Semax and Cognitive Enhancement: What Has Been Studied

What the research covers

A PubMed search found no indexed trial report of Semax for memory or attention in healthy adults. The human studies found include small Russian stroke studies and one brain scan study.

Semax is a man-made peptide of seven amino acids. It is based on a short piece of the hormone ACTH, called ACTH(4-10). In a 1997 study, 30 patients with a recent stroke got Semax with standard care. They were compared with 80 patients on standard care alone. The authors reported some effect on the speed of recovery, mainly of movement. The most effective daily doses were 12 mg for medium-severity strokes and 18 mg for severe strokes. Treatment courses lasted 5 and 10 days.

A later study followed 110 patients after stroke, with and without Semax. Semax was given at 6000 micrograms a day in two 10-day courses, 20 days apart. It raised blood BDNF, and the authors linked it to better scores for daily living. These studies measured stroke recovery, not memory in healthy people. In a 2018 brain scan study, 14 healthy people got 1% Semax in the nose and 10 got a placebo. Scans showed a larger volume in part of a resting brain network. No memory or attention test was reported.

In a rodent (rat) study, one dose of 50 micrograms per kg raised BDNF protein in the hippocampus 1.4-fold. The treated rodent (rat) group also showed more learned avoidance responses. Another rodent (rat) study found BDNF and NGF gene activity rose or fell, depending on the brain area.

Sources

1. Gusev EI, Skvortsova VI, Miasoedov NF, et al. Effectiveness of semax in acute period of hemispheric ischemic stroke (a clinical and electrophysiological study) Zh Nevrol Psikhiatr Im S S Korsakova (1997). PMID 11517472 Russian study, 30 patients with acute ischaemic stroke given Semax, compared with 80 on standard care; daily doses 12 and 18 mg.
2. Gusev EI, Martynov MY, Kostenko EV, et al. The efficacy of semax in the tretament of patients at different stages of ischemic stroke Zh Nevrol Psikhiatr Im S S Korsakova (2018). PMID 29798983 doi:10.17116/jnevro20181183261-68 Russian study, 110 patients after ischaemic stroke; 6000 micrograms a day in two 10-day courses; blood BDNF and Barthel index.
3. Lebedeva IS, Panikratova YR, Sokolov OY, et al. Effects of Semax on the Default Mode Network of the Brain Bull Exp Biol Med (2018). PMID 30225715 doi:10.1007/s10517-018-4234-3 Brain scan (fMRI) study, 24 healthy volunteers, nasal 1% Semax (14) or placebo (10); no memory test reported.
4. Dolotov OV, Karpenko EA, Inozemtseva LS, et al. Semax, an analog of ACTH(4-10) with cognitive effects, regulates BDNF and trkB expression in the rat hippocampus Brain Res (2006). PMID 16996037 doi:10.1016/j.brainres.2006.07.108 Rodent (rat) study: one 50 micrograms/kg dose raised hippocampal BDNF protein 1.4-fold.
5. Shadrina M, Kolomin T, Agapova T, et al. Comparison of the temporary dynamics of NGF and BDNF gene expression in rat hippocampus, frontal cortex, and retina under Semax action J Mol Neurosci (2010). PMID 19662538 doi:10.1007/s12031-009-9270-z Rodent (rat) study: Semax changed NGF and BDNF gene activity in different directions by brain region.