Selank is a synthetic heptapeptide with anxiolytic (anti-anxiety), nootropic and immunomodulatory activity. It was created at the Institute of Molecular Genetics of the Russian Academy of Sciences together with the V. V. Zakusov Research Institute of Pharmacology as a stabilized analog of the endogenous tetrapeptide tuftsin. Unlike classic benzodiazepines, selank did not cause pronounced sedation, muscle relaxation or dependence in studies, which made it the subject of prolonged preclinical and clinical investigation.
The molecule is a peptide regulator with a short plasma half-life: a tripeptide "tail" Pro-Gly-Pro is added to native tuftsin, which slows enzymatic breakdown and prolongs the biological action. Below is a brief account of the compound's class, its mechanism and the main lines of research.
What it is and its class
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro (TKPRPGP). It is a derivative of tuftsin (Thr-Lys-Pro-Arg), a natural immunomodulatory fragment of the heavy chain of immunoglobulin G. Adding the C-terminal Pro-Gly-Pro fragment increases resistance to peptidases compared with the parent tetrapeptide. By pharmacological profile the compound is classed among peptide anxiolytics/nootropics. Empirical formula: C₃₃H₅₇N₁₁O₉, molar mass: about 751.9 g/mol, CAS (Chemical Abstracts Service) registry number: 129954-34-3.
Mechanism of action
Selank's mechanism is multi-target and differs from the benzodiazepine one: the compound is not a direct agonist of the GABA-A receptor but rather influences the regulation of neurotransmitter systems. One documented effect is inhibition of blood-serum enzymes that cleave enkephalins, which prolongs the action of endogenous enkephalins [1]. Intranasal administration of selank has also been shown to regulate expression of the neurotrophic factor BDNF in the rat hippocampus [2], while the peptide itself modulates monoamine turnover, in particular the serotonin system. Thanks to its kinship with tuftsin, selank also carries an immunomodulatory component: an effect on cytokine balance. This multi-component nature, according to available data, explains the combination of anti-anxiety and cognitive activity in experimental models.
What the research shows
The clinical direction focuses primarily on generalized anxiety disorder (GAD) and neurasthenia. In work on GAD therapy a heterogeneous response is described: some patients responded quickly (in the first days), some responded gradually over roughly two weeks, with tolerability rated as good and without the sedation typical of benzodiazepines [4]. Preclinical studies cover neurotrophic and cognitive effects: in rats selank attenuated ethanol-induced memory impairment while changing BDNF content in the hippocampus and prefrontal cortex [3]. Separate experimental directions concern attenuation of morphine withdrawal signs and effects on stress reactivity. Overall the evidence base was built mainly by Russian research groups, often on small samples and short observation periods, so the results are best read as directions that need independent replication.
Form and handling (research-use)
Longeva supplies selank as a research substance (reagent) with an accompanying certificate of analysis (COA); it is a material for laboratory research, not a medicine. The typical supply form is a lyophilized powder, kept cold, protected from light and moisture and reconstituted in a suitable solvent immediately before the experiment. Because of its peptide nature the compound is sensitive to repeated freeze-thaw, so the reconstituted solution is usually aliquoted. Working with the substance implies good laboratory practice, personal protective equipment and correct documentation of the batch by CAS number and certificate of analysis.