Semax is a synthetic heptapeptide — a chain of seven amino acids — with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. It was first described in the late 1980s. Structurally, Semax is derived from a fragment of adrenocorticotropic hormone (ACTH), specifically the 4-10 segment, with an added Pro-Gly-Pro tripeptide tail that increases resistance to enzymatic degradation compared to the unmodified ACTH fragment.

The compound has a molecular formula of C₃₇H₅₁N₉O₁₀S (free acid form) and a molar mass of approximately 813.93 g/mol (826.92 g/mol as the acetate salt commonly supplied). It is water-soluble and supplied as a white to off-white lyophilized powder. Its CAS registry number is 80714-61-0. The Pro-Gly-Pro extension is a known structural motif used in peptide chemistry to resist cleavage by prolyl endopeptidases, distinguishing it structurally from the native ACTH(4-10) fragment.

This product is strictly for research purposes only. Not approved for human or animal use.

PubChem Reference: View compound profile on NIH PubChem