Dihexa is an experimental cognitive peptide that may help the brain build stronger connections between neurons instead of just temporarily boosting neurotransmitters like many nootropics do. It works through the HGF c Met pathway, Structural basis of the activation of c MET receptor Nature Communications Dihexa (also known as PNB 0408) is an experimental small molecule derived from angiotensin IV. It was engineered to cross the bloodbrain barrier and has shown synaptogenic effects in preclinical models. The often quoted Frontiers HGF and MET: From Brain Development to Neurological Disorders