Selank is built from tuftsin, a tetrapeptide fragment of the immunoglobulin G heavy chain with documented immunomodulatory activity. The same C-terminal Pro-Gly-Pro extension used in Semax is applied here, producing the heptapeptide TKPRPGP. The extension is a stability modification rather than a functional one, and it is why the compound is workable in laboratory conditions where native tuftsin is not.

Two pathways account for most of the published work. The first is GABAergic: preclinical studies examine expression of GABA-A receptor subunits in hippocampal and cortical tissue following administration, treating the compound as a modulator of receptor expression rather than a direct receptor ligand. The second is enkephalinergic, where the research question is inhibition of enkephalin-degrading enzymes and the consequent extension of endogenous enkephalin half-life in plasma and tissue.

Its tuftsin lineage also places it in neuroimmune research. Studies examine interleukin-6 and interferon-gamma expression alongside the central signalling measures, which is unusual: the compound is one of a small number used to probe where immune signalling and neurotransmitter regulation intersect in the same model. Behavioural work in animal subjects covers stress-reactivity and anxiety-like paradigms. No therapeutic, diagnostic, or clinical conclusion is drawn from any study referenced above, and none should be inferred.