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Dihexa
A hexapeptide analogue of angiotensin IV developed at Washington State University that is 10 million times more potent than BDNF at promoting synaptogenesis - crossing the blood-brain barrier orally and reversing cognitive deficits in aged animal models through dramatic increases in dendritic spine density.
Benefits
What is Dihexa?
Dihexa (N-hexanoic-Tyr-Ile-(6)aminohexanoic amide) is a synthetic hexapeptide derived from the hepatocyte growth factor (HGF) system, originally developed by Dr. Joseph Harding and colleagues at Washington State University. First described in a 2013 paper published in the Journal of Pharmacology and Experimental Therapeutics, dihexa was designed as a stable, orally bioavailable analogue of angiotensin IV that activates the HGF/c-Met receptor system. The most striking finding from the initial research was that dihexa promotes new synapse formation at concentrations approximately 10 million times lower than BDNF, operating at picomolar levels - making it one of the most potent procognitive compounds ever identified in preclinical research.
In aged rats with scopolamine-induced cognitive deficits, dihexa fully restored performance on the Morris water maze spatial memory task when administered either intracerebroventricularly or orally. The compound increased dendritic spine density and promoted the formation of new functional synaptic connections, effectively rejuvenating aged neural circuits. Harding's group demonstrated that dihexa acts by binding to HGF and facilitating its dimerisation, which is required for activation of the c-Met receptor tyrosine kinase. This triggers downstream signalling cascades including PI3K/Akt and MAPK/ERK pathways that promote spinogenesis, synaptogenesis, and neuronal survival. While these preclinical results are extraordinarily promising, dihexa remains firmly in the research stage with no human clinical trials completed, and its potent growth-factor activity raises legitimate theoretical concerns about potential oncogenic effects with chronic use.
- HGF/c-Met receptor activation: Dihexa binds to hepatocyte growth factor (HGF) and facilitates its dimerisation, activating the c-Met receptor tyrosine kinase and triggering procognitive signalling cascades at picomolar concentrations
- Synaptogenesis promotion: Activates PI3K/Akt and MAPK/ERK pathways downstream of c-Met, stimulating the formation of new synaptic connections between neurons at a potency approximately 10 million times greater than BDNF
- Dendritic spine proliferation: Increases dendritic spine density in hippocampal and cortical neurons, expanding the physical substrate for synaptic transmission and information storage
- Neuronal survival signalling: The HGF/c-Met axis activates anti-apoptotic pathways including Bcl-2 upregulation, protecting existing neurons from programmed cell death and age-related degeneration
- Oral bioavailability: Unlike most peptides, dihexa crosses the blood-brain barrier when administered orally, a critical advantage for practical nootropic use that stems from its engineered metabolic stability
- Animal research doses: In rat studies, effective doses ranged from 0.01 to 2 mg/kg administered orally, intranasally, or intracerebroventricularly
- Community-reported oral dose: 10-20 mg per day is the most commonly reported oral dose among early adopters in the nootropics community, though this is entirely empirical
- Intranasal use: Some users report intranasal administration at lower doses (2-5 mg) for potentially improved CNS delivery, though no human pharmacokinetic data exists
- Picomolar potency: The extraordinary potency of dihexa at the molecular level means that effective brain concentrations are achieved at relatively low oral doses
- Duration of use: Most community protocols involve short courses (2-4 weeks) followed by extended breaks, given the lack of long-term safety data and theoretical growth-factor concerns
- No human safety data: Dihexa has never been tested in human clinical trials. All safety information is extrapolated from animal studies and anecdotal community reports
- Theoretical cancer risk: The HGF/c-Met pathway is frequently overactivated in various cancers. Chronic exogenous activation of this growth factor system could theoretically promote tumour growth or accelerate existing malignancies - this is the most serious concern
- Unknown long-term effects: The consequences of sustained exogenous synaptogenesis and growth factor stimulation in the human brain are completely unknown. Excessive synapse formation could theoretically disrupt established neural circuits
- Purity concerns: As an unregulated research peptide, quality control varies dramatically between sources. Impurities in peptide synthesis could pose additional risks
- Not recommended for individuals with: Any history of cancer, family history of cancer, or conditions involving abnormal cell growth. The growth-promoting mechanism makes this a critical contraindication
Natural Sources & Forms
- Research peptide vendors: Available from specialist peptide synthesis companies as a lyophilised powder requiring reconstitution
- Capsule form: Some nootropic vendors offer pre-dosed capsules, though the peptide's stability in this format may be questionable
- No pharmaceutical production: Dihexa is not manufactured by any pharmaceutical company and remains exclusively a research compound
- Storage requirements: As a peptide, dihexa should be stored in a cool, dry environment. Reconstituted solutions should be refrigerated and used within a defined timeframe
Frequently Asked Questions
A hexapeptide analogue of angiotensin IV developed at Washington State University that is 10 million times more potent than BDNF at promoting synaptogenesis - crossing the blood-brain barrier orally and reversing cognitive deficits in aged animal models through dramatic increases in dendritic spine density.
The key benefits of Dihexa include: Cognitive Enhancement, Creativity, Focus, Longevity, Memory.
HGF/c-Met receptor activation: Dihexa binds to hepatocyte growth factor (HGF) and facilitates its dimerisation, activating the c-Met receptor tyrosine kinase and triggering procognitive signalling cascades at picomolar concentrations Synaptogenesis promotion: Activates PI3K/Akt and MAPK/ERK pathways downstream of c-Met, stimulating the formation of new synaptic connections between neurons at a potency approximately 10 million times greater than BDNF Dendritic spine proliferation: Increases dendritic spine density in hippocampal and cortical neurons, expanding the physical substrate for synaptic transmission and information storage Neuronal survival signalling: The HGF/c-Met axis activates anti-apoptotic pathways including Bcl-2 upregulation, protecting existing neurons from programmed cell death and age-related degeneration Oral bioavailability: Unlike most peptides, dihexa crosses the blood-brain barrier when administered orally, a critical advantage for practical nootropic use that stems from its engineered metabolic stability
Animal research doses: In rat studies, effective doses ranged from 0.01 to 2 mg/kg administered orally, intranasally, or intracerebroventricularly Community-reported oral dose: 10-20 mg per day is the most commonly reported oral dose among early adopters in the nootropics community, though this is entirely empirical Intranasal use: Some users report intranasal administration at lower doses (2-5 mg) for potentially improved CNS delivery, though no human pharmacokinetic data exists Picomolar potency: The extraordinary potency of dihexa at the molecular level means that effective brain concentrations are achieved at relatively low oral doses Duration of use: Most community protocols involve short courses (2-4 weeks) followed by extended breaks, given the lack of long-term safety data and theoretical growth-factor concerns
No human safety data: Dihexa has never been tested in human clinical trials. All safety information is extrapolated from animal studies and anecdotal community reports Theoretical cancer risk: The HGF/c-Met pathway is frequently overactivated in various cancers. Chronic exogenous activation of this growth factor system could theoretically promote tumour growth or accelerate existing malignancies - this is the most serious concern Unknown long-term effects: The consequences of sustained exogenous synaptogenesis and growth factor stimulation in the human brain are completely unknown. Excessive synapse formation could theoretically disrupt established neural circuits Purity concerns: As an unregulated research peptide, quality control varies dramatically between sources. Impurities in peptide synthesis could pose additional risks Not recommended for individuals with: Any history of cancer, family history of cancer, or conditions involving abnormal cell growth. The growth-promoting mechanism makes this a critical contraindication
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