tuftsin comes up often in conversation and rarely with the context attached. Here we lay out the basics in order, then work through the practical considerations.
Last reviewed on 2026-06-20. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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 |
|---|---|---|
| Molecular formula | C33H57N11O9 | Free peptide form |
| Molecular mass | About 751.9 Da | Calculated average mass |
| Amino acid sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Single-letter form TKPRPGP |
| Structural basis | Tuftsin analogue | Extended version of a natural tetrapeptide |
| Development origin | Russian Academy of Sciences | Work carried out from the 1980s onward |
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.
Proposed mechanisms center on modulation of the GABA system, but no single molecular target has been confirmed. Rodent studies report changes in GABA-A receptor expression and in the turnover of serotonin, dopamine, and norepinephrine in several brain regions. Increases in brain-derived neurotrophic factor and its receptor have also been described after repeated administration. These findings come largely from animal models, and the degree to which they describe human neurochemistry remains an open question. The mechanism is best characterized as multi-system and not fully resolved.
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.
Peptide bonds are vulnerable to protease attack, and Selank is no exception. Measured half-life in serum is short, on the order of minutes in several reports, which explains why intranasal administration is the common route described in the literature. Absorption across the nasal mucosa partially bypasses first-pass hepatic metabolism. Quantitative data on human bioavailability remain limited and are difficult to compare across studies.
Lyophilised material kept dry at minus 20 degrees Celsius or colder is the most stable form, and suppliers commonly state a shelf life of two years or more under those conditions. Once dissolved, degradation accelerates through hydrolysis and deamidation, particularly at alkaline pH or elevated temperature. Working solutions are usually divided into single-use aliquots to avoid repeated freeze-thaw cycles. The choice of reconstitution solvent affects both stability and the ionic strength of the final preparation.
== Mechanism == Reticulocytosis results from the body's physiological response to an increased need for red blood cells. When red blood cells are destroyed or lost, tissues experience low oxygen levels causing the kidneys to release the hormone erythropoietin. Erythropoietin signals the bone marrow to accelerate the production of red blood cells through a process called erythropoiesis. As a result, more reticulocytes are released into the bloodstream. These immature cells continue to mature into fully developed red blood cells in circulation, restoring the red cell count and supporting oxygen delivery to tissues.
Amino acids are polymerised via peptide bonds to form a long backbone, with the different amino acid side chains protruding along it. In biological systems, proteins are produced during translation by a cell's ribosomes. Some organisms can also make short peptides by non-ribosomal peptide synthesis, which often use amino acids other than the encoded 22, and may be cyclised, modified and cross-linked.
In cardiology, the cardiac skeleton, also known as the fibrous skeleton of the heart, is a high-density homogeneous structure of connective tissue that forms and anchors the valves of the heart, and influences the forces exerted by and through them. The cardiac skeleton separates and partitions the atria (the smaller, upper two chambers) from the ventricles (the larger, lower two chambers). The heart's cardiac skeleton comprises four dense connective tissue rings that encircle the mitral and tricuspid atrioventricular (AV) canals and extend to the origins of the pulmonary trunk and aorta. This provides crucial support and structure to the heart while also serving to electrically isolate the atria from the ventricles. The unique matrix of connective tissue within the cardiac skeleton isolates electrical influence within these defined chambers. In normal anatomy, there is only one conduit for electrical conduction from the upper chambers to the lower chambers, known as the atrioventricular node. The physiologic cardiac skeleton forms a firewall governing autonomic/electrical influence until bordering the bundle of His which further governs autonomic flow to the bundle branches of the ventricles. Understood as such, the cardiac skeleton efficiently centers and robustly funnels electrical energy from the atria to the ventricles.
== Signs and symptoms == The following are symptoms characteristic with individuals having the disorder. Individuals may display some, most, or all of these symptoms throughout the course of their life, though symptoms may vary with each patient.
Alan Hutchinson Fairlamb, CBE, FRSE, FLS, FMedSci, FRSB (born 30 April 1947, Newcastle upon Tyne, England) is a Wellcome Trust Principal Research Fellow and Professor of Biochemistry in the Division of Biological Chemistry and Drug Discovery at the School of Life Sciences, University of Dundee, Scotland. From 2006-2011 he was a member of the Scientific and Technical Advisory Committee of the Special Programme for Research and Training in Tropical Diseases (TDR) -- an independent global programme of scientific collaboration co-sponsored by UNICEF, UNDP, the World Bank and WHO. Currently he is a member of the governing board of the Tres Cantos Open Lab Foundation, whose aim is to accelerate the discovery and development of medicines to tackle diseases of the developing world in an open collaborative manner. Fairlamb and his team have studied the protozoan parasites causing three different diseases - sleeping sickness, Chagas disease and leishmaniasis. He was one of the 250 scientists involved in the genome sequencing of these parasites. In 1985, Fairlamb discovered a unique thiol compound present in these parasites, and named it trypanothione. This thiol metabolite is quite different from its human equivalent, glutathione. Trypanothione allows the parasites to fend off free radicals and other toxic oxidants produced by the immune system of the infected patient, and was shown to be vital for parasite survival and virulence. For instance, antimonials neutralize the Leishmania parasite's antioxidant defence system, allowing the patient to clear the infection.
