Everything below concerns Semax. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Last reviewed on 2026-01-29. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
Reverse-phase high-performance liquid chromatography with ultraviolet detection near 214 nanometres is the standard purity method. Mass spectrometry, typically electrospray ionisation, confirms identity through the expected mass-to-charge pattern. Amino acid analysis can verify composition independently. Chiral purity requires separate techniques such as derivatisation followed by chromatographic separation, and such data are rarely reported for research-grade material.
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.
| 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 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.
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.
Purity assessment relies mainly on reverse-phase high-performance liquid chromatography with ultraviolet detection. Because the peptide lacks a strong chromophore, detection often uses backbone absorbance near 214 nm. Identity is confirmed by mass spectrometry, typically electrospray ionization or matrix-assisted laser desorption, comparing the measured mass against the expected value. Amino acid analysis can verify composition after acid hydrolysis. Diastereomer content and residual counterions are reported less often, although both can influence biological assays.
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.
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The condition can cause localized pain, discoloration (paleness), and sensations of cold and/or numbness. When exposed to cold temperatures, the blood supply to the fingers or toes, and in some cases the nose or earlobes, is markedly reduced; the skin turns pale or white (called pallor) and becomes cold and numb. These events are episodic, and when the episode subsides or the area is warmed, the blood flow returns and the skin color first turns red (rubor), and then back to normal, often accompanied by swelling, tingling, and a painful "pins and needles" sensation. All three color changes are observed in classic Raynaud's yet not all patients see all of the aforementioned color changes in all episodes, especially in milder cases of the condition. The red flush is due to reactive hyperemia of the areas deprived of blood flow. In pregnancy, this sign normally disappears due to increased surface blood flow. Raynaud's has occurred in breastfeeding mothers, causing nipples to turn white and painful.
Although the closest counterions partially mask a charged micelle (by up to 92%), the effects of micelle charge affect the structure of the surrounding solvent at appreciable distances from the micelle. Ionic micelles influence many properties of the mixture, including its electrical conductivity. Adding salts to a colloid containing micelles can decrease the strength of electrostatic interactions and lead to the formation of larger ionic micelles. This is more accurately seen from the point of view of an effective charge in hydration of the system.
Xi has called China–United States relations in the contemporary world a "new type of great-power relations", a phrase the Obama administration had been reluctant to embrace. Xi has indirectly spoken out critically on the U.S. "strategic pivot" to Asia. Relations with the U.S. soured after Donald Trump became president in 2017. Since 2018, U.S. and China have been engaged in an escalating trade war. In 2020, the relations further deteriorated due to the COVID-19 pandemic.
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Sources: en.wikipedia.org
=== Damage === Over 40% of French grape vines and vineyards were devastated over a 15-year period from the late 1850s to the mid-1870s. The French economy was badly hit by the blight: many businesses were lost, and wages in the wine industry were cut to less than half. There was also a noticeable trend of migration to places such as Algiers and America. The production of cheap raisins and sugar wines caused the domestic industry several problems that threatened to persist even after the blight itself. The damage to the French economy is estimated to have been slightly over 10 million Francs.
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==== Additional modifications ==== In addition to phosphorylation and ubiquitination, proteins may be subjected to (among others) methylation, acetylation, glycosylation, oxidation, and nitrosylation. Some proteins undergo all these modifications, often in time-dependent combinations. This illustrates the potential complexity of studying protein structure and function.
In 1996, the World Health Organization (WHO) launched the EMF (ElectroMagnetic Fields) Project to bring together current knowledge and available resources from key international and national organizations and scientific institutions on electromagnetic fields. The German Federal Office for Radiation Protection (BfS) published the following recommendation in 2006:
Then in 1976, a student gave me a book by A.E. Wilder-Smith, The Creation of Life: A Cybernetic Approach to Evolution. Many pages of that book deal with arguments against Biochemical Predestination, and I found myself hard-pressed to come up with a counter-rebuttal. Eventually, several other books and articles by neo-creationists came to my attention. I read some of Henry Morris' books, in particular, The Genesis Flood. I'm not a geologist, and I don't agree with everything in that book, but what stood out was that here was a scientific statement giving a very different view of earth history. Though the book doesn't deal with the subject of the origin of life per se, it had the effect of suggesting that it is possible to have a rational alternative explanation of the past. In 1980, the San Francisco State University Department of Biology had a dispute over Kenyon's presentation of creationism, then called "scientific creationism" in Biology module 337 Evolution. At that time, Kenyon challenged anyone on the faculty to a debate on the merits of evolutionary theory versus "scientific creationism." According to SFSU biology professor John Hafernik, "There was much discussion in faculty meetings as well. Eventually the faculty voted (none opposed, seven abstentions) not to alter the description of Biology 337 to include creationism. The precedent set, in the context of the 1980 discussions, was that the Department did not support teaching creationism."
Sources: en.wikipedia.org
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As such, it has been said that ibogaine does not appear to be acting primarily or exclusively as a serotonergic psychedelic and that its hallucinogenic effects cannot be ascribed to serotonin 5-HT2A receptor activation. In any case, ibogaine has still been found to have significant in-vivo occupancy of the serotonin 5-HT2A receptor, suggesting that it is still a ligand of the receptor. Ibogaine has been investigated as a potential treatment for substance use disorders, with proposed mechanisms including inhibition of α3β4 nicotinic acetylcholine receptors. The β-carbolines or harmala alkaloids bear a close resemblance to ibogaine in terms of chemical structure and subjective effects. Relatedly, harmaline and 6-methoxyharmalan fully substitute for ibogaine in drug discrimination tests, whereas harmine, harmane, harmalol, and tryptoline partially substitute for ibogaine. As with the case of ibogaine, the psychedelic DOM partially substitutes for harmaline and this further supports a role of serotonin 5-HT2A receptor activation in the effects of ibogaine as well as of harmala alkaloids. However, like ibogaine, harmala alkaloids like harmaline bound to the serotonin 5-HT2A receptor but were inactive as direct agonists of the receptor even at very high concentrations in vitro. In addition, whereas ibogaine and noribogaine bind to κ-opioid receptors, harmala alkaloids like harmine and harmaline show no affinity for these receptors.
=== Legal status === It was approved in both the European Union (brand name Revestive) and the United States (brand name Gattex) in 2012. It was granted orphan drug designation by the European Medicines Agency (EMA).
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.
Dry powder is best kept sealed, protected from light, and held at minus 20 degrees Celsius or below. Desiccant packaging helps limit moisture uptake because the material is hygroscopic. A sealed vial should be allowed to equilibrate to room temperature before opening to reduce condensation.