New — Free Peptide Starter Guide (2026): 13 chapters, 34 cited studies

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Dihexa

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

Dihexa is a potent experimental oligopeptide derived from angiotensin IV that dramatically enhances synaptogenesis. Preclinical research shows cognitive enhancement orders of magnitude more potent than BDNF — it is considered one of the most powerful nootropic compounds in research, but has very limited human safety data.

Half-Life

Unknown (limited pharmacokinetic data)

Route

Oral, SubQ, Topical

Category

Cognitive Enhancement

Studies

18 references

Key Benefits

  • Dramatically increases synapse formation (potentially 10 million× more potent than BDNF in animal models)
  • Enhances memory and learning
  • May reverse cognitive decline
  • Improves neuroplasticity and executive function
  • Long-lasting cognitive benefits from short courses
  • Potential therapeutic agent for Alzheimer's

Mechanism of Action

Dihexa binds to hepatocyte growth factor (HGF) and potentiates its activity at c-Met receptors. This leads to dramatically enhanced synaptogenesis (formation of new synapses), increased dendritic spine density, and improved neuroplasticity. The HGF/c-Met pathway is critical for brain development, learning, and memory consolidation. Animal studies show cognitive improvements orders of magnitude more potent than BDNF.

Dosing Protocols

Experimental Protocol

Dose
5–10 mg
Frequency
Daily
Timing
Morning
Cycle
2–4 weeks on, 2–4 weeks off

Extremely potent — start at lowest effective dose. Very limited human safety data. Topical application also investigated due to skin permeability. Cycles with breaks strongly recommended given unknown long-term profile.

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Side Effects

  • Headache
  • Irritability
  • Brain fog during washout period
  • Unknown long-term effects (insufficient data)

Contraindications

Experimental compound — limited human safety data. History of cancer (HGF/c-Met pathway theoretical concern). Pregnancy or breastfeeding. Mental health conditions.

Storage

Store at −20°C. Protect from light.

  1. 1.
    Therapeutic Peptides in Orthopaedics: Applications, Challenges, and Future Directions

    Rahman OF, Lee SJ, Seeds WA · Journal of the American Academy of Orthopaedic Surgeons. Global research & reviews · 2026ReviewPubMed Verified

  2. 2.
    Effects of an Angiotensin IV Analog on 3-Nitropropionic Acid-Induced Huntington's Disease-Like Symptoms in Rats

    Wells RG, Azzam AF, Hiller AL, Sardinia MF · Journal of Huntington's disease · 2024PubMed Verified

  3. 3.
    Efficiently generate functional hepatic cells from human pluripotent stem cells by complete small-molecule strategy

    Pan T, Wang N, Zhang J, Yang F, Chen Y, Zhuang Y et al. · Stem cell research & therapy · 2022PubMed Verified

  4. 4.
    AngIV-Analog Dihexa Rescues Cognitive Impairment and Recovers Memory in the APP/PS1 Mouse via the PI3K/AKT Signaling Pathway

    Sun X, Deng Y, Fu X, Wang S, Duan R, Zhang Y · Brain sciences · 2021PubMed Verified

  5. 5.
    Stem cell, Granulocyte-Colony Stimulating Factor and/or Dihexa to promote limb function recovery in a rat sciatic nerve damage-repair model: Experimental animal studies

    Weiss JB, Phillips CJ, Malin EW, Gorantla VS, Harding JW, Salgar SK · Annals of medicine and surgery (2012) · 2021PubMed Verified

  6. 6.
    Cognitive benefits of angiotensin IV and angiotensin-(1-7): A systematic review of experimental studies

    Ho JK, Nation DA · Neuroscience and biobehavioral reviews · 2018Meta-AnalysisPubMed Verified

  7. 7.
    Small-Molecule-Directed Hepatocyte-Like Cell Differentiation of Human Pluripotent Stem Cells

    Mathapati S, Siller R, Impellizzeri AA, Lycke M, Vegheim K, Almaas R et al. · Current protocols in stem cell biology · 2016PubMed Verified

  8. 8.
    Small-molecule-driven hepatocyte differentiation of human pluripotent stem cells

    Siller R, Greenhough S, Naumovska E, Sullivan GJ · Stem cell reports · 2015PubMed Verified

  9. 9.
    Hepatocyte growth factor mimetic protects lateral line hair cells from aminoglycoside exposure

    Uribe PM, Kawas LH, Harding JW, Coffin AB · Frontiers in cellular neuroscience · 2015PubMed Verified

  10. 10.
    The Brain Hepatocyte Growth Factor/c-Met Receptor System: A New Target for the Treatment of Alzheimer's Disease

    Wright JW, Harding JW · Journal of Alzheimer's disease : JAD · 2015ReviewPubMed Verified

  11. 11.
    The development of small molecule angiotensin IV analogs to treat Alzheimer's and Parkinson's diseases

    Wright JW, Kawas LH, Harding JW · Progress in neurobiology · 2015ReviewPubMed Verified

  12. 12.
  13. 13.
    The procognitive and synaptogenic effects of angiotensin IV-derived peptides are dependent on activation of the hepatocyte growth factor/c-met system

    Benoist CC, Kawas LH, Zhu M, Tyson KA, Stillmaker L, Appleyard SM et al. · The Journal of pharmacology and experimental therapeutics · 2014PubMed Verified

  14. 14.
    Effect of structure on the interactions between five natural antimicrobial compounds and phospholipids of bacterial cell membrane on model monolayers

    Nowotarska SW, Nowotarski KJ, Friedman M, Situ C · Molecules (Basel, Switzerland) · 2014PubMed Verified

  15. 15.
    Evaluation of metabolically stabilized angiotensin IV analogs as procognitive/antidementia agents

    McCoy AT, Benoist CC, Wright JW, Kawas LH, Bule-Ghogare JM, Zhu M et al. · The Journal of pharmacology and experimental therapeutics · 2013PubMed Verified

  16. 16.
    Dimeric DOTA-alpha-melanocyte-stimulating hormone analogs: synthesis and in vivo characteristics of radiopeptides with high in vitro activity

    Bapst JP, Froidevaux S, Calame M, Tanner H, Eberle AN · Journal of receptor and signal transduction research · 2007PubMed Verified

  17. 17.
    Studies on the subcellular localization of the porphycene CPO

    Kessel D, Conley M, Vicente MG, Reiners JJ · Photochemistry and photobiology · 2005PubMed Verified

  18. 18.
    Localization of alveolar surfactant clearance in rabbit lung cells

    Rider ED, Ikegami M, Jobe AH · The American journal of physiology · 1992PubMed Verified

Medical disclaimer: This information is for educational purposes only and does not constitute medical advice. Many compounds listed are research chemicals not approved for human use. Always consult a qualified healthcare professional before starting any protocol.

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