Dihexa & Tesofensine Bundle Pack: Amazon.com: Industrial & Scientific My research on Dihexa #2: With TD use : r Nootropics 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 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