Dihexa

A synthetic hexapeptide analog of angiotensin IV, developed by Harding et al. at Washington State University. One animal study showed potent neurotrophic effects (claimed 10 million times more potent than BDNF in promoting synaptogenesis in vitro). Zero human studies of any kind — no RCTs, no pharmacokinetic data, no safety data in humans. This is the least-studied peptide commonly sold as a supplement. The complete absence of human safety data makes it a significant unknown risk. Sold as a 'research chemical' only.