Dihexa, an oligopeptide drug, is an orally active and blood-brain barrier-permeable angiotensin IV analog. Dihexa binds to hepatocyte growth factor ( HGF ) with high affinity ( K d =65 pM) and potentiates its activity at its receptor, c-Met. Dihexa exhibits excellent antidementia activity and improves cognitive function in animal models. Dihexa may have therapeutic potential as a treatment Alzheimer’s disease .