Dihexa dosing & administration
Angiotensin IV-derived oligopeptide that potentiates hepatocyte growth factor to drive synaptogenesis and cognitive enhancement with extraordinary potency
Written by Michael Carroll — Owner, Director of Research · Reviewed by the Peptide Initiative Research Team · Editorial standards
Dosing
How much do I take?
Oral: Taken by mouth as a capsule, tablet, or liquid.
Bioavailability Varies by compound — many peptides are largely broken down in the gut, so little reaches the blood intact; some small molecules absorb well.
3 documented dose levels — separate regimens, not a titration schedule
5–8 mg
Frequency
Once daily
Duration
2–4 weeks
8–20 mg
Frequency
Once daily
Duration
4–6 weeks
Timing
Best time to take
Take Dihexa at the same time each day for consistent blood levels. Morning dosing with breakfast is often preferred, but follow your healthcare provider's specific instructions.
With food?
Dihexa can typically be taken with or without food. Taking it with a light meal may help reduce any GI discomfort. Avoid taking with grapefruit juice or high-fat meals unless specifically directed.
If stacking
Dihexa should be used as directed by your healthcare provider. If combining with other medications or supplements, discuss potential interactions with your provider. Avoid combining with compounds that have overlapping mechanisms unless specifically guided by a medical professional.
Adjusting your dose
Increase if
- You have been at the starting dose for 2+ weeks with good tolerance and want enhanced cognitive effects
- You are not experiencing noticeable cognitive improvements at the current dose after 3-4 weeks
- You are an experienced nootropic user with established tolerance to neurotropic compounds
Decrease if
- You experience persistent headaches or sleep disturbances
- You notice excessive emotional sensitivity or mood instability
- You want to maintain cognitive benefits while minimizing c-Met pathway activation
Signs of right dose
- Improved ease of learning new information and skills
- Enhanced memory recall — both short-term and long-term
- Better verbal fluency and word retrieval
- Vivid but not disruptive dreams (indicating hippocampal engagement)
- Stable mood with improved cognitive performance under stress
Administration
How do I use it?
Reconstitution
What you need
Injection
Route
Dihexa is administered Oral (capsule/tablet)—no injection required
Best sites
Storage
Before reconstitution
Store Dihexa in the refrigerator at 36-46°F (2-8°C) in its original packaging. Protect from light and moisture. Do not freeze. Check the expiration date before use. Some formulations may be stored at room temperature for limited periods—check your specific product labeling.
After reconstitution
Once reconstituted, Dihexa should be kept refrigerated at 36-46°F (2-8°C) and used within the timeframe specified on your product labeling (typically 14-28 days). Label the vial with the reconstitution date. Do not use if the solution appears cloudy, discolored, or contains particles.
Signs of degradation — discard the vial
Sample daily schedule
Morning
10 mg (1 capsule) injection
Site: Oral — swallow capsule with water, or sublingual (powder under tongue)
Take at the same time each morning. Due to the long half-life, consistent timing is less critical than with short-acting compounds, but morning dosing helps avoid any potential sleep disruption. Pair with Alpha-GPC or citicoline for optimal synapse function support.
Safety
Is it safe?
Side effects
Commonly reported: Headache, Vivid dreams or altered sleep patterns, Emotional sensitivity, Mild fatigue during adjustment
Less common: Gastrointestinal discomfort
Stop and seek help if
- Persistent severe headaches that do not resolve with dose reduction
- Significant mood instability or personality changes
- Any suspicious lumps, unexplained weight loss, or other potential cancer symptoms
- Completion of planned cycle duration (4-6 weeks recommended maximum)
- Adverse interaction with other medications or supplements
Dihexa is a research compound with no FDA approval and limited human safety data. All use is at the individual's own risk. The long half-life (~12 days) means effects persist for weeks after discontinuation. Consult a healthcare provider before using any research peptide, and report any concerning symptoms immediately.
Flagged pairings
- ACE inhibitors / ARBs — Dihexa is derived from the renin-angiotensin system (angiotensin IV). ACE inhibitors and angiotensin receptor blockers may alter the balance of RAS peptides and potentially interact with dihexa's mechanism. Use with caution and monitor blood pressure.
- Immunosuppressants — c-Met signaling plays roles in immune function and tissue repair. Immunosuppressive therapy may alter the downstream effects of HGF/c-Met activation by dihexa.
