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Identity And Structural Background — Evidence Review

By Editorial Desk · published 2026-07-27 · last reviewed 2026-08-01 · Data

Everything below concerns Selank. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.

Updated 2026-08-01. Numbers and descriptions here follow the published literature rather than marketing material.

Identity and Structural Background

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.

Development work on the compound began in the 1980s and 1990s at the Institute of Molecular Genetics in Moscow, within the same research programme that produced the peptide Semax. Early investigators sought a tuftsin derivative with improved resistance to enzymatic breakdown and with activity in the central nervous system after peripheral administration. Most of the primary literature from this period was published in Russian, a factor that still shapes how easily the findings can be checked by outside groups.

Selank Handling, Stability, and Analysis

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.

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.

Selank at a glance

PropertyValueNotes
Chemical classSynthetic heptapeptideTuftsin analogue
SequenceThr-Lys-Pro-Arg-Pro-Gly-ProSingle-letter form: TKPRPGP
Molecular formulaC33H57N11O9Calculated for the free peptide
Molecular weightAbout 751.9 g/molDerived from the sequence
AppearanceWhite to off-white powderTypical lyophilised form

Administration, Testing and Availability

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.

Related pages on this site

Selank Background And Chemical Identity

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.

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.

Supporting material

== Further reading == Thakkar, Santosh V.; Allegre, Kevin M.; Joshi, Sangeeta B.; Volkin, David B.; Middaugh, C. Russell (2012). "An application of ultraviolet spectroscopy to study interactions in proteins solutions at high concentrations". Journal of Pharmaceutical Sciences. 101 (9): 3051–3061. Bibcode:2012JPhmS.101.3051T. doi:10.1002/jps.23188. ISSN 0022-3549. PMID 22581726. Scott Huffman, Keyur Soni and Joe Ferraiolo UV-Vis Based Determination of Protein Concentration: Validating and Implementing Slope Measurements Using Variable Pathlength Technology by September 2014 http://www.bioprocessintl.com/manufacturing/antibody-non-antibody/uv-vis-based-determination-protein-concentration-validating-implementing-slope-measurements-using-variable-pathlength-technology/

Voters consistently cited the economy as their top issue in the 2024 election. Following the COVID-19 pandemic, a global surge in inflation ensued that raised prices on many goods, although the U.S. inflation rate had declined significantly during 2023 and 2024. The New York Times reported that both candidates "embraced a vision of a powerful federal government, using its muscle to intervene in markets in pursuit of a stronger and more prosperous economy". The Wall Street Journal reported that economists found Trump's proposed policies created a greater risk of stoking inflation and generating higher budget deficits, relative to the Harris plan. Twenty-three Nobel Prize-winning economists signed a letter characterizing the Harris economic plan as "vastly superior" to the Trump plan. Trump's designated government efficiency leader Elon Musk said in October that he expected Trump's plan would involve more than $2 trillion in federal spending cuts and would cause "some temporary hardship." Harris ran on a pro-union platform. She promoted the passage of the Infrastructure Investment and Jobs Act, funding for small business, and previously supported an act as senator to provide a $6,000 tax credit for middle and low-income families. Harris promised to address price gouging, bring down costs, ban hidden fees and late charges from financial institutions, limit "unfair" rent increases and cap prescription drug costs, which she said would "lower costs and save many middle-class families thousands of dollars a year".

