Tuftsin analogue raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
Reviewed 2026-01-08. Anything still debated is marked as such rather than presented as settled.
Published clinical work is concentrated in Russian-language journals and generally involves small samples without independent replication. Systematic reviews in English note the shortage of randomised, placebo-controlled trials and the difficulty of verifying methods from translated reports. Outcome measures vary between studies, which complicates pooling of results. Interest in the compound as a cognitive or anxiolytic agent therefore rests on a thinner evidence base than the volume of citations suggests. Replication in well-powered trials with preregistered endpoints would be needed before firm conclusions about efficacy can be drawn.
Proposed mechanisms centre on the GABAergic system. Animal and tissue studies report changes in GABA-A receptor expression and reduced activity of GABA transaminase, the enzyme that degrades GABA. Effects on monoamine turnover, including serotonin and dopamine pathways, are also described, and a separate line of work links the peptide to increased expression of brain-derived neurotrophic factor in hippocampal tissue. Most of these findings come from rodent models and cell preparations. How the individual observations combine into a single coherent mode of action is not settled.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Primary route studied | Intranasal | Also examined parenterally in animal work |
| Reported plasma half-life | Minutes to tens of minutes | Values vary widely between reports |
| Main model systems | Rodent behavioural and cell assays | Human trials are few and small |
| Principal proposed targets | GABA-A receptor, GABA transaminase | Monoamine and neurotrophic pathways also reported |
| Evidence grade | Preliminary | Limited independent replication |
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.
Lyophilized Selank, the dry powder form, is generally stored frozen at minus 20 degrees Celsius or colder for long-term keeping. The solid is hygroscopic and should stay sealed, dry, and protected from light. Once dissolved, the peptide is less stable and is usually held refrigerated at 2 to 8 degrees Celsius for short periods. Repeated freezing and thawing is avoided because it can promote aggregation and loss of activity. Buffers and pH choice also affect how long a solution remains usable.
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.
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.
IUPAC organic nomenclature has three main parts: the substituents, carbon chain length, and chemical affix. The substituents are any functional groups tied to the main carbon chain. The main carbon chain is the longest possible continuous chain. The chemical affix denotes what type of molecule it is. For example, the ending ane conveys a single bonded carbon chain, as in "hexane" (C6H14). Another example of IUPAC organic nomenclature is cyclohexanol:
== Current practice == The most definitive method to determine whether a particle is characteristic of GSR is by its elemental profile. GSR mostly derives from its propellants and primer cap; which includes an explosive, oxidizer, fuel, lubricants, stabilizers and other additives. An approach to the identification of particles characteristic of or consistent with GSR is to compare the elemental profile of the recovered particulate with that collected from case-specific known source items, such as the recovered weapon, Cartridge cases or victim-related items whenever necessary. This approach was called ‘‘case by case’’ by Romolo and Margot in an article published in 2001. In 2010 Dalby et al. published the latest review on the subject and concluded that the adoption of a "case by case" approach to GSR analysis must be seen as preferable, in agreement with Romolo and Margot. In light of similar particles produced from extraneous sources, both Mosher et al. (1998) Grima et al. (2012) presented evidence of pyrotechnic particles that can be mistakenly identified as GSR. Both publications highlight that certain markers of exclusion and reference to the general population of collected particulate can help the expert in designating GSR-similar particles as firework-sourced.
fixative Any chemical compound or solution that causes the fixation of cells, tissues, or other microscopic structures by any mechanism, thus preserving them for long-term, detailed study by methods such as embedding, staining, and microscopy. Common fixatives include dilute solutions of ethanol, acetic acid, formaldehyde, and osmium tetroxide, among others.
The result was twelve protein-like amino acids: aspartic acid, glutamic acid, glycine, alanine, valine, leucine, isoleucine, serine, threonine, proline, tyrosine, and phenylalanine. Many other similar experiments were carried out by teams of scientists such as Heyns and Pavel, Oro and Kamat, and Fox and Windsor that led to the production of amino acids.
