Research Overview
A shared design, two mechanisms
Semax and Selank come from the same school of Russian peptide chemistry and share one structural trick: a short bioactive fragment — ACTH(4–10) in one case, tuftsin in the other — extended with Pro-Gly-Pro at the C-terminus so that exopeptidases cannot strip it in minutes. That shared chemistry is what makes them formulate well together. Their biology, however, diverges, which is the actual reason they are paired.
The Semax component
Rodent studies have reported increased BDNF and NGF expression in hippocampus and cortex, altered TrkB receptor signalling and shifts in dopaminergic and serotonergic turnover. Behavioural work has looked at attention, learning acquisition and memory retention, and ischaemia models have used neuronal-survival endpoints. This is the neurotrophic and plasticity axis of the pair.
The Selank component
- Anxiolytic-type behaviour in elevated plus maze and open field paradigms, reported without the sedation typical of benzodiazepine comparators.
- Modulation of GABA-A receptor subunit expression.
- Inhibition of enkephalin-degrading enzymes, prolonging endogenous enkephalin signalling.
- Changes in expression of inflammatory and stress-related genes, consistent with its tuftsin origin.
Intranasal delivery as the variable
The nasal epithelium is thin, well vascularised and adjacent to olfactory and trigeminal projections, so it has been examined as a route that bypasses first-pass hepatic metabolism. Reported transport efficiency varies considerably by molecular size, charge, formulation viscosity and droplet distribution. Because the two peptides here are similar in size (752 and 814 g/mol) and both water-soluble, they present a relatively matched pair for mucosal-transport comparisons.
