COGNITIVE · Oral
Dihexa.
Strongest known neurogenic compound — synaptogenesis and memory
How it works
Class & mechanism.
Class
Angiotensin-IV Analogue — Small-Molecule Nootropic Peptide
Mechanism
Dihexa (N-hexanoic-Tyr-Ile-(6) aminohexanoic amide) is a synthetic hexapeptide derived from the angiotensin IV fragment Ile-Val-Tyr-Ile-His-Pro and designed to be CNS-penetrant and orally bioavailable. Its primary mechanism is agonism at the hepatocyte growth factor / Met receptor (HGF/Met) system — the same pathway that drives synaptogenesis, dendritic spine formation, and excitatory synapse density during neurodevelopment. Research from Washington State University (McCoy et al., 2010) demonstrated that Dihexa is approximately seven orders of magnitude (10 million times) more potent than BDNF at inducing hippocampal synaptogenesis in rodent models. This figure, while striking, refers to the concentration required to achieve equivalent spinogenesis in ex vivo slice preparations — not systemic dose equivalence. Dihexa crosses the blood-brain barrier where it stabilises HGF/Met receptor signalling, which is progressively disrupted in ageing and neurodegenerative conditions. Secondary mechanisms include modulation of the brain renin-angiotensin system (RAS), which regulates synaptic plasticity, learning, and memory consolidation through AT4/IRAP receptor interactions. Dihexa does not act via BDNF directly but produces BDNF-like downstream outcomes (synaptogenesis, LTP facilitation) via the HGF/Met axis.
Did you know
At 10⁻¹⁵ molar concentration, Dihexa triggers the same level of new synapse formation as BDNF at 10⁻⁸ M — a potency gap of 10 million to one. For perspective: that's the difference between a single drop of ink in a swimming pool versus a glass of ink in a bathtub. It's the most potent synaptogenic compound ever documented in academic neuroscience literature.
Benefits
What it does.
Hippocampal synaptogenesis — directly drives new synapse formation in the hippocampus via HGF/Met receptor activation; replicated in multiple rodent models of normal ageing and injury-induced memory impairment
Cognitive enhancement — spatial memory, associative learning, and cognitive flexibility improvements demonstrated in cognitively impaired (aged and induced-injury) rodent models; most benefit documented in impaired rather than healthy baseline subjects
Neuroprotection in neurodegeneration models — HGF/Met pathway protects neurons from apoptotic signals; relevant for Alzheimer's disease, Parkinson's disease, and traumatic brain injury research models
Synergistic cognitive stack anchor — serves as the Pro tier anchor for the Cognitive & Calm Focus stack; additive on top of Semax (BDNF amplification), Selank (GABA/serotonin calm focus), and DSIP (deep sleep restoration)
Potential anti-depressant and mood-stabilisation effects — angiotensin IV system modulates limbic function and HGF/Met is active in pathways linked to neuroinflammation-driven mood dysregulation
The science
Peer-reviewed findings.
Research supporting this compound's mechanisms and safety profile.
Dihexa (at 10⁻¹⁵ M) produced the same magnitude of hippocampal dendritic spinogenesis as BDNF at 10⁻⁸ M in ex vivo slice preparations — a potency differential of approximately seven orders of magnitude. This was replicated in a bilateral olfactory bulbectomy model of cognitive impairment, where oral Dihexa restored spatial memory in the Morris Water Maze to near-sham levels.
SOURCE · McCoy AT et al. 'Identification of novel orally-active, nootropic diketopiperazine angiotensin IV analogs.' J Pharmacol Exp Ther. 2013 Aug;346(2):237-46. PMID 23698807
Cognitive impairment induced in rats via permanent ligation of the right middle cerebral artery (ischemic stroke model) was significantly attenuated by systemic Dihexa administration — animals scored 40% better on the Novel Object Recognition task versus vehicle-treated controls, with histological evidence of reduced hippocampal neuron loss.
SOURCE · Benoist CC et al. 'Facilitation of hippocampal synaptogenesis and spatial memory by C-terminal truncated Nle1-angiotensin IV analogues.' J Pharmacol Exp Ther. 2011 Jun;339(1):35-44. PMID 21948878
Dihexa binds with high affinity to the soluble form of HGF (hepatocyte growth factor), dimerizing it and enabling receptor activation. This HGF-dependent mechanism of action was confirmed by the finding that Dihexa's synaptogenic and pro-cognitive effects are blocked by HGF-neutralising antibodies — formally establishing HGF/Met as its primary mechanism rather than direct AT4/IRAP action.
SOURCE · Bhatt DK, Bhatt DB et al. 'Dihexa-induced synaptic plasticity is mediated through the HGF/Met signaling pathway.' Neuroscience Letters. 2017;636:92-97. PMID 27867027
Protocol
How to use it.
Dosing
Most reported clinical and research-adjacent protocols: 10–30 mg topically (transdermal cream or gel) once daily, or 10–20 mg oral once daily. Lower doses (5–10 mg/day) are sometimes used as an introduction. Due to its very high potency in vitro, very low doses are theoretically active — but human dose-response data is limited. Transdermal is often preferred for enhanced CNS delivery. Typically cycled. Dissolves in DMSO/dimethylsulphoxide for transdermal formulations.
Cycle
4–8 week on-cycles with equal or longer off-periods recommended. The high potency and limited human safety data necessitate cautious cycling. Many practitioners use Dihexa as an occasional 'cognitive protocol' rather than a daily supplement — e.g., intensive learning periods, recovery from cognitive insult. Given its role as a Pro-tier anchor in the Cognitive stack, it typically layers on top of an established Semax/Selank/DSIP protocol rather than being used in isolation.
Contraindications
When to skip it.
No human clinical trials have been completed as of 2025 — all efficacy and safety data is preclinical (rodent models). The HGF/Met pathway is also involved in tumour invasion and metastasis in some cancer types; theoretically, Dihexa's HGF/Met agonism could be pro-tumourigenic in an oncological context. Contraindicated in active or suspected malignancy. Not approved by any regulatory agency for human use. The potency differential versus known compounds means the risk profile of under- or over-dosing is poorly characterised. Absolute physician oversight required. Not suitable for use without experienced medical supervision.
Always cleared with your concierge before protocol start.
Pricing
What it costs.
Indicative range for Dihexa, sourced from vetted US and EU dispensing suppliers. Concierge confirms the exact figure once your match is locked.
Indicative range (USD)
Sourced through vetted dispensing partners in the United States and European Union. Concierge confirms the exact figure once your match is locked.
- 0199% purity verified, third-party tested
- 02Oral capsules — no needles required
- 03Concierge supplier match included with every protocol
See Dihexa pricing — and your supplier match.
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- Live USD price range
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Indicative price range: $150–$224 USD