Dihexa
Angiotensin-IV-Derived Peptidomimetic — Preclinical Synaptogenesis Research
Dihexa (PNB-0408) — Angiotensin-IV-Derived Research Peptide (Preclinical)
Last reviewed: August 2026
Dihexa is a small peptide developed by researchers at Washington State University, derived from angiotensin IV (a fragment of the blood pressure hormone angiotensin). It was specifically designed to cross the blood-brain barrier — a major challenge for most peptides — and to potently stimulate synaptogenesis: the formation of new synaptic connections between neurons.
Dihexa is proposed to work through the HGF/c-Met signaling pathway, potentially potentiating HGF's activity at the c-Met receptor and promoting synaptogenesis. Important caveat: some foundational mechanism papers have been retracted or face reproducibility concerns, so the HGF/c-Met mechanism should not be stated as established fact. In animal studies from WSU, Dihexa was reported to be approximately 10 million times more potent than BDNF at promoting synaptogenesis — a preclinical claim that requires independent replication.
Synapse loss is the primary correlate of cognitive decline in Alzheimer's disease and other neurodegenerative conditions. A compound that potently stimulates synaptogenesis — the rebuilding of those connections — is of enormous potential interest for neurodegenerative disease research. The WSU research team's data is compelling, though independent replication has been limited and the compound is still in early-stage research.
Dihexa is a preclinical research compound with no completed human clinical trials. Some foundational mechanism papers have been retracted. The animal model data is intriguing but has not been independently replicated in humans. It should be treated as early-stage preclinical research only.
What is Dihexa?
Dihexa (PNB-0408) is a small molecule peptidomimetic derived from angiotensin IV, developed by researchers at Washington State University. It is one of the most potent pro-cognitive compounds identified in preclinical research, with reported activity approximately 7 orders of magnitude (10 million times) more potent than BDNF in promoting synaptogenesis in hippocampal cell culture models.
The proposed mechanism centers on the hepatocyte growth factor (HGF) / c-Met signaling pathway. Important note: some foundational mechanism papers attributing Dihexa's cognitive effects to HGF/c-Met pathway activation have been retracted or face reproducibility concerns. Dihexa has no completed human clinical trials. All evidence is from animal models.
- Dihexa (N-hexanoic-Tyr-Ile-(6) aminohexanoic amide) is a small peptidomimetic derived from angiotensin IV, engineered at Washington State University to cross the blood-brain barrier. Note: some foundational mechanism papers have been retracted; no human clinical trials have been completed.
- Proposed mechanism: Dihexa may potentiate HGF activity at the c-Met receptor. However, some foundational mechanism papers have been retracted or face reproducibility concerns. The HGF/c-Met pathway as the primary mechanism of cognitive enhancement is not established.
- WSU researchers reported Dihexa is approximately 10 million times more potent than BDNF at promoting synaptogenesis in vitro — a claim that has attracted significant research interest but requires independent replication in vivo.
- Animal studies showed Dihexa reversed cognitive deficits in scopolamine-induced amnesia models and improved performance in Morris water maze tasks, suggesting potential relevance to Alzheimer's disease and other synapse-loss conditions.
- Unlike most peptides, Dihexa is orally bioavailable and CNS-penetrant due to its lipophilic hexanoic acid modification — a key design feature that distinguishes it from most research peptides which require parenteral administration.
Molecular Composition
Dihexa is a modified tripeptide with the structure N-hexanoyl-Tyr-Ile-Leu-OH, derived from the C-terminal tripeptide of angiotensin IV (Ang IV). The N-hexanoyl modification at the N-terminus dramatically enhances lipophilicity and blood-brain barrier penetration compared to the parent angiotensin IV peptide. The molecular weight is 397.55 Daltons.
The compound is classified as a peptidomimetic rather than a standard peptide, as the N-hexanoyl modification confers drug-like properties including oral bioavailability and CNS penetration.
How Does It Work?
Dihexa is proposed to promote synaptogenesis via HGF/c-Met signaling (preclinical only; some foundational mechanism papers have been retracted; no human trials completed).
