Dihexa

Dihexa is a small peptide derivative developed from angiotensin IV in Joseph Harding's laboratory at Washington State University, where it carries the development code PNB-0408. Chemically it is a modified dipeptide — a Tyr-Ile core capped with an N-terminal hexanoyl group and extended with a C-terminal 6-aminohexanoic amide (Hexanoyl-Tyr-Ile-Ahx-NH₂, ≈504.7 g/mol).

In the literature it is characterized as a potentiator of hepatocyte growth factor (HGF): it binds HGF with high affinity and enhances its activity at the c-Met receptor, a signaling axis studied for its role in synapse formation and neuronal health. A phosphate prodrug in this lineage (fosgonimeton, ATH-1017) was later taken into clinical development by Athira Pharma; Dihexa itself remains a research compound.

It is reputed in nootropic and biohacking communities as one of the most potent cognition-focused research peptides, popularly associated with memory formation, learning, and brain repair via the HGF/c-Met pathway.

Dihexa is widely discussed in nootropic circles for its purported ability to support memory, learning speed, and mental clarity, with researchers investigating its potentiation of hepatocyte growth factor signaling at the c-Met receptor — a pathway tied to synapse formation.

Biohackers anecdotally report interest in its reputed pro-cognitive and neuroregenerative potential, and preclinical studies have explored synaptogenesis, dendritic spine formation, and performance in animal models of cognitive impairment.

These are areas of active preclinical investigation and community interest rather than outcomes established in humans.

Preclinical work has examined Dihexa in models of cognitive impairment, where investigators measure synaptogenesis, dendritic spine formation, and learning-and-memory performance in animals. In neurotrophic assays reported by the originating lab, it compared favorably against reference growth factors on potency.

These are mechanistic and behavioral observations from controlled laboratory models. They describe what researchers have measured in cell culture and animal studies, not outcomes in humans.

Dihexa is supplied as a lyophilized powder and stored at -20°C, sealed and protected from light and moisture.

Unlike most research peptides, Dihexa is markedly hydrophobic and will not dissolve in plain bacteriostatic water. A common laboratory approach is a two-step reconstitution with stronger acid than the usual dilute acetic acid water: the powder is first wetted with a few drops of concentrated (glacial) acetic acid until it clears, then diluted to the working volume with bacteriostatic water; some laboratories use DMSO as the solvent instead. The working solution is held at 4°C for short-term use.