Sources: en.wikipedia.org
== January 15, 1982 (Friday) == The U.S. Federal Trade Commission dropped its 10-year-old antitrust lawsuit against the three largest makers of cereal in the nation— Kellogg, General Mills and General Foods. Hekuran Isai became the Minister of Internal Affairs for the People's Republic of Albania, as well as the director of the Communist nation's secret police, the Sigurimi, after the previous Internal Affairs Minister, Feçor Shehu, was arrested as part of a purge of government officials. The appointment came as the Albanian People's Assembly unanimously approved the appointment of Adil Çarçani as the new Prime Minister of Albania following the December 17 death by gunshot wound of Premier Mehmet Shehu. The Guatemalan Army invaded the village of Ilom (village) near Chajul and killed 28 men from the Mayan minority. A deadlier mass execution of 96 Mayan peasants would take place on March 23, 1982. The Lima Liturgy, drafted by Max Thurian, was celebrated in a multidenominational Christian gathering by the World Council of Churches Forbidden Broadway, an off-Broadway musical revue, written by Gerard Alessandrini and featuring parodies of current Broadway musicals, was given its first of 2,332 performances, opening at Palsson's Supper Club (now the Triad Theatre) in New York City. David Gibbons resigned as Premier of Bermuda and was succeeded by John Swan.
Christoph H. Borchers is a scientist specializing in proteomics and mass spectrometry. He is a professor in the Gerald Bronfman Department of Oncology at McGill University in Montreal, where he holds the Segal Chair in Molecular Oncology and directs the Segal Cancer Proteomics Centre and the Warren Y. Soper Clinical Proteomics Centre at the Lady Davis Institute of the Jewish General Hospital. Borchers works on mass spectrometry–based methods for quantitative and structural proteomics and on metabolomics, with applications in clinical research. Before moving to McGill he held the Don and Eleanor Rix BC Leadership Chair in Biomedical and Environmental Proteomics at the University of Victoria. He was elected a Fellow of the Canadian Academy of Health Sciences in 2013.
== Historiography == Berger, Henry W. ed. A William Appleman Williams Reader (1992). Ferrell, Robert H. Harry S. Truman and the Cold War Revisionists. (2006). 142 pp. excerpt and text search. Fitzpatrick, Sheila. "Russia's Twentieth Century in History and Historiography," The Australian Journal of Politics and History, Vol. 46, 2000. Gardner, Lloyd C. (ed.) Redefining the Past: Essays in Diplomatic History in Honor of William Appleman Williams (1986). Garthoff, Raymond L. "Foreign Intelligence and the Historiography of the Cold War." Journal of Cold War Studies 2004 6(2): 21–56. ISSN 1520-3972 Fulltext: Project MUSE. Isaac, Joel; Bell, Duncan, eds. Uncertain Empire: American History and the Idea of the Cold War (2012) online review by Victoria Hallinan. Kaplan, Lawrence S. American Historians and the Atlantic Alliance, (1991) online edition.. Kort, Michael. The Columbia Guide to the Cold War (1998). Matlock, Jack E. "The End of the Cold War" Harvard International Review, Vol. 23 (2001). Melanson, Richard A. "Revisionism Subdued? Robert James Maddox and the Origins of the Cold War" Political Science Reviewer, Vol. 7 (1977). Melanson, Richard A. Writing History and making Policy: The Cold War, Vietnam, and Revisionism (1983). Olesen, Thorsten B.Ed. The Cold War and the Nordic Countries: Historiography at a Crossroads. Odense: U Southern Denmark Press, 2004. Pp. 194. online review. Stephanson, Anders. American Imperatives: The Cold War and Other Matters, Verso Books, 2025 Suri, Jeremi.
Ricin has been involved in a number of actual or planned attacks on individuals. As of 2025, the only successful murder using ricin occurred in 1978. The Bulgarian dissident Georgi Markov was assassinated by Bulgarian secret police who surreptitiously shot him on a London street with what was later found to have been a modified umbrella using compressed gas to fire a tiny pellet containing ricin into his leg. He died in a hospital a few days later; his body was passed to a special poison branch of the British Ministry of Defence that discovered the pellet during an autopsy. The prime suspects were the Bulgarian secret police: Georgi Markov had defected from Bulgaria some years previously and had subsequently written books and made radio broadcasts that were highly critical of the Bulgarian communist regime. However, it was believed at the time that Bulgaria would not have been able to produce the pellet, and it was also believed that the KGB had supplied it. The KGB denied any involvement, although high-profile KGB defectors Oleg Kalugin and Oleg Gordievsky later claimed the KGB's involvement. Soviet dissident Aleksandr Solzhenitsyn developed (but survived) ricin-like symptoms after an encounter in 1971 with KGB agents. Ten days before the attack on Georgi Markov another Bulgarian defector, Vladimir Kostov, survived a similar attack. Kostov was standing on an escalator of the Paris metro when he felt a sting in his lower back above the belt of his trousers. He developed a fever, but recovered.
== Structure and basic properties == The N−C−C geometry is linear in nitriles, reflecting the sp hybridization of the triply bonded carbon. The C−N distance is short at 1.16 Å, consistent with a triple bond. Nitriles are polar, as indicated by high dipole moments. As liquids, they have high relative permittivities, often in the 30s.
Sources: en.wikipedia.org
It is a seven-amino-acid peptide, Thr-Lys-Pro-Arg-Pro-Gly-Pro, produced by chemical synthesis rather than extracted from biological tissue. Its design is based on tuftsin, a natural immunomodulatory tetrapeptide. The C-terminal Pro-Gly-Pro segment is a common stabilising motif in short regulatory peptides.
The core four residues correspond to tuftsin, which occurs naturally as part of immunoglobulin G. The full seven-residue sequence, however, is not a known endogenous peptide. It is a laboratory-designed analogue intended to combine tuftsin-like activity with greater resistance to breakdown.
No single receptor has been confirmed as the primary target. Reports describe involvement of the GABAergic system, interference with enkephalin degradation, and shifts in neurotrophic factor expression. Because these observations come from different models and assays, they have not yet been integrated into one accepted mechanism.
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.