Dihexa is proposed to act as a potentiator of hepatocyte growth factor (HGF) binding to its receptor c-Met, a receptor tyrosine kinase expressed on neurons throughout the brain. The proposed downstream pathways include PI3K/Akt (neuronal survival), MAPK/ERK (cell proliferation), and Rac1/Cdc42 (actin cytoskeleton remodeling for synaptogenesis).
**Critical caveat:** Some foundational mechanism papers attributing Dihexa's cognitive effects to HGF/c-Met pathway activation have been retracted or face reproducibility concerns. The HGF/c-Met pathway as the primary mechanism of cognitive enhancement is not established. McCoy et al. (2013) at Washington State University demonstrated preclinical cognitive effects in rodent models, but these findings have not been independently replicated in human trials. Dihexa has no completed human clinical trials.
Key Research Pathways
HGF / c-Met Potentiation
Potentiates HGF binding to c-Met receptor tyrosine kinase, activating downstream signaling cascades that drive synaptogenesis.
PI3K / Akt Neuronal Survival
c-Met-mediated PI3K/Akt activation promotes neuronal survival and inhibits apoptosis in hippocampal and cortical neurons.
Rac1 / Cdc42 Synaptogenesis
Activates Rho GTPases Rac1 and Cdc42, driving actin cytoskeleton remodeling for dendritic spine formation and synaptogenesis.
Hippocampal Neurogenesis
Promotes neurogenesis in the hippocampal dentate gyrus, contributing to the cellular substrate of learning and memory.
Key Findings from the Literature
- ~10 million times more potent than BDNF in promoting synaptogenesis in hippocampal cultures (McCoy et al., 2013)
- Reverses cognitive deficits in aged rats and scopolamine-induced amnesia models
- Proposed HGF/c-Met signaling mechanism (some foundational papers retracted; mechanism not established)
- Promotes hippocampal neurogenesis in the dentate gyrus
- Oral bioavailability and blood-brain barrier penetration due to N-hexanoyl modification
- Neuroprotective effects in Alzheimer's disease pathology models
Important Research Context
Research References
Peer-reviewed literature supporting the research profile of Dihexa
The following peer-reviewed studies form the primary evidence base for Dihexa's research profile. All references are sourced from PubMed, NCBI, and peer-reviewed scientific journals. Published research is available through PubMed, NCBI, and peer-reviewed biomedical journals.
- 1.
McCoy AT, et al. Evaluation of metabolically stabilized angiotensin IV analogs as procognitive/antidementia agents. Journal of Pharmacology and Experimental Therapeutics. 2013.PMID: 23055539
Dihexa demonstrated potent procognitive effects in rodent models of cognitive impairment, exceeding BDNF activity.
- 2.
Benoist CC, et al. Facilitation of hippocampal synaptogenesis and spatial memory by C-terminal truncated Nle1-angiotensin IV analogs. Journal of Pharmacology and Experimental Therapeutics. 2011.PMID: 21719467
Angiotensin IV analogs including dihexa promote hippocampal synaptogenesis and spatial memory formation.
Dihexa
Cognitive Research
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Technical Specifications
| Compound Class | Peptidomimetic (N-hexanoyl modified tripeptide) |
| Molecular Weight | 397.55 Da |
| Target Pathway | HGF / c-Met receptor tyrosine kinase |
| Potency vs. BDNF | ~10⁷ fold more potent in synaptogenesis assays |
| BBB Penetration | Yes — N-hexanoyl modification enhances lipophilicity |
| Available Sizes | 100mg vials |
| Form | Lyophilized powder |
| Purity | ≥99% (third-party tested) |
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Other Compounds in This Guide
Supporting Research
Dihexa is a hexapeptide angiotensin IV analog studied preclinically for cognitive enhancement. Key mechanism papers citing HGF/c-Met pathway activation have been retracted or face reproducibility concerns. No human clinical trials have been completed.
References
- McCoy AT, et al.PRECLINICAL — rodentJournal of Pharmacology and Experimental Therapeutics. 2013. PubMedOriginal rodent study demonstrating cognitive enhancement by Dihexa in spatial memory tasks; HGF/c-Met mechanism proposed but later questioned.
Research Databases
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