=== EC 1.4.1 With NAD+ or NADP+ as acceptor === EC 1.4.1.1: alanine dehydrogenase EC 1.4.1.2: glutamate dehydrogenase EC 1.4.1.3: glutamate dehydrogenase (NAD(P)+) EC 1.4.1.4: glutamate dehydrogenase (NADP+) EC 1.4.1.5: L-amino-acid dehydrogenase EC 1.4.1.6: deleted, Now included with EC 1.21.4.1, D-proline reductase (dithiol) EC 1.4.1.7: serine 2-dehydrogenase EC 1.4.1.8: valine dehydrogenase (NADP+) EC 1.4.1.9: leucine dehydrogenase EC 1.4.1.10: glycine dehydrogenase EC 1.4.1.11: L-erythro-3,5-diaminohexanoate dehydrogenase EC 1.4.1.12: 2,4-diaminopentanoate dehydrogenase EC 1.4.1.13: glutamate synthase (NADPH) EC 1.4.1.14: glutamate synthase (NADH) EC 1.4.1.15: lysine dehydrogenase EC 1.4.1.16: diaminopimelate dehydrogenase EC 1.4.1.17: N-methylalanine dehydrogenase EC 1.4.1.18: lysine 6-dehydrogenase EC 1.4.1.19: tryptophan dehydrogenase EC 1.4.1.20: phenylalanine dehydrogenase EC 1.4.1.21: aspartate dehydrogenase EC 1.4.1.22: there is no overall consumption of NAD+ during the reaction. As a result, transfer of the enzyme from EC 4.3.1.12 was not necessary and EC 1.4.1.22 was withdrawn before being made official EC 1.4.1.23: valine dehydrogenase (NAD+) EC 1.4.1.24: 3-dehydroquinate synthase II EC 1.4.1.25: L-arginine dehydrogenase EC 1.4.1.26: 2,4-diaminopentanoate dehydrogenase (NAD+) EC 1.4.1.27: glycine cleavage system

Sources: en.wikipedia.org

Notes from published material

Zionism arose in the late 19th century in reaction to anti-Semitic and exclusionary nationalist movements in Europe. Romantic nationalism in Central and Eastern Europe had helped to set off the Haskalah, or "Jewish Enlightenment", creating a split in the Jewish community between those who saw Judaism as their religion and those who saw it as their ethnicity or nation. The 1881–1884 anti-Jewish pogroms in the Russian Empire encouraged the growth of the latter identity, resulting in the formation of the Hovevei Zion pioneer organizations, the publication of Leon Pinsker's Autoemancipation, and the first major wave of Jewish immigration to Palestine – retrospectively named the "First Aliyah".

==== Animal substances ==== Some animal parts used include cow gallstones, hornet nests, leeches, and scorpion. Other examples of animal parts include horn of the antelope or buffalo, deer antlers, testicles and penis bone of the dog, and snake bile. Some TCM textbooks still recommend preparations containing animal tissues, but there has been little research to justify the claimed clinical efficacy of many TCM animal products. 968+8956

Latin and Greek were the primary languages of the late Roman Empire, with the former prevalent in the west and the latter in the east. Although Latin was historically important in the military, legal system, and government, its use declined in Byzantine territories from 400 AD. Greek had begun to replace it even in those functions by the time of Justinian I (r. 527–565), who may have tried to arrest Latin's decline. Its extinction in the east was thereafter inevitable. A similar process of linguistic Hellenization occurred in Asia Minor, whose inhabitants had mostly abandoned their indigenous languages for Greek by early Byzantine times. Still, much of the population of the early empire would have known neither Latin nor Greek, especially in rural areas—their languages included Armenian in Byzantine Armenia, Aramaic dialects such as Syriac in Mesopotamia and the Levant, Coptic in Egypt, Phoenician on the Levant coast and in Carthage, and Berber in rural North Africa. By the mid-6th century, Geoffrey Horrocks estimates that Greek was the native language of about one-third of the population, while it was spoken by 80% of the aristocracy. The empire lost its linguistic diversity in the wars of the 7th and 8th centuries, becoming overwhelmingly Greek-speaking. During this troubled period, classical Attic Greek—one of the linguistic registers the Byzantine Greeks inherited—fell out of use, while the everyday vernacular registers were still used.

↓: reduced serum concentration or structure parameter; ↑: increased serum concentration or structure parameter; ↔: no change; TSH: Thyroid-stimulating hormone; T3: Total triiodothyronine; T4: Total thyroxine; fT4: Free thyroxine; fT3: Free triiodothyronine; rT3: Reverse triiodothyronine

