Semax is a synthetic peptide originally developed in Russia, derived from a fragment of ACTH (adrenocorticotropic hormone). Unlike the full hormone, Semax does not significantly affect cortisol levels—instead, it was specifically designed to target the brain and central nervous system for cognitive enhancement, mental performance, and neuroprotective support.

Semax is commonly classified as both a nootropic (cognitive enhancer) and a neuroprotective peptide due to its potential ability to support memory, focus, learning capacity, and overall brain function. It works by influencing important neurological pathways involved in dopamine signaling, brain-derived neurotrophic factor (BDNF), and cerebral blood flow, which may contribute to improved concentration, mental clarity, and resilience to stress.