This is a working overview of Selank, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2026-07-21 and is reviewed periodically as new material appears.
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.
Peptide stability depends strongly on temperature, moisture, and pH. Lyophilized Selank is generally most stable when stored cold and dry, with freezer temperatures commonly used for long-term storage. In solution, the compound is susceptible to hydrolysis and to microbial growth if it is not handled aseptically. The C-terminal proline-rich extension appears to slow enzymatic cleavage relative to tuftsin, though quantitative degradation rates vary with the matrix and the conditions tested. Published stability data specific to Selank remain sparse.
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.
| 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 |
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.
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 studied chiefly as an animal-model anxiolytic with proposed secondary effects on memory and immune signaling. Reported mechanisms include modulation of the GABA-A receptor complex, inhibition of enkephalin-degrading enzymes, and shifts in monoamine turnover within limbic structures. Some experiments describe increased expression of brain-derived neurotrophic factor in the hippocampus after repeated dosing. No single molecular target has been confirmed, and the peptide does not bind any receptor with the selectivity typical of a conventional small-molecule drug. Mechanism therefore remains a set of hypotheses rather than an established pathway.
Laboratory work relies on standard behavioral paradigms. Rodents are tested in the elevated plus maze, open field, and passive avoidance tasks, with outcomes compared against diazepam or vehicle controls. Intranasal dosing is used most often because it bypasses first-pass metabolism, though intraperitoneal and intravenous routes also appear in published protocols. Biochemical endpoints include tissue BDNF concentrations, cytokine levels, and monoamine metabolites. Human data are limited to small Russian trials reporting reduced anxiety scores; most were not prospectively registered, and few employed independent outcome assessment.
Measuring peptide exposure inside the brain is technically difficult. Selank is degraded rapidly in plasma, and assays must separate intact peptide from fragments, which favors targeted mass spectrometry over immunoassays alone. Reported half-lives are short, on the order of minutes, so effects observed hours later are attributed to downstream signaling rather than to the parent compound. Blood-brain barrier permeability is debated and rarely quantified directly. Gaps include absent dose-response characterization, inconsistent reporting of purity, and almost no pharmacokinetic data from human participants.
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.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro, written TKPRPGP in one-letter notation. Its structure consists of the immunomodulatory tetrapeptide tuftsin, Thr-Lys-Pro-Arg, extended at the carboxyl terminus by a Pro-Gly-Pro segment. The molecular formula is commonly given as C33H57N11O9, corresponding to a monoisotopic mass near 751.4 Da and an average molecular mass near 751.9 Da. All seven residues are proteinogenic amino acids, and the molecule carries no modified side chains or non-natural linkages.
The compound was designed at the Institute of Molecular Genetics of the Russian Academy of Sciences during the 1980s and 1990s. The stated design goal was to retain the immunomodulatory and central nervous system activity attributed to tuftsin while improving resistance to enzymatic breakdown. Adding a proline-rich tail to the short parent peptide was a deliberate strategy, because proline residues restrict the conformations available to many peptidases. The same laboratory produced Semax, an ACTH fragment analog, and both compounds were developed in parallel as short, enzymatically stabilized peptides intended for intranasal use.
Selank is not a naturally occurring peptide and has no known endogenous counterpart in human physiology. Russian-language sources frequently call it TP-7, while English-language sources use the name Selank almost exclusively. Database indexing is uneven, partly because early reports appeared in regional journals that are not widely cataloged. Some summaries describe the material as a tuftsin analog and others as a synthetic heptapeptide; the labels overlap rather than conflict. Citing the primary sequence resolves ambiguity more reliably than the research or trade name alone.
== Side effects == Research indicates that cannabidiol may reduce adverse effects of THC, particularly those causing intoxication and sedation, but only at high doses. Safety studies of cannabidiol showed it is well tolerated, but may cause fatigue, somnolence, sedation, diarrhea, or changes in appetite as common adverse effects, with the most common being somnolence and sedation. Side effects of CBD are dose related. Epidiolex documentation lists sleepiness, insomnia and poor quality sleep, decreased appetite, diarrhea, and fatigue. In November 2019, the US Food and Drug Administration (FDA) issued concerns about the safety of cannabidiol, stating that CBD use has potential to cause hepatotoxicity, interfere with the mechanisms of prescription drugs, produce gastrointestinal disorders, or affect alertness and mood. In 2020–2023, the FDA updated its safety concerns about CBD, acknowledging the unknown effects of protracted use, how it affects the developing brain, fetus, or infants during breastfeeding, whether it interacts with dietary supplements or prescription drugs, whether male fertility is affected, and its possible side effects, such as drowsiness. As of September 2019, 1,085 people contacted US poison control centers about CBD-induced illnesses, doubling the number of cases over the 2018 rate and increasing by nine times the case numbers of 2017. Of cases reported in 2019, more than 33% received medical attention and 46 people were admitted to a hospital intensive care unit, possibly due to exposure to other products, or drug interactions with CBD.
Sir Henry Norris, the then Arsenal chairman, argued that Arsenal be promoted for their "long service to league football", having been the first League club from the South of England. It has been alleged that this was due to backroom deals and even outright bribery by Sir Henry Norris, colluding with his friend John McKenna, the chairman of Liverpool and the Football League, who recommended Arsenal's promotion at the AGM. No conclusive proof of wrongdoing has come to light, though other aspects of Norris's financial dealings unrelated to the promotion controversy have fuelled speculation on the matter. Norris resigned as chairman and left the club in 1929, having been found guilty by the Football Association of financial irregularities; he was found to have misused his expenses account, and to have pocketed the proceeds of the sale of the Arsenal team bus.
