Semax: research overview

Semax (ACTH 4-10 analog with PGP) is reported to raise BDNF protein and TrkB phosphorylation in rat hippocampus and basal forebrain after intranasal dosing (Dolotov et al., J Neurochem 2006; Dokl Biol Sci 2003), and to increase BDNF and NGF gene expression across multiple brain regions (Agapova et al., Neurosci Lett 2007; Shadrina et al., J Mol Neurosci 2010). Dietary omega-3 fatty acids have been reported to normalise BDNF levels and rescue learning after traumatic brain injury in rats (Wu et al., J Neurotrauma 2004), and a 2023 meta-regression of human trials reported a statistically significant rise in serum BDNF with omega-3 supplementation, more pronounced beyond 10 weeks (Sohouli et al., Clin Nutr ESPEN 2023). The two converge on raising and maintaining BDNF tone; long-chain omega-3 is the most-replicated nutritional input to that endpoint.

Semax is reported to activate transcription of BDNF, NGF, and their receptors in models of cerebral ischaemia (Dolotov et al., 2006; Agapova et al., 2007) and is used clinically in Russia in acute and subacute stroke care. Citicoline is the choline donor with the largest body of human cognitive and neuroprotection data; a 2023 systematic review and meta-analysis of seven studies in patients with mild cognitive impairment, Alzheimer's disease, or post-stroke dementia reported a positive effect on cognitive status, with pooled standardised mean differences of 0.56 to 1.57 (Bonvicini et al., Nutrients 2023). Citicoline supplies the choline required for acetylcholine synthesis and phosphatidylcholine membrane repair, occupying a complementary node to the BDNF/TrkB axis Semax engages.

Semax has been reported to modulate dopaminergic and serotoninergic neurotransmission in rodents and to raise BDNF and NGF gene expression in cortex, hippocampus, and brainstem (Shadrina et al., J Mol Neurosci 2010; Agapova et al., Neurosci Lett 2007). Pyridoxal-5-phosphate is the obligate cofactor for aromatic L-amino-acid decarboxylase, the enzyme that converts L-DOPA to dopamine and 5-HTP to serotonin, and for several GABA- and glutamate-related transaminases. The mechanistic argument is that BDNF-driven plasticity changes require a downstream neurotransmitter pool that depends on adequate P5P status. No co-administration trial of Semax with B6 has been published; the rationale is biochemical rather than empirical.