Cognitive & neuro
Dihexa
A synaptogenic peptide with striking rodent results and zero human data — one of the least evidenced compounds sold as a nootropic.
What it is
Dihexa is a small modified peptide derived from angiotensin IV, designed to enter the brain easily. In rodent and cell studies it promotes the formation of new synapses and improves learning, which has made it popular in nootropic circles. There are no human trials, no pharmacokinetic data, and it is not approved for any use.
How it works
- 1
A modified dipeptide designed to cross the blood-brain barrier more readily than natural peptides.
- 2
In cell studies it activates the HGF/c-Met pathway, which is involved in synapse formation.
- 3
Rodent studies report new synapses and improved learning after dosing.
- 4
It is far more potent than BDNF in laboratory comparisons, which is the source of most of its reputation.
- 5
None of this has been reproduced in humans, and the growth-factor pathway it activates is also implicated in cancer.
What it's studied for
Reported and studied effects
- Improved memory and learning in rodent studies
- New synapse formation in cell cultures
- Reported cognitive improvements in user accounts
- No measured human effect
Research protocol notes
Research context onlyResearch context only — no human protocol exists and no human pharmacokinetic data have been published. Rodent studies used very small doses in the microgram-per-kilogram range. Schedules circulating online are guesses extrapolated from animals, which is a notoriously unreliable way to set a human dose.
These figures are described so you can understand what researchers did. They are not a dose, a schedule, or a suggestion — and they are not a substitute for a doctor.
Possible side effects and contraindications
Safety profile
Possible side effects
- Not studied in humans
- Theoretical cancer risk from growth-factor pathway activation
- Unknown effects on blood pressure and the liver
- Injection-site reactions
Contraindications and cautions
- Not established
- Pregnancy, breastfeeding and childhood
- Any cancer history — the peptide promotes cell growth
- Neurological conditions without medical advice
A side-effect list is never complete, and these are not the only situations that warrant caution. Anything unexpected, or anything you are unsure about, should be discussed with a doctor before use.
Evidence assessment
All published evidence comes from rodents and cell cultures; there are no human trials of any kind.
References
References link to published literature, regulator pages or literature indexes. Where a link points to a search, it collects the peer-reviewed work on that molecule rather than a single study.
Related
Related peptides
Other entries in Cognitive & neuro.
Cognitive & neuro
ACTH 4-10 (Org 2766)
The nerve-acting fragment of ACTH, developed as a drug candidate for nerve damage and cognitive decline, and abandoned.
Cognitive & neuro
BDNF (brain-derived neurotrophic factor)
The brain's main growth factor for plasticity: essential, widely measured, and not something a supplement can deliver.
Cognitive & neuro
Cerebrolysin
A porcine brain peptide mixture licensed in parts of Eastern Europe and Asia for stroke and dementia, without EMA or FDA approval.