Everything below concerns mass spectrometry. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Updated 2026-01-16. Numbers and descriptions here follow the published literature rather than marketing material.
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.
Reported activity for Selank centers on anxiolytic and nootropic effects. Russian clinical reports describe use in anxiety and in cognitive or attention-related complaints. Most of this evidence comes from studies conducted by the same research groups that developed the peptide. Independent replication in other countries remains limited, and no major Western regulatory agency has approved the compound for any indication. The gap between local reports and external verification is a recurring point in discussions of the peptide.
Tuftsin, the parent structure, is a naturally occurring immunomodulatory tetrapeptide released from the Fc region of immunoglobulin G by spleen enzymes. Selank extends this four-residue sequence with three additional amino acids. The stated rationale is that the added tail slows enzymatic breakdown and may influence receptor interactions. How the full heptapeptide behaves at the molecular level is not firmly established, and proposed mechanisms often involve indirect modulation of neurotransmitter or immune signaling rather than a single defined target.
| 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 |
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.
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.
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.
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.
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The extent to which psilocin (and by extension psilocybin) is metabolized by MAO, specifically MAO-A, is not fully clear, but has ranged from 4% to 33% in different studies based on metabolite excretion. However, circulating levels of the deaminated metabolite of psilocin are far higher than those of free unmetabolized psilocin with psilocybin administration. An early clinical study of psilocybin in combination with short-term tranylcypromine pretreatment found that tranylcypromine marginally potentiated the peripheral effects of psilocybin, including pressor effects and mydriasis, but overall did not significantly modify the psychoactive and hallucinogenic effects of the psilocybin, although some of its emotional effects were said to be reduced and some of its perceptual effects were said to be amplified. Some psychedelics are substrates of cytochrome P450 (CYP450) enzymes, for instance LSD being a substrate of CYP2D6 as well as of several other CYP450 enzymes. As such, CYP450 inhibitors may increase exposure to CYP450-substrate psychedelics such as LSD and thereby potentiate their effects as well as risks. A clinical study found that administration of LSD to people taking paroxetine, a selective serotonin reuptake inhibitor (SSRI) and strong CYP2D6 inhibitor, increased LSD exposure by about 1.5-fold. The combination was well-tolerated and did not modify the pleasant subjective effects or physiological effects of LSD, whereas negative effects of LSD, including "bad drug effect", anxiety, and nausea, were reduced.
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A laboratory experiment using animals to study the development and progression of diseases. Animal studies also test how safe and effective new treatments are before they are tested in people. (NCI) Applicable regulatory requirement
Sources: en.wikipedia.org
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=== Pre-release === On April 12, 2000, Valve Software announced a partnership with the Counter-Strike Team, confirming that Counter-Strike 1.0 would be included in an upcoming Half-Life patch. Though not explicitly stated, it is widely believed that this followed Valve's acquisition of Counter-Strike. Statements suggest the rights were sold in early 2000, involving a financial transaction. Despite the partnership, two more beta versions were released. Beta 6.5 (June 8, 2000) introduced an updated netcode, while Beta 7.0 (August 26, 2000) added drive-able vehicles. Following the acquisition of the game by Valve, while Cliffe continued working for them, Le did additional work towards a Counter-Strike 2.0 based on Valve's upcoming Source engine, but left to start his own studio after Valve opted to shelve the sequel. Valve planned to release Counter-Strike both as a Half-Life mod and a standalone retail product on August 31, 2000. The decision aimed to increase accessibility and test market demand for a multiplayer game independent of Half-Life. Legal issues arose before the retail release, particularly regarding weapon names, which were changed to fictional alternatives. Valve also had to secure rights for maps and textures, leading to modifications and removals of certain assets. Minh Le, one of the original developers, compensated mappers whose work Valve did not purchase.
=== Genes in other plants === CLE genes have been found in numerous monocots, dicots, and even moss. Research has even shown that some plants, like rice, contain the presence of a multi-CLE domain. Various CLE-like genes have also been found in the genomes of plant-parasitic nematodes such as beet, soybean and potato cyst nematodes.
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.
Selank is a synthetic peptide made of seven amino acids. It is modeled on tuftsin, a natural tetrapeptide, with an added three-residue tail. It is not a small-molecule drug.