Semax and Selank: Two peptides with an unusual history in Russian neuroscience

Online nootropic culture often pairs these two with coffee and focus talk. The chemistry is older and stranger. Semax is Met-Glu-His-Phe-Pro-Gly-Pro, an ACTH(4–10) analog with a Pro-Gly-Pro tail so it lasts longer than a minute. Selank is a tuftsin analog with the same stabilizer. Both came out of the Institute of Molecular Genetics in Moscow. Both have Russian registered-product histories. Neither has an FDA indication for studying at a desk.

Semax and the BDNF graph

Dolotov and colleagues, in 2006, gave rats one intranasal dose and watched the hippocampus. BDNF protein rose about 1.4-fold. TrkB phosphorylation rose about 1.6-fold. Exon-III BDNF messenger RNA rose threefold. The animals completed more conditioned avoidance. That is a mechanism paper with a learning endpoint in a rodent. The thickest human file is ischemic stroke in Russian hospitals. Gusev’s 2018 series reported higher plasma BDNF and better Barthel scores when Semax was added to rehabilitation. Stroke recovery is a different clinical question from everyday “focus.” A foreign marketing authorization is also distinct from an FDA approval.

Selank compared with a benzodiazepine

Zozulia and colleagues compared Selank with medazepam in 62 patients with generalized anxiety disorder and neurasthenia. Anxiolytic effects on Hamilton, Zung, and CGI were similar. Selank also showed antiasthenic and psychostimulant effects the benzodiazepine did not. Blood leu-enkephalin half-life, which had been short in these patients, lengthened on Selank. That is a real, small, Russian-language comparative trial — worth reading on those terms, and still a different object from a Western, placebo-controlled Phase III for a research vial.

BDNF changes in a rat hippocampus are a finding with a clear experimental frame — and a useful place to keep the conversation.