Semax
A stabilised fragment of ACTH with the hormonal activity removed, registered in Russia for stroke and cognitive indications. Evidence is almost entirely Russian.
Cognitive & Neuro
Dihexa
A synthetic angiotensin IV derivative reported to promote new synapse formation in rodents. No human data of any kind exists.
Overview
Hepatocyte growth factor is a signal that, in the brain, encourages neurons to grow new connections. Dihexa is thought to make neurons more sensitive to it rather than acting on its own — it appears to help HGF bind and activate its receptor more effectively. In rats with chemically induced cognitive impairment, it restored performance on learning tasks at very small doses, including orally. That is the whole evidence base: rodents, from a small number of laboratories.
A small angiotensin IV analogue designed for blood-brain barrier penetration and metabolic stability. Proposed to act as a positive modulator of hepatocyte growth factor binding to its receptor tyrosine kinase c-Met, potentiating HGF-dependent dendritic arborisation and synaptogenesis in hippocampal neurons. Reported effective in scopolamine-induced and lesion models of cognitive deficit in rats at microgram-per-kilogram doses with oral activity. Nothing has progressed to a registered human trial, and the c-Met pathway is oncogenically relevant, which is the principal unaddressed safety question.
Research areas
SynaptogenesisCognitive impairmentHGF/c-Met signalling
Dosing reported in the literature
Every protocol below is reproduced from a published study or approved labelling, with its source named. These are records of what was studied — not recommendations, and not a suggestion that any of them is appropriate for any person.
| Protocol as reported | Source |
|---|---|
| Oral dihexa at microgram-per-kilogram doses in scopolamine-impaired rats, with Morris water maze endpointsRodent only. No human equivalent dose can be derived from this. | McCoy et al., Journal of Pharmacology and Experimental Therapeutics 2013 |
Trial status
No human trials. All published efficacy data is preclinical.
Reported safety signals
- No human safety data exists at any dose.
- c-Met signalling is a well-established oncogenic pathway; a compound that potentiates it systemically has an unquantified cancer risk that no study has addressed.
- Sold entirely through unregulated channels with no verification of identity or purity.
Common questions
Is dihexa safe to take?
Nobody knows, because no human has taken it in a study that measured anything. The specific concern that deserves attention is that its proposed mechanism potentiates c-Met signalling, which is a pathway heavily implicated in tumour growth.
Primary sources
Medical disclaimer
This page is for informational and research purposes only. Nothing here constitutes medical advice. The compounds discussed are research chemicals. Consult a qualified clinician before starting any protocol.
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