Home › Compare › Semax vs Selank

Semax vs Selank

Side-by-side comparison of Semax, Selank — mechanism, dosing, half-life, side effects, and research status.

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Attribute Semax Semax (Heptapeptide ACTH Analogue) Cognitive Selank Selank (Tuftsin Analogue Heptapeptide) Cognitive
Basics
Molecular type ACTH-Derived NeuropeptideAnxiolytic Neuropeptide
Amino acids 77
Molecular weight 813.9 Da751.9 Da
Half-life ~minutes (nasal); longer CNS retention~minutes (nasal); prolonged CNS effect
Route(s) Intranasal, SubcutaneousIntranasal, Subcutaneous
Mechanism & Research
Primary mechanism Semax's primary mechanism involves upregulation of brain-derived neurotrophic factor (BDNF) — a neurotrophin critical for neuronal survival, synaptic plasticity, and neurogenesis. In animal models, Semax increases BDNF m… Selank modulates GABA-A receptor function via an allosteric mechanism distinct from benzodiazepines, producing anxiolytic effects without sedation or tolerance development. It also enhances GABA receptor sensitivity with…
Research status Research Compound Research Compound
Evidence summary Semax has been investigated in Russian clinical research since the 1980s. It has been approved in Russia as a drug for stroke, TBI, and cognitive decline. Western research interest has grown, but large RCTs meeting curre… Selank is approved in Russia for anxiety disorders and cognitive enhancement. Clinical studies demonstrate anxiolytic efficacy without dependence in generalised anxiety disorder. Western research is emerging.
Protocol & Dosing
Typical dose 200–600 mcg/day (intranasal)250–500 mcg/day (intranasal)
Frequency 1–2x daily1–2x daily
Duration 2–4 weeks cycles2–4 weeks
Timing Morning (or morning + midday); avoid evening to prevent sleep disruptionMorning and/or before stressful activities
Safety
Common side effects
  • Nasal irritation
  • Mild stimulation/anxiety (dose-dependent)
  • Headache (initial)
  • Temporary appetite change
  • Mild nasal irritation
  • Slight drowsiness (rare, dose-dependent)
  • Mood changes (initial adjustment)
Contraindications
  • Active psychiatric conditions (bipolar, schizophrenia)
  • Epilepsy/seizure disorders
  • Pregnancy
  • Severe psychiatric disorders requiring medication management
  • Pregnancy (insufficient data)
  • Known peptide hypersensitivity
Anti-doping Not Prohibited Not Prohibited
Deeper reading
Related peptides Selank, Dihexa, P21 Semax, P21, DSIP
Full profile Read full Semax profile → Read full Selank profile →

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Comparison data is compiled from each peptide’s individual profile. All values are drawn from peer-reviewed research and regulatory sources. For educational use only — not medical advice. Verify any protocol with a qualified healthcare provider.