The Semax/Selank combination consists of two synthetic heptapeptides: Semax (Met-Glu-His-Phe-Pro-Gly-Pro), an analog of the ACTH(4–10) fragment, and Selank (Thr-Lys-Pro-Arg-Pro-Gly-Pro), an analog of the immunomodulatory tetrapeptide tuftsin. Both sequences terminate in a Pro-Gly-Pro motif that increases resistance to circulating peptidases relative to the parent fragments. In dissociated neuronal cultures, organotypic slices, and intact rodent models, Semax administration is associated with altered transcription and translation of brain-derived neurotrophic factor and TrkB, shifts in striatal and hippocampal monoamine turnover, and changes in measures of synaptic-protein expression and long-term potentiation. Selank produces quantifiable alterations in GABAergic transmission, endogenous enkephalin levels, and selected cytokine-related transcripts, together with modified behavior on elevated-plus-maze and other conflict assays. Concurrent administration of the two peptides therefore permits simultaneous recording of overlapping and distinct experimental endpoints, including monoaminergic and GABAergic neurochemistry, neurotrophin expression, synaptic-marker density, and performance metrics on hippocampus-dependent spatial or inhibitory-avoidance tasks as well as anxiety-related behavioral tests, under standardized preclinical conditions.