In physics, a fluid is a liquid, gas, or other material that may continuously move and deform (flow) under an applied shear stress, or external force. They have zero shear modulus, or, in simpler terms, are substances which cannot resist any shear force applied to them.
Sources: en.wikipedia.org
A DALY (Disability-Adjusted Life Year) is a measure that reflects the total burden of disease. It combines years of life lost (due to premature death) and years lived with disability (adjusted for the severity of the disability). The lower the DALY rates, the lower the burden of endocrine disorders in a country. The map shows that large parts of Asia have lower DALY rates (pale yellow), suggesting that endocrine disorders have a relatively low impact on overall health, whereas some countries in South America and Africa (specifically Suriname and Somalia) have higher DALY rates (dark orange to red), indicating a higher disease burden from endocrine disorders.
==== Acetaminophen ==== One of the main types of drug studies conducted is using astronauts as test subjects and measuring drug dynamics before and after spacecraft flight. A study on acetaminophen pharmacokinetics was performed on ten astronauts, studying its concentration dynamics in saliva two months before spaceflight and during long-term spaceflight. Saliva samples were analyzed at intervals of 0.017, 0.33, 0.5, 0.75, 1, 2, 4, and 6 hours after acetaminophen intake by HPLC with UV spectrophotometric detection at 254 nm. The absorption of acetaminophen during spaceflight was delayed after tablet administration and the bioavailability of the encapsulated drug was found to be moderately decreased. Additionally, the half-life of encapsulated acetaminophen was prolonged during spaceflight.
=== NMR spectroscopy === Hydrogen and deuterium nuclei are grossly different in their magnetic properties. Thus it is possible to distinguish between them by NMR spectroscopy. Deuterons will not be observed in a 1H NMR spectrum and conversely, protons will not be observed in a 2H NMR spectrum. Where small signals are observed in a 1H NMR spectrum of a highly deuterated sample, these are referred to as residual signals. They can be used to calculate the level of deuteration in a molecule. Analogous signals are not observed in 2H NMR spectra because of the low sensitivity of this technique compared to the 1H analysis. Deuterons typically exhibit very similar chemical shifts to their analogous protons. Analysis via 13C NMR spectroscopy is also possible: the different spin values of hydrogen (1/2) and deuterium (1) gives rise to different splitting multiplicities. NMR spectroscopy can be used to determine site-specific deuteration of molecules. Another method uses HSQC spectra. Typically HSQC spectra are recorded at a series of timepoints while the hydrogen is exchanging with the deuterium. Since the HSQC experiment is specific for hydrogen, the signal will decay exponentially as the hydrogen exchanges. It is then possible to fit an exponential function to the data, and obtain the exchange constant. This method gives residue-specific information for all the residues in the protein simultaneously The major drawback is that it requires a prior assignment of the spectrum for the protein in question.
Selenium disulfide has a composition that approximates to SeS2 and is sometimes called selenium sulfide. However, as used in proprietary formulations, it is not a pure chemical compound but a mixture of eight-membered-ring compounds where the overall Se:S ratio is 1:2. The specific chemicals contain a variable number of S and Se atoms, SenS8−n. Many selenium sulfides are known, as indicated by 77Se-NMR spectroscopy.
Binge eating disorder (BED) is an eating disorder characterized by frequent and recurrent binge eating episodes with associated psychological and social dysfunction, but without the compensatory behaviors common to bulimia nervosa, OSFED, or the binge–purge subtype of anorexia nervosa. BED is a recently identified condition, distinguished nosologically to separate the binge eating that defines it from the binge eating seen in bulimia nervosa, which involves post-binge purging. Individuals diagnosed with bulimia nervosa or binge eating disorder show similar patterns of compulsive overeating, neurobiological features such as impaired cognitive control and food addiction, as well as biological and environmental risk factors. Some professionals consider BED to be a milder form of bulimia, with the two conditions on the same spectrum. Binge eating is one of the most prevalent eating disorders among adults, though it receives less media coverage and research attention than anorexia nervosa and bulimia nervosa.
