What Semax is

Semax is a synthetic peptide derived from ACTH(4-10), a seven amino acid fragment of adrenocorticotropic hormone, with a Pro-Gly-Pro tail added at the C terminus. The fragment was chosen because it retains the neurological activity of the parent hormone while carrying none of its corticotropic effect, so it does not stimulate cortisol production the way ACTH does. The added tripeptide tail exists to resist enzymatic breakdown, which the bare fragment does not survive well. Developed in Russia from the 1980s, it remains largely absent from Western clinical literature, and most published work on it is Russian language.

How Semax compares

Against Selank: the two are almost always discussed together and are usually described as opposites, Semax as the stimulating half of the pair and Selank as the calming one. They derive from entirely different parent molecules, Semax from ACTH and Selank from tuftsin, and share only their country of origin and the Pro-Gly-Pro stabilising tail. Against the racetams: Semax is a peptide and not orally stable, which is the practical difference.