Dihexa

Dihexa is a compound derived from angiotensin IV (a fragment of the blood-pressure hormone system) but repurposed for the brain.

Its proposed mechanism is to amplify hepatocyte growth factor (HGF) and its receptor c-Met, a pathway involved in forming new connections between neurons. In animal memory models it's been reported to powerfully promote synapse formation, which is the source of its 'super-nootropic' reputation.

That reputation rests entirely on preclinical work — there's no human data. The same potent growth-promoting signaling that makes it interesting also raises unaddressed safety questions, so the striking claims should be read with caution.