Semax
Semax (Heptapeptide ACTH Analogue)
Semax is a synthetic heptapeptide analogue of ACTH(4-7), developed in Russia and approved there for clinical use in stroke and cognitive decline. It is studied for BDNF upregulation, neuroprotection, cognitive enhancement, and stroke recovery. Intranasal delivery allows direct nose-to-brain transport, bypassing the blood-brain barrier.
Mechanism of Action
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 mRNA expression in the cortex and hippocampus within hours of administration.
Semax also modulates the serotonergic and dopaminergic systems, which partially explains its reported effects on mood, motivation, and stress resilience. Animal studies demonstrate reduced anxiety-like behaviour and enhanced spatial memory in rodent cognition models.
Intranasal Semax reaches CNS tissue via olfactory nerve transport and direct mucosal absorption. Despite a short plasma half-life, CNS retention is prolonged — contributing to effects lasting several hours beyond the initial absorption window.
Research Evidence
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 current Western regulatory standards are limited.
Semax Increases BDNF Expression and Protects Against Ischaemic Brain Injury
Intranasal Semax significantly elevated BDNF mRNA in rat cerebral cortex and reduced infarct volume in a thread-occlusion ischaemia model, confirming neuroprotective mechanism via neurotrophic pathway upregulation.
Clinical Efficacy of Semax in Acute Ischaemic Stroke
Randomised trial in acute stroke patients showed Semax intranasal significantly improved neurological recovery scores versus placebo at 10-day and 6-month follow-ups, with favourable tolerability profile.
Typical Research Protocol
N-Acetyl Semax (NA-Semax) is a stabilised form with improved potency and bioavailability. Cycles are typically kept short (2–4 weeks) with 2-week breaks to prevent adaptation.
Safety Profile
Reported Side Effects
- Nasal irritation
- Mild stimulation/anxiety (dose-dependent)
- Headache (initial)
- Temporary appetite change
Contraindications
- Active psychiatric conditions (bipolar, schizophrenia)
- Epilepsy/seizure disorders
- Pregnancy
- Known ACTH pathway hypersensitivity
Common Research Stacks
Frequently Asked Questions
Is Semax legal?
Semax is not scheduled as a controlled substance in most Western countries and is not on the FDA's list of approved or prohibited drugs. It exists in a legal grey area — not approved for human use, not explicitly prohibited. It is approved and registered as a pharmaceutical drug in Russia. Verify current status in your jurisdiction before obtaining.
What does Semax feel like?
User reports (informal) commonly describe increased mental clarity, motivation, and processing speed within 30–60 minutes of intranasal administration. Some note mild stimulatory effects similar to low-dose caffeine. Effects tend to be subtle and cumulative rather than immediately dramatic — most notable cognitive benefits emerge after 5–10 days of consistent use.
What is the difference between Semax and NA-Semax?
NA-Semax (N-Acetyl Semax) is an acetylated form of Semax with improved lipophilicity, stability in nasal mucosa, and greater potency. The N-acetyl modification increases CNS penetration via the olfactory route. NA-Semax Amidate is a further modification combining acetylation and C-terminal amidation for maximum stability and potency. Lower doses of NA-Semax (100–200 mcg) are typically used compared to standard Semax (400–600 mcg).
Can Semax be used for ADHD or focus disorders?
Semax's BDNF upregulation and dopaminergic modulation make it of research interest for attention and executive function. Informal reports describe improved focus and reduced mental fatigue that some find relevant to ADHD symptoms. However, there are no controlled trials in ADHD populations specifically, and it should not be considered a replacement for evidence-based ADHD treatments.
How should Semax be stored?
Reconstituted Semax nasal spray should be stored refrigerated (2–8°C) and used within 4–6 weeks. Lyophilised powder remains stable at room temperature for months but should be refrigerated for long-term storage. Light exposure degrades the peptide — use dark or amber glass vials and minimise UV exposure during handling.
Key Research References
- Mendzheritsky AM et al. (2001). Neuroprotective effects of Semax in cerebral ischaemia. Neurosci Lett.
- Kaplan AY et al. (1996). Semax effects on EEG activity in humans. Neurosci Behav Physiol.
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