Dihexa (PNB-0408) is a synthetic oligopeptide derived from angiotensin IV, developed at Washington State University by Dr. Joseph Harding. It is the most potent neurogenic peptide available, activating the HGF/c-Met receptor pathway to stimulate synaptogenesis and neurogenesis at picomolar concentrations — making it 7 to 10 million times more potent than BDNF for driving new synaptic connections. Uniquely among neurotrophic peptides, Dihexa is orally bioavailable and crosses the blood-brain barrier efficiently.