Semax — Complete Research Guide (2026)
Last updated 2026-06-25
TL;DR
A synthetic peptide derived from adrenocorticotropic hormone fragment (4-10), studied in Russia for neuroprotective and cognitive effects.
What is Semax?
Semax is a synthetic heptapeptide (Met-Glu-His-Phe-Pro-Gly-Pro) based on the ACTH(4-10) fragment, extended with Pro-Gly-Pro to improve stability and remove hormonal (adrenal-stimulating) activity.
It is registered and used clinically in Russia (typically intranasally) for stroke and cognitive indications, but it is NOT approved by the FDA or EMA, and the most rigorous literature is Russian.
The mechanistic evidence is mostly preclinical (rat) work on neurotrophins, with a smaller set of Russian clinical studies of variable methodological rigor.
How does Semax work?
Semax rapidly increases expression of brain-derived neurotrophic factor (BDNF) and nerve growth factor and their receptors in the rodent brain, and modulates monoaminergic signaling.
It appears to act via specific membrane binding sites, promoting neurotrophin transcription rather than acting as a classical receptor agonist. [INFOGRAPHIC: Semax BDNF up-regulation in the brain]
What does the research say about Semax?
- A single dose of Semax increased BDNF protein across multiple rat brain regions in vivo, the proposed basis for its neurotrophic effects. [1]
- In an open clinical study of acute hemispheric ischemic stroke, Semax (12-18 mg/day) was associated with improved recovery of neurological deficits. [6]
- After experimental cerebral ischemia in rats, Semax increased transcription of neurotrophins and their receptor genes in the brain cortex. [3]
Clinical research & studies
The references below are the primary sources cited throughout this guide. Each links directly to PubMed or the regulator. Where evidence is preclinical (animal or in-vitro), that is stated rather than implied.
- [1] The heptapeptide SEMAX stimulates BDNF expression in different areas of the rat brain in vivo — Dolotov OV, Karpenko EA, Inozemtseva LS et al., Dokl Biol Sci 2003. (animal (rat))
- [2] Semax, an analogue of adrenocorticotropin (4-10), binds specifically and increases levels of brain-derived neurotrophic factor protein in rat basal forebrain — Dolotov OV, Karpenko EA, Seredenina TS et al., J Neurochem 2006. (animal (rat))
- [3] Semax and Pro-Gly-Pro activate the transcription of neurotrophins and their receptor genes after cerebral ischemia — Dmitrieva VG, Povarova OV, Skvortsova VI et al., Cell Mol Neurobiol 2010. (animal (rat))
- [4] Effect of the heptapeptide Semax on the human electroencephalogram — Koroleva MV et al., Biull Eksp Biol Med 1996. (human (EEG))
- [5] Semax, an analogue of adrenocorticotropin (4-10), is a potential agent for the treatment of attention-deficit hyperactivity disorder and Rett syndrome — Tsai SJ, Med Hypotheses 2007. (review/hypothesis)
- [6] Effectiveness of semax in acute period of hemispheric ischemic stroke (a clinical and electrophysiological study) — Gusev EI, Skvortsova VI, Miasoedov NF et al., Zh Nevrol Psikhiatr Im S S Korsakova 1997. (human clinical (stroke, ~30 treated vs 80 control))
Dosing context
Russian clinical stroke studies described intranasal doses in the range of roughly 12-18 mg/day, while most mechanistic data derive from rodent dosing; these describe study conditions, not a usage recommendation.
No dose has been validated by Western regulators, and the peptide is discussed here strictly in a research context.
Side effects & safety profile
Semax has decades of clinical use in Russia (mainly intranasal) with a reportedly favorable tolerability profile in Russian studies, but it has never undergone FDA/EMA safety review.
Independent Western safety data, long-term safety studies, and reliable published human pharmacokinetic parameters (including half-life) are lacking, so any specific half-life claim would be speculative.
Because most controlled data are preclinical or from Russian trials with small samples, the safety picture outside that context is not well characterized.
Stacking & combinations
Some rodent work studied Semax alongside its metabolite Pro-Gly-Pro, but there are no controlled human studies of Semax combined with other nootropics or drugs, so combination effects are unproven.
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Frequently asked questions
No. Semax is registered and used in Russia but is not approved by the FDA or EMA, and the strongest literature is in Russian journals.
References
- [1] The heptapeptide SEMAX stimulates BDNF expression in different areas of the rat brain in vivo — Dolotov OV, Karpenko EA, Inozemtseva LS et al., Dokl Biol Sci 2003. PMID: 14556513. View sourceStudy: animal (rat)Semax increased BDNF expression across several rat brain regions after administration.
- [2] Semax, an analogue of adrenocorticotropin (4-10), binds specifically and increases levels of brain-derived neurotrophic factor protein in rat basal forebrain — Dolotov OV, Karpenko EA, Seredenina TS et al., J Neurochem 2006. PMID: 16635254. View sourceStudy: animal (rat)Intranasal Semax raised BDNF in the basal forebrain within ~3 h via specific binding sites.
- [3] Semax and Pro-Gly-Pro activate the transcription of neurotrophins and their receptor genes after cerebral ischemia — Dmitrieva VG, Povarova OV, Skvortsova VI et al., Cell Mol Neurobiol 2010. PMID: 19633950. View sourceStudy: animal (rat)Semax increased neurotrophin and receptor gene transcription in rat cortex after ischemia.
- [4] Effect of the heptapeptide Semax on the human electroencephalogram — Koroleva MV et al., Biull Eksp Biol Med 1996. PMID: 8679991. View sourceStudy: human (EEG)Semax altered human EEG activity, an early human pharmacodynamic observation.
- [5] Semax, an analogue of adrenocorticotropin (4-10), is a potential agent for the treatment of attention-deficit hyperactivity disorder and Rett syndrome — Tsai SJ, Med Hypotheses 2007. PMID: 16996699. View sourceStudy: review/hypothesisHypothesizes Semax could aid ADHD/Rett via dopaminergic and BDNF effects (speculative, no trial data).
- [6] Effectiveness of semax in acute period of hemispheric ischemic stroke (a clinical and electrophysiological study) — Gusev EI, Skvortsova VI, Miasoedov NF et al., Zh Nevrol Psikhiatr Im S S Korsakova 1997. PMID: 11517472. View sourceStudy: human clinical (stroke, ~30 treated vs 80 control)Semax was associated with improved recovery of neurological deficit in acute ischemic stroke.