Selank is a synthetic heptapeptide (Thr-Lys-Pro-Arg-Pro-Gly-Pro) derived from the endogenous immune-modulating peptide tuftsin, developed at the same Russian Academy of Sciences institute as Semax. The base tuftsin sequence (Thr-Lys-Pro-Arg) was extended with a Pro-Gly-Pro tripeptide tail that stabilizes the molecule against enzymatic degradation and enhances its anxiolytic properties. Like Semax, Selank has regulatory approval in Russia as a pharmaceutical compound — classified as an anxiolytic nootropic with immunomodulatory properties.

Selank modulates GABAergic neurotransmission by allosterically enhancing GABA-A receptor function — similar in mechanism (though not in structure) to benzodiazepines, but without the receptor desensitization, sedation, or cognitive impairment that characterize benzodiazepine pharmacology. Selank also increases BDNF expression (though less potently than Semax), stabilizes enkephalin degradation to prolong endogenous opioid tone, and modulates serotonin metabolism by influencing tryptophan hydroxylase activity. Its immunomodulatory effects stem from the tuftsin backbone: enhanced monocyte and natural killer cell function, modulation of cytokine balance, and stabilization of IL-6 signaling.

The research literature positions Selank as the anxiolytic counterpart to Semax's cognitive-enhancement focus. Studies document significant reductions in anxiety metrics without sedation, cognitive dulling, motor impairment, or tolerance development. Memory and attention improvements are documented but are generally attributed to anxiety reduction removing the cognitive interference of excessive worry rather than direct nootropic stimulation. The immunomodulatory research is compelling: studies show enhanced antiviral defense and immune cell activation, making Selank unique as a compound that addresses both psychological stress and immune resilience.

Selank is suited for researchers investigating anxiety modulation, stress resilience, immune-neuro interaction, and cognitive function under stress conditions. It pairs naturally with Semax — the "Semax/Selank stack" combines direct nootropic stimulation (Semax) with anxiolytic cognitive optimization (Selank) for a comprehensive cognitive protocol.

Reconstitute with 1ml bacteriostatic water (yielding 5mg/ml). Administer intranasally, typically 200-400mcg per dose, 2-3 times daily. Intranasal delivery provides the most rapid onset of anxiolytic effects (within 5-15 minutes). Subcutaneous injection is an alternative route. Selank has a short half-life of approximately 1-3 minutes in plasma, but its GABAergic and neurotrophin effects persist for several hours post-administration. Store at 2-8C after reconstitution. No tolerance, dependence, or withdrawal effects have been documented in the published literature.