Dihexa

Status Not approved for human use; no registered human trialBest evidence E4Sources checked 2026-09-18

Dihexa is an engineered small molecule, not a peptide, developed from angiotensin IV research at Washington State University to activate the HGF/c-Met growth-factor pathway. Every finding is rodent. No human trial of Dihexa itself exists; a related compound, fosgonimeton, was carried into human trials instead.

What it is

Dihexa (N-hexanoic-Tyr-Ile-(6) aminohexanoic amide) is a small synthetic molecule developed at Washington State University by John Wright and Joseph Harding, derived from the brain renin-angiotensin system compound Nle1-angiotensin IV. It is not a peptide in the sense most entries on this site use the word; it is a designed, metabolically stabilised small molecule built to activate the hepatocyte growth factor (HGF)/c-Met receptor system, a growth-factor pathway involved in synapse formation. It has never been approved for human use anywhere, and it is not undergoing any registered human clinical trial.

The compound was licensed to M3 Biotechnology (later renamed Athira Pharma), a company the same researchers co-founded. Athira went on to develop a related but chemically distinct compound, fosgonimeton, through human Phase 2 and Phase 3 Alzheimer’s trials; those later-stage human trials were run on fosgonimeton, not on Dihexa itself, and the two should not be treated as interchangeable.

What has actually been tested

Every finding for Dihexa specifically comes from the same small group of review and mechanism papers by its own developers, describing rodent studies. Those papers report that Dihexa is orally active, crosses the blood-brain barrier, and facilitates memory consolidation and retrieval in animal models of Alzheimer’s disease by promoting the formation of new synaptic connections through HGF/c-Met activation.

No registered clinical trial of Dihexa itself was found on ClinicalTrials.gov. The compound has not, to the sources reviewed for this entry, been given to a human being in a published study.

What is not known

Whether Dihexa’s reported memory and synaptogenesis effects in rodents translate to a human being at any dose, by any route. No human trial exists.

Human pharmacokinetics, human safety, and human dosing at any level.

Whether Dihexa shares the safety and efficacy profile of fosgonimeton, the related compound its own developers carried into human trials instead. The two are chemically distinct molecules from the same research program, not the same drug under two names.

What is not known

Whether Dihexa’s memory and synaptogenesis effects in rodents reproduce in a human being, at any dose, by any route. No human trial exists.

Human pharmacokinetics, safety and dosing at any level.

Whether Dihexa behaves like fosgonimeton, the chemically distinct compound from the same research program that was actually carried into human Alzheimer’s trials.

Doses used in published research

No published study has administered this compound to a human being, so no dose appears in the literature and none has been established.

Amounts above record what a named source reported administering in a study. They are not a recommendation, not a protocol, and not instructions.

Converting a vial and a syringe into a draw volume is a separate, mechanical question from what amount to use. The reconstitution calculator does that arithmetic for peptide, HCG, and HGH vials.

What circulates E5

Figures reported online. Not dosing, not verified, not endorsed.
Reported use	Route	Amount reported	Frequency	Reported length
Cognitive support, general	Subcutaneous or oral	5 to 10 mg per dose	Once daily	Often cycled, weeks

Circulating cognitive-support material for Dihexa describes milligram-range oral or subcutaneous doses. There is no human trial of any kind to check that figure against. The rodent research this compound is based on describes it as engineered for extremely high potency at oral doses far below typical peptide drug quantities, without publishing a figure that scales cleanly to a milligram human dose; the circulating figure is not derived from, or comparable to, anything published for this compound.

Recorded as an observation about what is published elsewhere. No figure here is a dose, a protocol, or a recommendation, and nothing in this section is evidence that any amount is safe or effective.