This is likely a result of defects in the corticotrophin hormone axis or other abnormalities with neurotransmission. Some patients may also have xanthomas, which are fat deposits that accumulate below the skin. These usually appear waxy and yellow, predominantly around the eyes and joints. This condition results from an accumulation of lipids within the blood. If gallstones prevent bile flowing from the pancreas to the small intestine, it can lead to gallstone pancreatitis. Physical symptoms include nausea, vomiting, and abdominal pain. Bile is required for the absorption of fat-soluble vitamins. As such, patients with cholestasis may present with a deficiency in vitamins A, D, E, or K due to a decline in bile flow. Patients with cholestasis may also experience pale stool and dark urine.
== Structural characteristics == The TCR is a disulfide-linked membrane-anchored heterodimeric protein normally consisting of the highly variable alpha (α) and beta (β) chains expressed as part of a complex with the invariant CD3 chain molecules. T cells expressing this receptor are referred to as α:β (or αβ) T cells, though a minority of T cells express an alternate receptor, formed by variable gamma (γ) and delta (δ) chains, referred as γδ T cells. Each chain is composed of two extracellular domains: Variable (V) region and a Constant (C) region, both of Immunoglobulin superfamily (IgSF) domain forming antiparallel β-sheets. The Constant region is proximal to the cell membrane, followed by a transmembrane region and a short cytoplasmic tail, while the Variable region binds to the peptide/MHC complex. The variable domain of both the TCR α-chain and β-chain each have three hypervariable or complementarity-determining regions (CDRs). There is also an additional area of hypervariability on the β-chain (HV4) that does not normally contact antigen and, therefore, is not considered a CDR. The residues in these variable domains are located in two regions of the TCR, at the interface of the α- and β-chains and in the β-chain framework region that is thought to be in proximity to the CD3 signal-transduction complex. CDR3 is the main CDR responsible for recognizing processed antigen, although CDR1 of the alpha chain has also been shown to interact with the N-terminal part of the antigenic peptide, whereas CDR1 of the β-chain interacts with the C-terminal part of the peptide.
Sources: en.wikipedia.org
== Biochemistry == Androgens like testosterone are responsible for penis enlargement and elongation during puberty. Penis size is positively correlated with increasing testosterone levels during puberty. But after puberty, administration of testosterone does not affect penis size, and androgen deficiency in adult men only results in a small decrease in size. Growth hormone (GH) and insulin-like growth factor 1 (IGF-1) are also involved in penis size, with deficiency (such as that observed in growth hormone deficiency or Laron syndrome) at critical developmental stages having the potential to result in micropenis.
== Bibliography == Allport, Alan (2015). Browned Off and Bloody-minded: The British Soldier Goes to War 1939–1945. New Haven: Yale University Press. ISBN 978-0-300-17075-7. Beckett, Ian F. W. Territorials: A Century of Service, first published April 2008 by DRA Printing of 14 Mary Seacole Road, The Millfields, Plymouth PL1 3JY on behalf of TA 100, ISBN 978-0-9557813-1-5 Bell, P. M. H. (1997) [1986]. The Origins of the Second World War in Europe (2nd ed.). London: Pearson. ISBN 978-0-582-30470-3. Campbell, John (2020). Haldane: The Forgotten Statesman Who Shaped Modern Britain. London: Hurst & Co. Dennis, Peter (1987). The Territorial Army. Woodbridge: The Royal Historical Society: Boydell Press.{{cite book}}: CS1 maint: publisher location (link) Dunlop, John K (1938). The development of the British Army 1899–1914. London: Methuen. Frederick, J. B. M. (1984). Lineage book of British land forces 1660-1978 : biographical outlines of cavalry, yeomanry, armour, artillery, infantry, marines and air force land troops of regular and reserve forces (Volume I). Wakefield: Microform Academic. ISBN 978-1-85117-007-4. OCLC 18072764. French, David (2001) [2000]. Raising Churchill's Army: The British Army and the War Against Germany 1919–1945. Oxford: Oxford University Press. ISBN 978-0-199-24630-4. Gibbs, N. H. (1976). Grand Strategy. History of the Second World War. Vol. I. London: HMSO. ISBN 978-0-116-30181-9. Gregory, Barry (2006). A History of the Artists Rifles 1859-1947. Barnsley: Pen and Sword. Heyman, M. A.
=== Patterns === In TCM, "pattern" (证; zhèng) refers to a "pattern of disharmony" or "functional disturbance" within the functional entities of which the TCM model of the body is composed. There are disharmony patterns of qi, xuě, the body fluids, the zàng-fǔ, and the meridians. They are ultimately defined by their symptoms and signs (i.e., for example, pulse and tongue findings). In clinical practice, the identified pattern usually involves a combination of affected entities (compare with typical examples of patterns). The concrete pattern identified should account for all the symptoms a person has.
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.
The most common approach combines reverse-phase liquid chromatography with mass spectrometry. Chromatography separates the components while mass spectrometry confirms the molecular mass. Peptide sequencing or tandem mass analysis can further verify the amino acid order.