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Dihexa
Last reviewed: June 11, 2026 by The Peptide Catalog Team
An angiotensin-IV-derived research peptide studied in animal models for synaptogenesis via the proposed HGF/c-Met pathway; the core mechanism papers were retracted in 2025 and no human trials exist. Angiotensin IV-derived research compound studied for synaptogenesis via the HGF/c-Met pathway. Preclinical and in-vitro only — no human trials, and the foundational mechanism papers were retracted in 2025.
Overview
Core Benefits
Key AdvantagesThese are educational summaries of commonly discussed effects in wellness/regenerative contexts, not guarantees.
Dihexa Results Timeline
ProgressionTimeline is illustrative and non-guaranteed. Outcomes vary and are commonly discussed alongside training, nutrition, sleep, and cycling practices.
How It WorksAngiotensin-IV-Derived Oligopeptide — Neuro / Synaptogenic (Preclinical Evidence Only; Core Papers Retracted)
Target → Signal → Effect → Outcomes
HGF / c-Met (MET) Receptor — Proposed
Dihexa is a synthetic oligopeptide derived from angiotensin IV (chemical name N-hexanoic-Tyr-Ile-(6)-aminohexanoic acid amide; CAS 1401708-83-5, also called PNB-0408). The leading hypothesis is that it potentiates hepatocyte growth factor (HGF) signaling at the c-Met (MET) receptor. Important caveat: the two core papers that established this mechanism (Kawas 2012, PMID 22129598; Benoist 2014, PMID 25187433) were retracted in 2025 following a Washington State University image-manipulation investigation. Treat the target as proposed, not confirmed.
Dendritic Spine Formation via PI3K-AKT — Proposed
Downstream of HGF/c-Met, the proposed signal runs through PI3K-AKT to promote dendritic spine formation and synaptogenesis— the basis for "BDNF-like" framing. A frequently cited claim that Dihexa is "seven orders of magnitude more potent than BDNF" comes from an in-vitro spine-density assay (McCoy 2013, PMID 23055539, which carries a 2021 Expression of Concern) and is assay-specific — it does not mean it is millions of times more effective in a living brain.
Improved Learning in Animal Models
The whole-organism evidence is rodent. Maze studies reported reversed scopolamine-induced deficits and improved learning in aged animals. The cleanest independent support is Sun 2021 (PMID 34827486): in APP/PS1 Alzheimer's-model mice, Dihexa improved Morris water-maze performance, raised synaptophysin, and lowered inflammatory cytokines via PI3K/AKT. That is a small rodent study — there is no human systemic outcome data.
Unknown in Humans
There are no human trials of Dihexa, so there is no evidence base for predicting what a person would notice. Community reports describe improved focus, memory, and verbal fluency, but they are inconsistent and some users report no effect — fully consistent with the absence of controlled human data. The closest human evidence in the same HGF/c-Met program, Athira's fosgonimeton, failed its Phase 2/3 Alzheimer's trial in 2024.
What Makes This Peptide Different
Dihexa is not a validated drug — it is a research chemical sold for laboratory use only. What distinguishes it is the proposed HGF/c-Met synaptogenic mechanism, an intriguing idea that nonetheless rests on a literature with serious integrity problems: the two foundational mechanism papers were retracted in 2025 (notices PMID 40312092 and PMID 40312093) after a misconduct finding, and a third carries an Expression of Concern. The most credible support is a single independent rodent study. There are no human trials, no FDA evaluation, and no established dose.
Dihexa Vendors
Dosing ProtocolSynaptogenesis / Cognition (Research / No Human Data)
Educational reference only. Individual responses vary. Consult healthcare provider before use.
Why This Dosing Protocol
Why the route debate? Community use spans oral capsules and transdermal (often DMSO-based) preparations. The claim that oral Dihexa is brain-penetrant traces back to the now-retracted papers, so it should not be treated as established.
Reconstitution Calculator
Dilution math and unit conversions. Prefilled using a common vial size for this peptide.
Open calculatorStorage & Handling
Storage at a glance
Proper storage temperatures, shelf life, reconstitution best practices, and travel tips for lyophilized and reconstituted peptides.
