Overview

Semax is a synthetic heptapeptide composed of the Met-Glu-His-Phe fragment of adrenocorticotropic hormone (ACTH residues 4–7) extended with a C-terminal Pro-Gly-Pro sequence that dramatically extends plasma stability without preserving the melanocortin/steroidogenic activity of the parent hormone. It was developed at Moscow State University and the V. V. Zakusov Institute of Pharmacology and is registered in Russia for a stroke and cognitive-decline indication. Elsewhere it is available only as a research peptide.

Mechanism (as reported in the literature)

  • BDNF and NGF upregulation. Multiple rat studies report rapid and sustained upregulation of brain-derived neurotrophic factor and nerve growth factor transcription after intranasal administration.
  • Dopaminergic and serotonergic modulation. Research indicates increases in striatal dopamine turnover and modulation of the serotonergic system.
  • Neuroprotection in ischemia models. Animal studies of middle-cerebral-artery occlusion report reductions in infarct volume and functional deficit scores with peri-event Semax administration.
  • Melanocortin-independent action. Studies indicate the truncation of the ACTH(4-10) fragment to Semax retains neurotrophic activity while eliminating adrenal-steroidogenic activity.

Research findings

  • Ischemic-stroke clinical work. Russian multicentre trials reported improvements in functional-outcome scores at 30 days when Semax was administered within the first 24 hours after ischemic stroke (Gusev et al., 2005).
  • Cognitive-performance animal studies. Passive-avoidance and Morris water-maze studies report improved acquisition and retention scores at intranasal doses of 50 μg/kg.
  • Transcriptomic response. Rat hippocampal gene-expression studies report broad changes in immediate-early gene and neurotrophin-pathway transcription within hours of a single dose (Medvedeva et al., 2013; PMID 23705496).

Common dosing (from published research protocols)

Russian clinical protocols describe intranasal administration of 200–1,200 mcg per day. Cognitive-research protocols in community writeups commonly report 200–600 mcg per intranasal administration, one or two times daily.

Reconstitution

A 5 mg vial reconstituted with 2 mL of bacteriostatic water yields a 2,500 mcg/mL solution — the concentration is typically transferred to a nasal-dropper applicator for research use.

  • 200 mcg = 0.08 mL = 8 units on a U-100 syringe
  • 600 mcg = 0.24 mL = 24 units

Storage

Reconstituted Semax is refrigerated at 2–8 °C and reported as stable for approximately 30 days.

  • Selank — the anxiolytic peptide from the same Russian institute.

Common stacks

References

  • Medvedeva, E. V., et al. (2013). “The peptide Semax affects the expression of genes involved in the immune and vascular response in the ischemic rat brain.” Molecular Biology, 47(1). PMID 23705496.
  • Gusev, E. I., et al. (2005). “Efficacy of Semax in acute period of hemispheric ischemic stroke.” Zhurnal Nevrologii i Psikhiatrii Imeni S.S. Korsakova, 105(3).
  • Ashmarin, I. P., et al. (2005). “Design and study of peptide drugs based on adrenocorticotropic hormone fragments.” Bulletin of Experimental Biology and Medicine, 140(4). PMID 16690555.