Cognitive · HGF/c-Met activator · Compounded 503A
Dihexa: angiotensin IV-derived synaptogenic peptide.
Dihexa (N-hexanoic-Tyr-Ile-(6) amino hexanoic amide) is a small peptide derived from angiotensin IV, developed at Washington State University. In preclinical models it is one of the most potent stimulators of synaptogenesis ever described — orders of magnitude beyond BDNF in some assays.
What Dihexa is
Dihexa (also called PNB-0408 or N-hexanoic-Tyr-Ile-(6) amino hexanoic amide) is a six-amino-acid-derived modified peptide engineered from the angiotensin IV scaffold by the Harding/Wright lab at Washington State University.
Its appeal is exceptional preclinical potency at promoting synaptogenesis — the formation of new functional connections between neurons. The published in-vitro work places it among the most potent synaptogenic compounds described.
It is investigational and dispensed through compounded pathways for cognitive-aging research. Human clinical trial data is limited.
How it works
Dihexa augments the binding of hepatocyte growth factor (HGF) to its receptor c-Met. HGF/c-Met signaling drives dendritic spine formation, synaptogenesis, and synaptic plasticity in the hippocampus and cortex.
By amplifying an endogenous neurotrophic system rather than introducing exogenous growth factor, dihexa preserves the spatial and temporal precision of natural synaptogenesis signaling.
Preclinical models of cognitive aging and Alzheimer's-like pathology have shown restoration of cognitive function after dihexa administration — the primary basis for human interest.
What patients use it for
Synaptogenesis
Preclinical potency at promoting new synapse formation places dihexa in a class of its own among investigational nootropics.
Cognitive support
In rodent models of age-related cognitive decline and Alzheimer-like pathology, dihexa restored learning and memory performance.
Neuroprotection
HGF/c-Met signaling is also neuroprotective — supporting neuron survival in models of oxidative stress and excitotoxicity.
Mechanism distinct from cholinergic nootropics
Unlike racetams or acetylcholinesterase inhibitors, dihexa works through structural synaptic remodeling — a different and complementary mechanism.
Evidence summary
McCoy AT et al. (J Pharmacol Exp Ther, 2013) demonstrated dihexa as a potent angiotensin IV-derived synaptogenic compound, restoring cognitive function in a scopolamine model of cognitive impairment.
Benoist CC et al. (J Pharmacol Exp Ther, 2014) showed dihexa-induced synaptogenesis in hippocampal slice cultures with sub-picomolar potency.
Wright JW, Harding JW (J Renin Angiotensin Aldosterone Syst, 2015) reviewed the angiotensin IV/HGF mechanism behind dihexa's cognitive effects.
Honest framing: dihexa has compelling preclinical potency but minimal published human clinical trial data. The clinical use exceeds the published evidence base.
Dosing and clinical context
General clinical context only. Kindr Health physicians determine the appropriate dose and protocol for each patient based on history and labs. This is not a prescription or dosing recommendation.
Most commonly dosed orally or transdermally — dihexa is one of the more orally bioavailable peptide-derived compounds.
Typical regimens involve daily dosing, with course-based use (8–12 weeks) common.
Compounded dihexa from licensed 503A pharmacies is the typical U.S. dispensing pathway. Not FDA-approved.
Safety and contraindications
Human safety data is limited. Generally well-tolerated in early clinical experience, though the published safety database is small.
Theoretical concerns: HGF/c-Met signaling is implicated in tumor biology. Patients with active malignancy should not use dihexa.
Contraindications: pregnancy, lactation, active or recent malignancy, known hypersensitivity. Use under physician supervision.
Who it's typically considered for
- Adults with cognitive aging concerns under physician supervision
- Patients in cognitive rehabilitation (post-TBI, post-stroke) under specialist guidance
- Adults already considering nootropic protocols who want a structural-synaptic mechanism
- Patients comfortable with the honest evidence framing — strong preclinical, minimal published clinical
Frequently asked questions
Is dihexa FDA-approved?
No. Dihexa is investigational; compounded preparations are dispensed by licensed 503A pharmacies under physician prescription for off-label use.
How quickly does dihexa work?
Subjective cognitive effects vary widely. Some patients report changes within 2–4 weeks; the underlying synaptogenic mechanism is expected to build over weeks of consistent dosing.
Dihexa vs Semax — which one?
Different mechanisms. Semax upregulates BDNF and modulates neurotransmitter tone. Dihexa drives structural synaptogenesis through HGF/c-Met. They're considered mechanistically complementary.
Does dihexa cause cancer?
There is no clinical evidence of carcinogenesis in human use, but HGF/c-Met signaling is implicated in some cancer biology — which is why active malignancy is a contraindication.
Can I take dihexa with caffeine or other nootropics?
Combination use is common in practice. The HGF/c-Met mechanism is non-overlapping with most other nootropic mechanisms. Discuss combinations with your physician.
Is dihexa safe long-term?
Long-term human safety data is limited. Short-course protocols with periodic reassessment are appropriate.
Will dihexa help in menopause-related brain fog?
Estrogen withdrawal in menopause affects hippocampal synaptic density. The mechanism is aligned — though direct RCT evidence in menopausal cognition is not yet published.
Sources
- McCoy AT et al. Evaluation of metabolically stabilized angiotensin IV analogs as procognitive/antidementia agents. J Pharmacol Exp Ther (2013). — pubmed.ncbi.nlm.nih.gov/23170086
- Benoist CC et al. The procognitive and synaptogenic effects of angiotensin IV-derived peptides are dependent on activation of the hepatocyte growth factor/c-Met system. J Pharmacol Exp Ther (2014). — pubmed.ncbi.nlm.nih.gov/24403549
- Wright JW, Harding JW. The brain hepatocyte growth factor/c-Met receptor system: a new target for the treatment of Alzheimer disease. J Alzheimers Dis (2015). — pubmed.ncbi.nlm.nih.gov/25471188
Considering Dihexa?
A Kindr Health physician reviews every longevity intake — peptides are prescribed only when medically indicated based on your history and labs. There is no charge for the initial review.
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Medically reviewed by Dr. Ana Lisa Carr, MD, MBA
Board-Certified Family Medicine Physician · Lead Provider / Medical Reviewer
NPI 1689841744 · Last reviewed: May 10, 2026
Last reviewed May 10, 2026. Compounded medications are prepared by FDA-registered 503A pharmacies and are not FDA-approved drug products. Prescriptions require a clinical evaluation; a Kindr Health physician determines eligibility. Not for use in pregnancy. This page provides educational information and is not medical advice.