fibroblasts and fibrocytes are two states of the same cells, the former being the activated state, the latter the less active state, concerned with maintenance and tissue metabolism. Currently, there is a tendency to call both forms fibroblasts. The suffix "-blast" is used in cellular biology to denote a stem cell or a cell in an activated state of metabolism. Fibroblasts are morphologically heterogeneous with diverse appearances depending on their location and activity. Though morphologically inconspicuous, ectopically transplanted fibroblasts can often retain positional memory of the location and tissue context where they had previously resided, at least over a few generations. This remarkable behavior may lead to discomfort in the rare event that they stagnate there excessively.
Sources: en.wikipedia.org
== Classification == There are more than 20 types of reticular fibers. In Reticular Connective Tissue type III collagen/reticular fiber (100-150 nm in diameter) is the major fiber component. It forms the architectural framework of liver, adipose tissue, bone marrow, spleen and basement membrane, to name a few.
== Plot summary == Willie Somerset Chandran is the son of a Brahmin father and a Dalit mother. His father gave him his middle name as a homage to the English writer Somerset Maugham who had visited the father in the temple where the father was living under a vow of silence. Having come to despise his father for giving him a split identity, Willie leaves India to go to 1950s London to study. There he leads a life as a different man with an interesting background 'oriental' and fakes the facts of his life. Later in London he writes a book of short stories and manages to publish it. Willie receives a letter from Ana, a mixed Portuguese and black African girl, who admires his book, and they arrange to meet. They fall in love and Willie follows her to her country (an unnamed Portuguese colony in Africa, presumably Mozambique). Meanwhile, Willie's sister Sarojini marries a German and moves to Berlin. The novel ends with Willie having moved to his sister's place in Berlin after his 18-year stay in Africa. Having discovered that he's been living other people's lives and mimicking their behaviours to hide his past, it is implied at the end that he drops the mask and comes to peace with his background. Half a Life is a prequel to Naipaul's 2004 novel Magic Seeds which starts with Willie in Berlin.
==== Auditory system ==== Like all snakes, rattlesnakes lack external ear openings, and the structures of their middle ear are not as highly specialized as those of other vertebrates, such as mammals. Thus, their sense of hearing is not very effective, but they are capable of sensing vibrations in the ground, passed by the skeleton to the auditory nerve.
==== Campaign on the Pihe River (May–July 1933) ==== Liu deeply resented what he saw as Deng Xihou's betrayal, causing him to lose much territory in the Sichuan Basin. Not only did Deng order Tian to attack Liu's rear, but he had also taken over Chengdu in Liu's absence, blocking his return to the city. Liu had entrusted Deng with the city, but he had allowed Tian Songyao and his subordinates to reenter, including Wang Mingzhang who had become the Chengdu garrison commander. Both sides attempted negotiations while preparing their forces; Deng first attempted to appease Liu Wenhui, but Liu had by then resolved to crush him. Liu first attempted to lure Deng into a deadly banquet, but Deng caught wind of these plans and even taunted Liu about them. The battle began in May 1933 when Liu attacked along the Pihe River. Seeking support, Deng entered into talks with Liu Xiang's advisor Liu Congyun. By strategically converting to Liu Congyun's Taoist sect, Deng managed to acquire ammunition for his regiments and 100,000 silver dollars. Liu's officers also refused to fight against their former Baoding classmates, with some demanding more pay or even entering into negotiations with Deng's commanders. In June, heavy fighting was reported around Guanxian. By July, Liu Xiang had arrived in Neijiang to command a new offensive against Liu Wenhui. When Liu Wenhui convened a strategy meeting with his subordinates, several division commanders openly questioned his authority and leadership.
Clytia hemisphaerica reproduces sexually. Ovulated eggs are fertilized externally and take approximately 24 hours to develop into planula. The ciliated planula will swim freely until the proper external cues, for instance, experimental treatment with CsCl, trigger the metamorphic process. The planula can undergo its metamorphosis into a polyp as soon as three days after fertilization. Once the proper external cue is received, the planula stops swimming and attaches itself to a substrate via its aboral or aboral-lateral pole (what was previously the front end of the swimming planula). After attaching itself to a substrate, the planula contracts along its oral–aboral axis and so forms a flattened holdfast to anchor itself to the substrate.
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 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.