Dihexa

Research-Grade

Dihexa (N-hexanoic-Tyr-Ile-(6) aminohexanoic amide) is a synthetic peptide-derived compound designed by Dr. Joseph Harding and colleagues at Washington State University as a metabolically stable analog of angiotensin IV. Unlike angiotensin IV, which is rapidly degraded in circulation, Dihexa resists aminopeptidase cleavage and crosses the blood-brain barrier after oral or subcutaneous administration. The primary mechanism involves potentiation of hepatocyte growth factor (HGF) signaling through its receptor c-Met. HGF/c-Met signaling promotes dendritic spine formation, synaptogenesis, and neuronal survival — processes fundamental to memory consolidation and cognitive function. In preclinical studies, Dihexa augmented HGF binding to c-Met by stabilizing the ligand-receptor complex, effectively amplifying a neurotrophic signal that naturally declines with aging. In a 2013 paper published in the *Journal of Pharmacology and Experimental Therapeutics*, Dihexa restored spatial learning in aged rats and scopolamine-impaired models at picomolar concentrations — making it approximately 10 million times more potent than BDNF in this assay. The compound also rescued cognitive deficits in a bilateral hippocampal injection model of neurodegeneration. No human clinical trials have been conducted. Dihexa remains a research compound with significant interest in the nootropic community but no established human safety or dosing data.