PNB-0408 · HGF/MET Activator · Cognitive Enhancement
A small peptide derived from angiotensin IV with extraordinarily potent cognitive enhancement properties — reported to be up to 10 million times more potent than BDNF at promoting synaptogenesis (new synapse formation). Dihexa activates the hepatocyte growth factor/MET receptor system to stimulate new neural connections, with potential applications in cognitive decline, neurodegeneration and traumatic brain injury.
Dihexa (PNB-0408) is a small peptide derived from angiotensin IV, developed by Joseph Harding and colleagues at Washington State University. It acts as an agonist of the hepatocyte growth factor (HGF)/MET receptor signalling system — a pathway involved in neuronal survival, synaptic plasticity and neuroregeneration. In published research, Dihexa has been described as the most potent pro-cognitive compound ever identified, with synaptogenic activity reported to be approximately 10 million times more potent than BDNF on a molar basis.
Dihexa's primary cognitive enhancement mechanism is synaptogenesis — the formation of new synaptic connections between neurons. While most nootropic compounds (including Semax) work through BDNF to support existing neurons and their plasticity, Dihexa specifically drives the physical formation of new synapses. This makes it mechanistically unique and potentially more powerful for cognitive enhancement and neurological recovery than BDNF-pathway compounds.
Aged rats treated with Dihexa performed significantly better in spatial learning tasks (Morris water maze) than untreated controls, with improvements comparable to young adult rats. The compound improved cognitive function in models of Alzheimer's disease, traumatic brain injury and cognitive aging. Critically, the effects were sustained after discontinuation — suggesting actual structural neural changes rather than acute pharmacological effects.
Dihexa remains exclusively in preclinical research — no human clinical trials have been completed. The extraordinary potency numbers come from in vitro and animal studies. Translation to human cognitive enhancement is plausible given the mechanism but entirely unconfirmed. This is one of the most exciting compounds in the nootropic research space but also one with the most significant knowledge gaps regarding human safety and dosing.