Cerebrolysin is a peptide mixture with human RCT data for stroke and Alzheimer's. Semax is a registered Russian medicine for the same indications. Together they provide complementary neurotrophin support from two distinct mechanisms — one endogenous, one synthetic analog.
Semax drives focus and BDNF. Selank removes the anxiety that focus-enhancement often brings. Together they hit the same goal from opposite directions — and the mechanisms don't overlap.
PE-22-28 is a synthetic analog of spadin that blocks TREK-1 potassium channels — a novel antidepressant mechanism completely distinct from SSRIs, SNRIs, or any approved psychiatric drug. The animal data is promising. The human data does not exist.
Dihexa is reported to be seven orders of magnitude more potent than BDNF itself at promoting synaptogenesis in cell culture. It also has essentially no human data. That tension — extraordinary in vitro potency, near-zero clinical evidence — defines everything you need to know about where to place it.
Cerebrolysin is the only compound in this review series with multiple Cochrane reviews and regulatory approval in Europe and Asia. It is a peptide mixture, not a defined molecule — which makes it harder to characterise and harder to source reliably.
Selank is an anxiolytic peptide with Russian clinical approval for anxiety and asthenic disorders. It reduces anxiety without sedation and without dependence — a profile that distinguishes it from every pharmaceutical anxiolytic on the market.