Selank

Selank is a synthetic heptapeptide analogue of tuftsin, an endogenous immunomodulatory peptide derived from the Fc region of immunoglobulin G. Developed at the Institute of Molecular Genetics in Russia, Selank has been studied extensively for its anxiolytic properties, GABA system modulation, and effects on immune function. The compound is often researched alongside Semax, where Semax investigations concentrate on cognitive enhancement and BDNF modulation, Selank research focuses on anxiety reduction, stress response regulation, and GABAergic neurotransmission. Selank has been approved in Russia as a pharmaceutical treatment for generalised anxiety disorder. Research has examined its influence on serotonin and norepinephrine metabolism, its modulation of interleukin expression, and its effects on enkephalin degradation. The peptide's dual anxiolytic and immunomodulatory profile represents a unique pharmacological combination not commonly found in single-molecule compounds. Studies have documented its effects on the hypothalamic-pituitary-adrenal (HPA) axis and its ability to stabilise enkephalins in blood serum, contributing to its anxiolytic mechanism of action.

Selank is built on the same design principle as Semax. It is the tuftsin sequence Thr-Lys-Pro-Arg extended with a C-terminal Pro-Gly-Pro tail, giving TKPRPGP, and as with Semax that PGP extension exists to blunt aminopeptidase degradation rather than to add activity of its own. The two compounds come from the same institute and share a structural strategy, which is why they are so often studied as a pair.

Two mechanisms dominate the published work. The first is GABAergic: research reports altered expression of genes encoding GABA-A receptor subunits in rat brain, which is the usual explanation offered for the anxiolytic profile. The second is enkephalinergic, Selank having been reported to inhibit the degradation of enkephalins in blood plasma and thereby prolong their action. Effects on interleukin expression and on serotonin and noradrenaline metabolism are described across the same literature, and the immunomodulatory activity traces back to tuftsin's own role as an immunostimulatory fragment of immunoglobulin G.

The same evidential caveat applies as to Semax, and for the same reason. The literature is predominantly Russian-language, concentrated in a small institutional cluster, and thinly replicated independently. Selank is registered in Russia for generalised anxiety disorder but holds no marketing authorisation in the UK, the EU or the US. Supplied as lyophilised powder for in-vitro laboratory research only.