What is the dosing range for Dihexa?

Dihexa is typically dosed at 10mg (low), 15mg (moderate), or 20mg (high) mg, administered Once daily (or every other day — long-lasting effects). These ranges are aggregated from preclinical research and community protocols — not medical dosing guidance.

What are the reported side effects of Dihexa?

Reported side effects of Dihexa include: Potential for pro-proliferative effects — HGF/c-Met pathway promotes cell growth (theoretical cancer concern at high doses), Headache (uncommon), Mental fatigue if overdosed, Long half-life means effects accumulate — take every other day initially, Limited long-term human safety data.

Nootropic

Dihexa

Also known as: PNB-0408, N-hexanoic-Tyr-Ile-(6) aminohexanoic amide

Dihexa is a research compound not approved for human use. Limited long-term safety data exists. For informational purposes only.

📚 Content aggregated from:2 peer-reviewed sources·r/Peptides community·PubMed / NCBI

Overview

Dihexa is a synthetic hexapeptide derived from angiotensin IV, developed at Washington State University. It is considered one of the most potent nootropic peptides known — in rodent models it outperforms BDNF itself for synaptogenesis and cognitive enhancement, acting through the hepatocyte growth factor (HGF) / c-Met receptor system. Unlike most nootropics, Dihexa is highly lipophilic and can be administered transdermally or orally.

Research Summary

Dihexa (PNB-0408) was developed by Joseph Harding and colleagues at WSU as a metabolically stable angiotensin IV analog. It binds hepatocyte growth factor (HGF), potentiating its interaction with the c-Met receptor — a pathway critical for dendritic branching, synapse formation, and synaptic plasticity. In rodent Alzheimer's and scopolamine-impaired models, Dihexa restored cognitive performance at doses ~7 orders of magnitude lower than BDNF. It readily crosses the blood-brain barrier due to its lipophilicity, unlike BDNF itself.

Dosing Range

low

10mg

moderate

15mg

high

20mg

Units: mg · Frequency: Once daily (or every other day — long-lasting effects)

Dosing ranges are aggregated from preclinical research and community protocols. Not medical dosing guidance.

Administration Routes

Oral (capsule)Transdermal (cream/lotion — lipophilicity makes this effective)Subcutaneous injection (less common)

Reconstitution Notes

Highly lipophilic — does not dissolve well in water. For oral use: encapsulate in oil-filled capsules or mix with a small amount of DMSO for transdermal. For injectable use: dissolve in propylene glycol or DMSO then dilute with saline. NOT water-soluble — do not attempt aqueous reconstitution alone.

Step-by-step reconstitution guide →

Supplies you'll need

Insulin Syringes (U-100)Reconstitution Needles Lambda BAC Water Alcohol Prep Pads

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Reported Side Effects

Potential for pro-proliferative effects — HGF/c-Met pathway promotes cell growth (theoretical cancer concern at high doses)
Headache (uncommon)
Mental fatigue if overdosed
Long half-life means effects accumulate — take every other day initially
Limited long-term human safety data

Research Papers

2 peer-reviewed sources

Dihexa (N-hexanoic-Tyr-Ile-(6) aminohexanoic amide) rescues cognitive decline in Alzheimer's disease models

Journal of Pharmacology and Experimental Therapeutics2012

Angiotensin IV and the AT4 receptor system

Pharmacological Reviews2006

Community Experiences

Aggregated from public forums. Anecdotal — not clinical evidence.

r/nootropics

Community experience with Dihexa — transdermal administration, dosing frequency, and cognitive effects.

View original thread

Overview

Dihexa is in a different class from most nootropic peptides. While compounds like Semax work by upregulating BDNF production, Dihexa acts downstream of BDNF — it potentiates HGF/c-Met signaling, which directly drives the structural changes BDNF initiates (dendritic branching, synapse formation, spine density). This distinction may explain why it outperforms exogenous BDNF itself in animal models: it amplifies the cellular machinery rather than flooding it with a ligand.

The HGF / c-Met Pathway

Hepatocyte Growth Factor was originally identified for liver regeneration. It was later discovered to be a critical CNS trophic factor:

Synaptogenesis — promotes formation of new synaptic connections
Dendritic branching — increases the number of dendritic spines (structural correlate of memory)
Neuroprotection — promotes neuronal survival after injury or excitotoxicity
Hippocampal plasticity — long-term potentiation support

Dihexa doesn't mimic HGF — it stabilizes the HGF-c-Met complex interaction, making existing HGF signaling dramatically more potent.

Lipophilicity: A Design Feature

Most peptides are hydrophilic and must be injected to bypass intestinal degradation and the blood-brain barrier. Dihexa was deliberately designed to be lipophilic:

Oral bioavailability is viable (fat-containing meal increases absorption)
Transdermal administration is effective — penetrates skin readily
Crosses the BBB without active transport mechanisms
Long half-life (effects persist for days, not hours)

Dosing Considerations

The long half-life requires careful dosing:

Start every other day — effects accumulate over days to weeks
Low doses (10mg) before escalating — more is not better with Dihexa
Cycles of 4–6 weeks with equal length washout — the receptor system needs time to reset
Stack with anxiolytics if overstimulation occurs (Selank, theanine)

Important Safety Note

The HGF/c-Met pathway promotes cell proliferation — the same mechanism that makes Dihexa pro-synaptic could theoretically promote growth of pre-existing malignant cells at very high doses. This is a theoretical concern (not demonstrated at research doses in healthy animals), but it warrants caution in individuals with cancer history.