Sources: en.wikipedia.org
== Additional reading == Zelzer, M. (2015), "Peptide-based switchable and responsive surfaces", Switchable and Responsive Surfaces and Materials for Biomedical Applications, Elsevier, pp. 65–92, doi:10.1016/b978-0-85709-713-2.00003-1, ISBN 978-0-85709-713-2, retrieved 2023-04-30 Schwartz, Jeffrey; Avaltroni, Michael J; Danahy, Michael P; Silverman, Brett M; Hanson, Eric L; Schwarzbauer, Jean E; Midwood, Kim S; Gawalt, Ellen S (2003). "Cell Attachment and Spreading on Metal Implant Materials". Materials Science and Engineering: C. 23 (3): 395–400. doi:10.1016/S0928-4931(02)00310-7.
The ones who gained some wealth, reinvested into the economy around the Costa del Sol region in southern Spain. The Riffian diaspora has thus spread its economic system throughout Europe. During the 1960s, Belgium and the Netherlands, unlike other countries in Western Europe, had no North African colonial past, welcomed massive Moroccan immigration from northern Morocco to work in the mines, iron and steel industry in Wallonia. Afterward, this process continued in Flanders, and the Netherlands, in the midst of an economic boom. The drug trade eventually followed these communities in exile, from Morocco to the Netherlands, through Spain, France, and Belgium. During the 1980s, De Pijp and Bos en Lommer districts located in Amsterdam, housed the most Moroccan immigrants. During this period, many Dutch-Moroccans saw this as an opportunity to export hashish from the Ketama mountains in Morocco to the Netherlands, often aboard their old vehicles such as Mercedes-Benz S-Class cars. It was around this time in the mid-1980s that the modern mafia structures started to evolve. The traffickers were used to crossing borders, carrying weapons, and they were known in Morocco to be very violent. The Moroccan state has abandoned and neglected the Rif region for many years by refusing to invest in the infrastructure, which has prompted most Moroccans from cities like Al Hoceïma and Nador to devote themselves entirely to the production of Hashish. In the 1980s, cocaine gained a lot of popularity.
=== Primary reference materials === Primary reference materials define the scales on which isotopic ratios are reported. This can mean a material that historically defined an isotopic scale, such as Vienna Standard Mean Ocean Water (VSMOW) for hydrogen isotopes, even if that material is not currently in use. Alternatively, it can mean a material that only ever existed theoretically but is used to define an isotopic scale, such as VCDT for sulfur isotope ratios.
==== Chirality ==== The two different chiralities of omeprazole are both metabolized into inactive products by cytochrome P450 enzymes, but each chirality is differently inactivated by specific isozymes. Compared to the (R)-enantiomer, the (S)-enantiomer is relatively more resistant to metabolism, especially metabolism by CYP2C19 (if it's processed by CYP2C19 at all). As a result, among people with a more active version of CYP2C19 ("extensive metabolizers"), the (R) half of a dose of omeprazole is likely to perform more poorly. Conversely, among those with a less active version of CYP2C19 ("poor metabolizers"), more the (R) half is expected to survive metabolism and end up useful. The proportion of the poor metabolizer phenotype varies widely between populations, from 2.0 to 2.5% in African Americans and white Americans to >20% in Asians. Several pharmacogenomics studies have suggested that PPI treatment should be tailored according to CYP2C19 metabolism status. AstraZeneca also developed esomeprazole (Nexium) which is a eutomer, purely the (S)-enantiomer, rather than a racemate like omeprazole.
Sources: en.wikipedia.org
Reports describe modulation of GABA signalling, changes in monoamine turnover and effects on neurotrophic factor expression. These observations come mainly from animal and cell studies. A single unifying mechanism has not been demonstrated.
The peptide enters plasma rapidly and is broken down by ordinary proteases into amino acids and shorter fragments. Reported half-lives are short. Whether meaningful amounts of the intact molecule reach the brain is an open question.
Most clinical reports are small, published in Russian and not independently replicated. English-language reviews highlight the absence of large randomised trials. Conclusions about efficacy should be treated as provisional.
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.