N-acetyl Semax is a synthetic heptapeptide derived from the adrenocorticotropic hormone (ACTH) fragment ACTH(4-7), modified with an N-terminal acetyl group and a C-terminal Pro-Gly-Pro extension. This structural adaptation enhances its stability against enzymatic degradation. N-acetyl Semax interacts with melanocortin receptors (MC₄ and MC₅), modulating pathways linked to cognitive function, stress response, and neuroprotection.