AngIV Analog Dihexa Rescues Cognitive Impairment and Recovers Memory in the APP PS1 Mouse via the PI3K AKT Signaling Pathway Techmed Scientists created a peptide one million times stronger than the brain's natural growth factor sound dramatic. But strength in biology does not always mean better or safer. The brain's key 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 RCSB PDB 4HZG: Structure of haloalkane dehalogenase DhaA from Rhodococcus rhodochrous Zenity Bio Labs