Selank is a synthetic heptapeptide derived from the endogenous immunomodulatory peptide tuftsin and was originally developed in Russia for its anxiolytic and nootropic properties, with research highlighting its unique ability to influence both neural and immune pathways. Its pharmacological profile is multifaceted, beginning with its role as a positive allosteric modulator of GABA receptors, where it enhances the actions of gamma-aminobutyric acid (GABA), the brain’s principal inhibitory neurotransmitter, thereby reducing neuronal excitability and promoting anxiolysis without the sedative or dependence-forming characteristics associated with traditional benzodiazepines. In addition to its GABAergic effects, Selank has been shown to modulate monoaminergic neurotransmission, influencing the synthesis, release, and turnover of serotonin, dopamine, and norepinephrine—neurochemical systems essential for emotional regulation, cognitive processing, sustained attention, and stress resilience. A further mechanism involves Selank’s ability to inhibit the enzymatic degradation of enkephalins, endogenous opioid peptides involved in pain modulation, reward signaling, and adaptive stress responses, thereby prolonging their bioactivity and contributing to mood stabilization. Together, these actions illustrate Selank’s broad neuropsychopharmacological impact and have generated significant interest in its potential applications across anxiety disorders, cognitive impairment, stress-related conditions, and neuroimmune dysregulation.