Semax

Semax is a synthetic heptapeptide (Met-Glu-His-Phe-Pro-Gly-Pro) derived from the ACTH(4-10) sequence but with the C-terminal extension -Pro-Gly-Pro (PGP) that significantly extends its metabolic stability and biological activity compared to the parent ACTH fragment. It was developed at the Institute of Molecular Genetics of the Russian Academy of Sciences in the late Soviet period and has been used as a prescription nootropic in Russia since 1999 under the brand name Semax.

The most extensively documented biological effect of Semax in preclinical literature is stimulation of BDNF (brain-derived neurotrophic factor) and NGF (nerve growth factor) expression in the rat brain. Studies using both systemic and intranasal administration have shown significant increases in BDNF mRNA and protein in the hippocampus and frontal cortex following Semax treatment. These findings have directed research interest toward Semax as a tool for studying neurotrophin-dependent plasticity, memory consolidation, and neuroprotection.

Research in rodent models has also documented cognitive effects of Semax, with studies reporting improved performance on maze-learning tasks, enhanced memory consolidation, and increased attention. Mechanism-focused studies have implicated dopaminergic and serotonergic system modulation in addition to the neurotrophin effects. In stroke models, Semax has been investigated for its ability to reduce infarct volume and improve neurological outcomes when administered within a therapeutic window.

Semax is available for research purposes only and has not been approved by the FDA for any therapeutic application. Investigators in neuroscience research will find particular value in Semax's BDNF-stimulating properties and its well-documented behavioral pharmacology literature.