Semax is a synthetic heptapeptide, Met-Glu-His-Phe-Pro-Gly-Pro, in which the adrenocorticotropin fragment ACTH(4-7) (Met-Glu-His-Phe) is extended at the C-terminus by the tripeptide Pro-Gly-Pro. All residues are natural L-amino acids. Because it stops at Phe, it lacks the Arg-Trp pair of the ACTH(4-10) melanocortin core; the proline-rich extension was introduced to slow cleavage of the fragment, and the compound is often described in the literature as an ACTH(4-10) analog.

Reported molecular work includes specific, saturable binding of radiolabelled Semax to plasma membrane preparations from rat forebrain regions, concurrent biodegradation of the ligand in those preparations, and reported changes in brain-derived neurotrophic factor and TrkB expression in neural tissue. No defined melanocortin receptor subtype has been assigned to it.

Cited in neuropeptide binding and radioligand studies, peptidase biochemistry, neurotrophin expression in neuronal and brain-tissue models, and gene-expression profiling. Supplied as a lyophilized solid.

Research use only. This material is sold for in-vitro laboratory research and development purposes exclusively. It is not a drug, food, or dietary supplement, has not been evaluated by the FDA, and must not be used in humans or animals.