Semax is a synthetic heptapeptide derived from the ACTH(4-7) sequence — the minimal active fragment responsible for ACTH’s nootropic effects — with a C-terminal Pro-Gly-Pro extension that significantly improves metabolic stability. It was originally developed in Russia and has been studied extensively for cognitive enhancement, neuroprotection, and neuroplasticity. A primary mechanism of interest is Semax’s ability to rapidly upregulate BDNF and NGF in the hippocampus and frontal cortex, supporting synaptogenesis and neuronal survival. Research has also examined its potential in models of stroke recovery, ADHD-like cognitive deficits, and chronic stress.