Handling specifics
Educational overview on storage, labeling, and traceability considerations for lab environments. Consult primary literature and vendor documentation for specifics.
- Freezer (-20°C): 1+ year
- Refrigerator (2-8°C): 1-3 months
- Room temperature: 2-3 weeks (emergency only)
- MUST refrigerate at 2-8°C
- 4-week maximum shelf life
- NEVER freeze after reconstitution
- Use bacteriostatic water for multi-dose
Molecular Structure
Modifications
- Hexapeptide angiotensin IV analog with N-/C-terminal protection
Sequence and properties provided for educational reference. Not for clinical dosing decisions.
FAQ
What is Dihexa?
Dihexa is a synthetic oligopeptide derived from angiotensin IV (chemical name N-hexanoic-Tyr-Ile-(6)-aminohexanoic acid amide; CAS 1401708-83-5, also called PNB-0408). It was developed at Washington State University and studied in animal models for cognitive effects, with a proposed mechanism centered on the HGF/c-Met pathway and synaptogenesis. It is sold as a research chemical — there are no human clinical trials, no FDA approval, and no established dose.
How strong is the evidence behind Dihexa?
Thin and complicated. All published data is preclinical (animal and in-vitro), and the two core mechanism papers from the original WSU lab (Kawas 2012; Benoist 2014) were retracted in 2025after a misconduct investigation found image manipulation; a third (McCoy 2013) carries a 2021 Expression of Concern. The cleanest independent support is a 2021 study in Alzheimer's-model mice (Sun et al., PMID 34827486) — a small rodent study. No human trial has confirmed any cognitive benefit.
Is Dihexa really 'seven orders of magnitude more potent than BDNF'?
That figure comes from a single in-vitro dendritic-spine assay (McCoy 2013) that compared picomolar Dihexa to nanomolar BDNF. It is assay-specific and does not mean Dihexa is millions of times more effective in a living brain. The paper it appears in also carries an Expression of Concern, so the claim should be read with caution.
Has Dihexa been tested in humans?
No. There are no human trials of Dihexa itself. The closest human evidence in the same HGF/c-Met program is Athira Pharma's fosgonimeton (ATH-1017) — a structurally distinct molecule (descriptions conflict on the exact relationship). Its Phase 2/3 LIFT-AD Alzheimer's trial failed its primary endpoint in 2024. That is the closest human data in the class, and it was negative — it should not be read as evidence Dihexa works.
Is there a proven Dihexa dose?
No. Because there are no human trials, there is no validated dose. Community sources report roughly 5-20 mg per day (oral or transdermal), usually once daily with cycling — but those figures come from vendor copy and forums, not pharmacokinetic data. A widely repeated "~12.8-day half-life" appears only in vendor copy with no peer-reviewed source.
How long does reconstituted peptide last?
Once mixed with bacteriostatic water, peptides remain stable for up to 4 weeks when refrigerated at 2-8°C (36-46°F). Unopened powder can last 1+ year in the freezer. Get our complete Storage & Travel Guide.
Is this peptide legal to purchase?
Peptides sold "for research purposes only" are legal to purchase in the US, but are not FDA-approved for human use outside of specific medical applications. Always consult a healthcare provider before use.
New to peptides?
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Dihexa Research Articles
Dihexa Dosage: What the Community Reports
Dihexa's 5-20 mg/day dose comes from forums, not trials. See the oral-vs-transdermal route debate and the 2025 retractions behind it.
side-effectsDihexa Side Effects: The No-Human-Data Reality
Dihexa has zero human safety data and a retracted mechanism literature. The theoretical cancer concern and anecdotal effects, graded by source.
resultsDihexa Timeline: What the Evidence Shows
No placebo-controlled human data sets a Dihexa timeline. Here's the gap between rodent onset data and community-reported onset, each labeled.
buying-guideBuy Dihexa: Price, COA & Cost Per Week
Only 1 vetted Dihexa source right now: $69.99 a vial, $0.20/mg. Codes save up to 10%. COA status and real cost per week.
Compare Dihexa to alternatives
Side-by-side mechanism, dose, half-life, and vendor pricing.
Disclosure: we may earn affiliate commission from qualifying purchases. Educational information only — not medical advice.