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Research peptide — not a dietary supplement
Dihexa is a research compound, not a regulated dietary supplement. It is typically administered by injection and sold “for research use only.” The evidence below is largely preclinical (animal and in-vitro) or early-stage, so no evidence score is assigned. This page is provided for transparency and education — it is not a recommendation to use. Consult a qualified healthcare provider, and be aware that purity, dosing, and legal status vary by jurisdiction.
What the evidence says
Most Dihexa studies are mechanism or observational rather than RCTs that measure a clinical effect — keep findings provisional.
Most evidence is from mixed-quality studies published 2013–2024.
Based on 4 studies
Confidence
Very lowBy outcome
The current evidence for Dihexa is insufficient to assign an evidence score, based on 4 indexed studies. A synthetic angiotensin-IV-derived peptide developed as a procognitive/anti-dementia research compound, promoted online as a potent nootropic. Honest appraisal: all efficacy data are in rodents and cell culture — there are no published human trials. Research-use-only. Representative study: PMID 23055539.
The commonly studied dose of Dihexa is No validated human dose. Grey-market oral/sublingual/topical 'nootropic' dosing is anecdotal and unsupported by any human study.. Individual needs vary — start at the lower end of the range and adjust based on how you respond.
Humanin
Mostly mechanism / observationalA mitochondrial-derived peptide (a sibling of MOTS-c) studied for cytoprotection, neuroprotection, and metabolic effects. Honest appraisal: the evidence is almost entirely cell-culture and animal work plus human biomarker associations — there are no human efficacy trials of administered humanin. Research-use-only.
Lactotripeptides
Last reviewed June 2026 · evidence from 4 studies · how we score
This information is for educational purposes only. It is not a substitute for professional medical advice. Always consult a qualified healthcare provider before starting, stopping, or changing any supplement or medication.
Dihexa (N-hexanoic-Tyr-Ile-(6) aminohexanoic amide, PNB-0408)
A synthetic angiotensin-IV-derived peptide developed as a procognitive/anti-dementia research compound, promoted online as a potent nootropic. Honest appraisal: all efficacy data are in rodents and cell culture — there are no published human trials. Research-use-only.
Dihexa's procognitive and synaptogenic effects are shown only in rodent and cell-culture studies; there are no human pharmacokinetic, efficacy, or safety trials, so the evidence is preclinical-only and the marketed nootropic claims are unvalidated in people.
Dihexa is a metabolically stabilized, blood-brain-barrier-penetrant analog of angiotensin IV, developed in academic labs as a candidate procognitive/anti-dementia agent.
In rodent and cell-culture studies it promotes synaptogenesis and improves learning and memory, and its activity appears to depend on the hepatocyte growth factor (HGF)/c-Met receptor system, which it is proposed to potentiate.
These properties have made it a popular grey-market 'nootropic,' marketed in oral, sublingual, and topical forms with claims of dramatic cognitive enhancement.
The honest evidence picture is that every efficacy and mechanism study is preclinical — rodents, brain slices, and cultured neurons; there are no published human pharmacokinetic, efficacy, or safety trials.
Because its proposed mechanism involves potentiating a growth-factor (HGF/c-Met) pathway implicated in cell proliferation, there is a theoretical proliferative/oncologic concern that has not been characterized in humans.
Dihexa is neither an approved drug nor a regulated dietary supplement; grey-market product carries the usual purity and content uncertainty. The score reflects preclinical-only evidence with no human data.
Dihexa's procognitive and synaptogenic effects are reported to depend on the hepatocyte growth factor (HGF)/c-Met receptor system, which it is proposed to potentiate.
In cultured neurons and rodent brain it promotes formation of new functional synapses, the proposed basis of memory enhancement.
As a metabolically stabilized angiotensin-IV analog it resists degradation and crosses the blood-brain barrier far better than the parent peptide.
How Dihexa works — from molecular targets to health outcomes. Click an edge to see supporting research.This visualization is in beta — pathways are being refined and expanded.
Tap node to isolate • Pinch to zoom • Tap edge for research
No validated human dose. Grey-market oral/sublingual/topical 'nootropic' dosing is anecdotal and unsupported by any human study.
Can be taken without food
| Form | Type |
|---|---|
| 💊None established (research compound) | Recommended |
Marketed grey-market in oral, sublingual, and topical forms with no clinical basis; oral bioavailability/BBB penetration in humans is unstudied.
Minimum: 4 weeks
Optimal: 8 weeks
Cycling: Not required
Note: No validated human dosing or schedule — dihexa is a preclinical research compound despite being sold online as a nootropic.
Dose-response data unavailable. The current published research for Dihexa does not provide sufficient dose-specific outcome data to generate reliable dose-response curves.
Refer to the Dosage & Timing section above for recommended dose ranges based on available evidence.
Improves learning and memory in rodent dementia models; not demonstrated in humans.
Promotes new synapse formation in cell and animal studies.
No published human pharmacokinetic, efficacy, or safety studies despite heavy online marketing.
Potentiating the HGF/c-Met growth pathway raises an uncharacterized proliferative/oncologic concern in humans.
Caution — potentiating the HGF/c-Met growth pathway raises a theoretical proliferative concern.
Avoid — no human safety data.
Research-use-only; not validated or recommended for human use.
Tip: No human safety data; effects are unquantified.
Timing is flexible for Dihexa — consistent daily use matters more than the time of day. No validated human dosing; sold in oral, sublingual, and topical forms with no clinical basis.
Dihexa should be used with caution — talk to a healthcare provider before taking it. The most commonly reported side effects are unknown human effects. Use caution if any of these apply to you: Pregnancy / breastfeeding; Any non-research human use (no safety data).
Two milk-casein-derived tripeptides — Val-Pro-Pro (VPP) and Ile-Pro-Pro (IPP) — produced by fermenting milk with Lactobacillus helveticus or hydrolysing casein. They inhibit ACE in vitro and have been studied extensively for blood pressure. Honest appraisal: multiple meta-analyses find a small, statistically-significant drop in systolic/diastolic BP, but the effect is modest, heterogeneous, larger in Japanese than Western trials, and dented by clear publication bias plus outright-null trials (e.g. the Dutch Engberink RCT).