Sources: en.wikipedia.org

Further detail

=== Wild-type (ATTRwt-CM) === This type has no mutations in the TTR gene but TTR deposits still form in the heart and other tissues. Males are more commonly affected, at ages over 70 years. Carpal tunnel syndrome may form as well as amyloid deposits in the carpal tunnel causing compression of the median nerve. Amyloid deposits in the carpal tunnel or other ligaments (causing tendon rupture) or the spinal canal causing spinal stenosis may precede the development of heart failure by 10-15 years. Wild type ATTR cardiac amyloidosis (and the genetic variant) can be diagnosed with cardiac nuclear scintigraphy to visualize amyloid deposits in the heart walls. Serum free light chains, serum and urine electrophoresis with immunofixation can rule out AL amyloidosis. If the diagnosis is unclear, a biopsy may be obtained. Biopsy with histological evaluation can rule out light chain and genetic testing can rule out familial subtypes. This type is often misdiagnosed. However, greater use of cardiac magnetic resonance has increased the rate of diagnosis. The severity of the disease tends to be less than the light chain and familial variants. This is due to the amount of time that it takes to accumulate the amyloid depositions being longer in the wild-type variant.

In A&P's traditional grocery stores, "wages and overhead expenses" had consumed 18 percent of sales, while in A&P's newly opened supermarkets in those same neighborhoods, those same numbers were less than 12 percent of sales. Once the large chains joined the supermarket trend, the new retail format exploded across the country like a wildfire. The number of American supermarkets almost tripled from 1,200 in 32 states in 1936 to over 3,000 in 47 states in 1937. It was well over 15,000 by 1950. One sign of the supermarket format's success in slashing labor costs, overhead, and food prices was that the percentage of disposable income spent by American consumers on food plunged "from 21 percent in 1930 to 16 percent in 1940". The modern era of "cheap food" had begun. As large chain stores began to dominate the American grocery landscape with their low overhead and low prices (while crushing numerous independent small stores along the way), a backlash to this radical alteration of food distribution infrastructure appeared in the form of numerous anti-chain campaigns. The idea of "monopsony", proposed by Cambridge economist Joan Robinson in 1933, that a single buyer could outmaneuver a market of multiple sellers, became a strong anti-chain rhetorical device. With public backlash came political pressure to even the playing field for smaller vendors lacking the luxury of economies of scale.

== Consumer acceptance == Historically, consumers paid little attention to food technologies. Nowadays, the food production chain is long and complicated and food technologies are diverse. Consequently, consumers are uncertain about the determinants of food quality and find it difficult to understand them. Now, acceptance of food products very often depends on perceived benefits and risks associated with food. Popular views of food processing technologies matter. Especially innovative food processing technologies often are perceived as risky by consumers. Acceptance of the different food technologies varies. While pasteurization is well recognized and accepted, high pressure treatment and even microwaves often are perceived as risky. Studies by the Hightech Europe project found that traditional technologies were well accepted in contrast to innovative technologies. Consumers form their attitude towards innovative food technologies through three main mechanisms: First, through knowledge or beliefs about risks and benefits correlated with the technology; second, through attitudes based on their own experience; and third, through application of higher order values and beliefs. A number of scholars consider the risk-benefit trade-off as one of the main determinants of consumer acceptance, although some researchers place more emphasis on the role of benefit perception (rather than risk) in consumer acceptance.

Sources: en.wikipedia.org

Frequently asked questions

What is the peptide sequence of Selank?

The sequence is Thr-Lys-Pro-Arg-Pro-Gly-Pro, commonly written as TKPRPGP. It shares the first four residues with tuftsin and carries three prolines in the chain. The proline-rich tail is the main structural feature that separates it from the parent tetrapeptide.

How is it related to tuftsin?

Selank is a synthetic analogue built on the tuftsin tetrapeptide Thr-Lys-Pro-Arg. Extra proline residues were added to the C-terminus during design work. That modification is intended to make the peptide less vulnerable to rapid enzymatic degradation.

Why do different sources use different names?

Transliteration from Russian produces variant spellings such as Selanc. Many suppliers avoid the trade-style name entirely and list the peptide sequence. Comparing sequences rather than names is the reliable way to confirm two entries describe the same molecule.

How should selank powder be stored?

Sealed, desiccated storage at -20 °C or colder is the standard recommendation for research-grade material. Vials should reach room temperature before they are opened, which limits condensation. Repeated temperature cycling is discouraged.

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