Semax vs Dihexa: Cognitive Enhancement Peptide Comparison | Peptpedia
This comprehensive analysis compares Semax and Dihexa based on peer-reviewed clinical research, examining their mechanisms of action, efficacy data, and safety profiles. For complete individual peptide profiles, visit the dedicated research pages linked above.
Semax and Dihexa are two of the most potent cognitive-enhancing peptides in preclinical research, though through entirely different mechanisms. Semax is an ACTH(4-7) analog registered in Russia that stimulates BDNF and NGF production; Dihexa is a small peptide with 10^7-fold greater potency than HGF at the MET receptor, driving synaptogenesis. Both have intriguing preclinical profiles but very limited human clinical data.
Chemical Identity
Side-by-Side Comparison
| Property | Semax | Dihexa |
|---|---|---|
| Mechanism | BDNF/NGF upregulation via ACTH-like activity | HGF/MET receptor agonism (synaptogenesis) |
| Length | 7 amino acids (heptapeptide) | 5 amino acids (pentapeptide + modification) |
| Potency vs Natural Ligand | Comparable to ACTH 1-24 | 10^7-fold more potent than HGF at MET |
| Registration | Registered medicine in Russia | Preclinical research compound only |
| Primary Effect | Neuroprotection, BDNF elevation, cognition | Synaptogenesis, cognitive reversal in aged animals |
| Administration | Intranasal (nasal drops) | Oral, transdermal (research) |
Mechanism of Action: BDNF vs Synaptogenesis
Semax (Met-Glu-His-Phe-Pro-Gly-Pro) is a stabilized analog of ACTH(4-7) developed at the Institute of Molecular Genetics in Moscow. It stimulates the synthesis and release of brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF) in hippocampal and cortical neurons, supporting neuronal survival, synaptic plasticity, and long-term potentiation. It also modulates the serotonin and dopamine systems through ACTH receptor interactions.
Dihexa is a modified angiotensin IV analog identified by Joseph Harding's group at Washington State University. It binds hepatocyte growth factor (HGF) and its receptor MET with extraordinarily high affinity—approximately 10 million times more potently than HGF itself. MET receptor activation in the brain promotes dendritic spine formation (synaptogenesis) and has been shown to reverse cognitive deficits in aged and cognitively impaired animals.
Frequently Asked Questions
Research Citations
Semax, an ACTH 4-10 analogue with nootropic properties, activates dopaminergic and serotoninergic brain systems in rodents
Eremin KO, Kudrin VS, Saransaari P, et al. (2005). Neurochemical Research