Gathering the record
Relay is organizing the evidence and source boundaries.
Experimental angiotensin-IV-derived peptidomimetic
An experimental compound discussed for memory and brain function. It is not a peptide medicine with established human benefits.
Evidence is explained by question. Dosing references show their own check dates.
60-second overview
Why people look into it, what studies found, and what is still unknown.
Educational information only. Evidence reviewed through July 31, 2026. Published studies, sponsor announcements, and trials without results are labeled separately. Evidence gaps apply to the specific finding beside them.
Research questions
Each label shows how much evidence supports that question.
What studies show
None identified. The evidence base consists of laboratory and animal studies plus official safety and search audits.
It is chemically distinct from native angiotensin IV and from unrelated HGF-pathway drug candidates.
HGF-pathway blockade reduced the observed rodent and cell effects.
These are proof-of-concept signals, not human nootropic evidence.
The evidence is not uniformly positive across disease models.
Claims for human memory, focus, neuroprotection, dementia treatment, or oral bioavailability are unproven.
FDA lacks essential information needed to determine whether such products could harm humans.
No approved Dihexa product or human therapeutic window exists.
Risks & unknowns
No human Dihexa efficacy, pharmacokinetic, dose-ranging, or safety trial was identified.
No direct evidenceA future exact-compound trial could change the evidence state.
Open sourceThe available information does not reliably show how often particular side effects occur.
Evidence boundaryUnder-detected or under-reported events must not be described as rare.
Relay has not verified which side effects led people to stop treatment in studies.
Evidence boundaryThis is an evidence gap, not proof that discontinuations did not occur.
Relay has not verified a compound-specific warning summary for this profile.
Evidence boundaryNot approved; no identified human exposure data Human exposure, target engagement, pharmacokinetics, cancer-related c-Met pathway implications, repeated-use toxicity, cognition outcomes, product identity, and every route-specific safety question.
This profile does not contain verified, product-specific emergency instructions.
Evidence boundaryRelay does not infer emergency guidance from study discontinuations, mechanism, or incomplete adverse-event reporting.
Dosing references
Each table labels its source and applies only to the named route, product, or study. An online example or community report is not an approved dose.
The reviewed evidence is preclinical. A rodent amount or a seller's chart does not establish a human dose.
What would fill this gap: A verified administered-human study of Dihexa with an exact regimen.
Dosing review checked Oct 20, 2026. Additional sources are available below.No route-specific preparation instructions were verified. A different route or product does not supply them.
Starting dose: the amount used at the beginning of the named label schedule or trial.
Maintenance: the ongoing amount described by that product label.
Trial target: the amount assigned to a study group. Different groups may stop increasing at different targets.
Published research investigated Dihexa in rodent learning models and cultured rat neurons to examine behavior, synaptic structure, and pathway dependence.
Population: Scopolamine-impaired and aged rats; cultured rat hippocampal neurons
Design: Rodent behavioral studies plus hippocampal neuron culture
Mechanisms
Dihexa (PNB-0408) is a metabolically stabilized AngIV-derived peptidomimetic designed for oral activity and brain exposure in rodents. Preclinical work reports facilitation of HGF/c-Met signaling, hippocampal spinogenesis, synaptogenesis, and improved performance in selected rodent cognitive models. An APP/PS1 mouse study linked effects to PI3K/AKT signaling, while a 2024 3-nitropropionic-acid Huntington-like model did not find efficacy on its target outcomes. No human clinical trial, dose-ranging study, pharmacokinetic study, or safety program was identified. FDA specifically reports no identified human exposure data for compounded dihexa acetate, making cognition, neuroprotection, route, dose, and safety claims unestablished.
A plausible mechanism can explain why a study was attempted. It does not prove that the compound improves a human outcome.
Research reference
A reference for the studies, populations, and routes behind this profile.
A small set of cell and rodent studies reports synaptic and behavioral effects; no human exposure was found.
Research depth describes how large and mature the overall record is. It does not tell you whether the results were positive.
Disease-model results are mixed and there is no human pharmacokinetic, efficacy, or safety program.
Confidence describes how reliable and consistent the conclusions are. It can be high for one outcome and low for another.
The strongest evidence type shows what the best-supported conclusions are actually based on.
Human findings are more directly relevant than animal or laboratory results, but they still apply only to the populations and outcomes studied.
Route-specific record
These are exposures used in cited research for a specific route and population—not an instruction for an individual.
Half-life describes how long it takes the measured amount in the body to fall by half. It is not a dosing recommendation.
Evidence can change by administration method. Findings from one route should not automatically be applied to another.
Evidence boundary: No verified human exposure, pharmacokinetic, efficacy, or safety study was located. Rodent behavior and cell morphology cannot establish human cognition benefit or resolve growth-pathway and cancer-related safety questions. Amounts shown describe cited research exposure—not a dosage recommendation.
Studies
Study arms are reported for transparency. They describe what researchers did in a defined record and do not transfer across identities, routes, formulations, or populations.
A later trial phase can ask a more mature question, but it does not guarantee a positive result, regulatory approval, or relevance outside the studied population.
Controlled 3-nitropropionic-acid rodent model
Rodents with chemically induced Huntington-like pathology
PNB-0408 did not show efficacy for preventing the targeted Huntington-like symptoms in this model.
Study administration: PNB-0408 or controls
Limitations: A negative result in one model does not settle every possible indication, but it counters universal neuroprotection claims.
Controlled APP/PS1 mouse experiment
APP/PS1 transgenic mice
The study reported improved cognition-related outcomes and altered inflammatory and PI3K/AKT measures.
Study administration: Intragastric Dihexa at two experimental amounts or controls
Limitations: APP/PS1 mice do not reproduce the full human disease, and treatment amounts and outcomes cannot be translated into human use.
Rodent cognition and neuronal-culture experiments with HGF/c-Met blockade
Scopolamine-impaired rats and cultured hippocampal neurons
Blocking HGF/c-Met signaling attenuated Dihexa-associated procognitive and synaptogenic effects.
Study administration: Dihexa with or without an HGF antagonist
Limitations: Mechanistic dependence in rodent systems does not prove safe or beneficial human MET modulation.
Rodent behavioral studies plus hippocampal neuron culture
Scopolamine-impaired and aged rats; cultured rat hippocampal neurons
Dihexa improved selected rodent spatial-learning outcomes and increased dendritic-spine measures in neuronal culture.
Study administration: Dihexa versus controls in preclinical protocols
Limitations: Rodent cognition and cell morphology do not establish human cognitive efficacy or safety; several pharmacokinetic claims rely on limited preclinical characterization.
ClinicalTrials.gov and FDA evidence review
Population not stated.
No registered human Dihexa trial was identified, and FDA reports no identified human exposure data for compounded dihexa acetate.
Study administration: Not stated in the current record.
Limitations: Searches can change over time, but the absence of human exposure prevents clinical claims.
Community
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Every structured report adds useful context about research setup, outcomes, and unwanted effects as the community dataset grows.
Publicly anonymous by default. Your account keeps reports editable and helps reduce duplicate submissions.Sources
2026-07-31
2026-07-31
2026-07-31
2024-03-01 · PMID 38489193
2021-11-12 · PMID 34827486 · DOI 10.3390/brainsci11111487
2014-11-01 · PMID 25187433 · DOI 10.1124/jpet.114.218735
2013-01-01 · PMID 23055539 · DOI 10.1124/jpet.112.199497