What are the main differences between nootropic peptides like Semax, Selank, and Dihexa?

Semax primarily enhances cognitive function by modulating BDNF and dopamine systems, improving focus, memory, and learning. Selank works through GABA and serotonin pathways, offering anxiolytic effects without sedation while supporting mental clarity. Dihexa is a potent synaptogenesis enhancer that promotes new neural connections, potentially benefiting age-related cognitive decline. While Semax and Selank are approved pharmaceuticals in Russia, none of these peptides are FDA-approved in the United States.