Published research
What the studies show
Benoist CC, Kawas LH, Zhu M, Bhatt D, Bhatt S, Bhatt A, Wright JW, Harding JW · 2014
RETRACTED (April 2025). This paper was withdrawn by the Journal of Pharmacology and Experimental Therapeutics at the editor's request, following a Notice of Concern issued in 2021. A Washington State University investigation determined that Figures 1B and 2A/C, along with data submitted in a subsequent erratum, contained falsified and/or fabricated data — Western blot bands copied between separate experiments, band intensity digitally altered, and identical images reused as distinct results. The investigation found authors Leen H. Kawas and Joseph W. Harding solely responsible. This citation is retained on the record for transparency. Its findings should not be treated as evidence, and the HGF/c-Met dependency claim it originated is not independently established.
Wright JW, Kawas LH, Harding JW · 2015
After 20+ years of development, dihexa solved a major puzzle: creating a brain-penetrating drug that survives digestion and crosses the blood-brain barrier, unlike its fragile parent molecule. The result is a compound that literally builds new brain circuitry by promoting the physical formation of synaptic connections.
Wright JW, Harding JW · 2015
Dihexa is the first drug designed from scratch to activate a brain growth pathway that's completely overlooked in typical Alzheimer's treatment. The peptide works by stimulating the brain's wiring machinery, physically rewiring memory centers and creating new functional brain networks that didn't exist before.
Sun X, Deng Y, Fu X, Li H, Li L, Shi Y, Qu W, Xie Z · 2021
In mice engineered with Alzheimer's disease genetics, oral dihexa restored their ability to navigate mazes and remember locations, effects comparable to the drug reversing the disease itself. The peptide also turned off the inflammatory brain cells that cause Alzheimer's damage and flipped on anti-inflammatory healing pathways.
Ho JK, Nation DA · 2018
Across 32 scientific studies, dihexa and related peptides improved memory in 8 out of 9 brain-damaged animal models, with the strongest benefits when the peptide was given right when learning happened. This suggests dihexa works best when your brain is actively forming new memories.
McCoy AT, Benoist CC, Wright JW, Kawas LH, Bule-Ghogare JM, Zhu M, Appleyard SM, Wayman GA, Harding JW · 2013
Describes the design of dihexa (N-hexanoic-Tyr-Ile-(6) aminohexanoic amide) from Nle1-AngIV: N- and C-terminal modifications to resist degradation (angiotensin-like peptides are rapidly metabolized by aminopeptidases) and increase barrier permeability, yielding an orally active, blood-brain-barrier-permeant analog. Reports antidementia activity in the scopolamine and aged (24-month) rat models, spinogenesis/synaptogenesis in hippocampal neurons at picomolar (10^-12 M) concentrations, and a terminal half-life of 12.68 days after IV dosing in rats (8.83 days IP). The journal published a Notice of Concern on this article in September 2021 (J Pharmacol Exp Ther 378:313); it is not among the three Harding-lab JPET papers retracted in April 2025.
Alzheimer's Drug Discovery Foundation (ADDF), Aging and Alzheimer's Prevention Program · 2021
ADDF neuroscientists' evidence review (last updated August 13, 2021): clinical trials none to date and no studies in humans published; no studies in animals or humans have examined dihexa's long-term safety; theoretically, activation of HGF and c-Met could promote tumorigenesis and cancer progression; half-life 12 days after IV and 8.8 days after IP administration in rats, unknown in humans.
Uribe PM, Kawas LH, Harding JW, Coffin AB · 2015
In the larval zebrafish lateral line, dihexa protected hair cells from the aminoglycosides neomycin and gentamicin, with 1 uM giving optimal protection; protection was attenuated by the HGF antagonist 6-AH and by inhibitors of Akt, TOR and MEK.
Scagliotti GV, Novello S, von Pawel J · 2013
Review: aberrant MET/HGF activation has been observed in many tumor types and promotes cellular proliferation and metastasis; preclinically, neoplastic and metastatic phenotypes of non-small cell lung cancer, hepatocellular carcinoma and gastric cancer cells were abrogated by MET inhibition.
Yap TA, Sandhu SK, Alam SM, de Bono JS · 2011
Review: the HGF/c-MET receptor tyrosine kinase pathway plays a pleiotropic role in cell proliferation, migration, invasion, angiogenesis and survival; despite physiological roles in embryonic development and tissue repair, it is frequently deregulated in a wide range of tumors and aberrant signaling has multifunctional effects in oncogenesis.
Head to head
Dihexa compared
Studied for
Conditions Dihexa has been researched in
Want the full picture?
The complete Dihexa research profile: mechanism of action, clinical studies, effectiveness timeline, and FAQ.