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PreclinicalResearch compoundModerate evidence

Semax

Russian Rx heptapeptide (ACTH 4-10 analog). Stroke rehab + cognitive enhancement, intranasal spray.

NootropicPeptidePeptideNasalFocusNeuroprotectionMood SupportBDNFBDNFDopamineSerotonin

Pharmacology

ClassPeptide · Nasal · Focus · Neuroprotection · Mood Support · BDNF
Primary targetBDNF / TrkB upregulation
Targets4 receptor targets
Half-life20-30 min
Onset10-15 min
EvidenceModerate evidence
Affected systemsBDNFDopamineSerotonin

Contents

Related comparisons

Semax vs Selank

WHAT IS SEMAX?

Detailed overview

Semax is a Met-Glu-His-Phe-Pro-Gly-Pro heptapeptide, a synthetic analog of the 4-10 fragment of adrenocorticotropic hormone (ACTH), with BDNF-mimicking action. It is Rx in Russia as an intranasal spray for acute ischemic stroke, post-stroke rehabilitation, and transient ischemic attack (TIA). It exhibits a dopaminergic + serotonergic + neurotrophic + nootropic profile. Intranasal administration allows it to cross the blood-brain barrier and act centrally. Note: this entry also appears in the peptide library with different framing (peptide-focus vs nootropic-focus).

Mechanism

ACTH(4-10) heptapeptide, BDNF-mimicking

Half-life

20-30 min (intranasal)

Onset

10-15 min

Legal status

Russia Rx, EU/USA research

Receptor profile

  • BDNF / TrkBStrong
  • MC4R (melanocortin)Moderate
  • Prolyl endopeptidaseModerate
  • Dopamine / serotoninModerate

Safety

Side effects, stop signs, contraindications

Side effects · 6

  • Nasal mucosa irritation, stinging or dryness at the intranasal application site
  • Headache, especially at higher doses
  • Overstimulation, irritability or restlessness (raised dopaminergic/serotonergic tone)
  • Disrupted sleep if taken in the late afternoon or evening
  • Transient blood-pressure rise in sensitive individuals (ACTH-fragment analog nature)
  • Anecdotal hair thinning/shedding reports (presumed BDNF hair-follicle-cycle effect, not clinically confirmed)

Contraindications · 6

  • Pregnancy and breastfeeding (peptide-specific human safety data lacking)
  • Avoid combining with MAO inhibitors (risk of serotonergic potentiation)
  • Active schizophrenia, mania or bipolar spectrum (dopaminergic overstimulation, mania-trigger risk)
  • Caution and clinical monitoring with SSRIs/SNRIs or stimulants (additive serotonergic/stimulant effect)
  • Known hypersensitivity to Semax or ACTH-fragment analogs
  • Melanocortin-receptor-sensitive tumors, e.g. active melanoma (theoretical, due to ACTH-analog nature)

Related Nootropics

Same therapeutic category

Studies

Related research and clinical findings

FAQ

FAQ

Semax is a nasal spray approved as a prescription medicine in Russia, used mainly to protect the brain and aid rehabilitation after a stroke, as well as for a short-term boost to attention and memory. It is also credited with mild stress- and anxiety-reducing effects. It is an established medical treatment in Russia, but it is not an approved drug in Western countries.

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Structure & chemistry

TypeNootropic
FormulaC37H51N9O10S
UpdatedJune 19, 2026
MolekulaX Editorial Team·Source-verified · PubMed · FDA · EMA
Updated: June 19, 2026

The information here is strictly for educational and scientific purposes. It does not replace medical advice or clinical consultation, and it does not encourage illegal substance or pharmaceutical use. Data is sourced. When in doubt, consult your doctor.