Overview
N-Acetyl Semax is an acetylated derivative of Semax, a synthetic heptapeptide analogue of the ACTH(4-10) fragment developed in Russia. The N-terminal acetylation modification confers greater proteolytic stability compared to unmodified Semax, extending the effective duration of action and enhancing CNS bioavailability following intranasal administration. It occupies an intermediate potency position between standard Semax and the more stable N-Acetyl Semax Amidate, and is used as a nootropic, neuroprotective, and neurorestorative research compound.
Mechanism of action
N-Acetyl Semax's mechanism of action involves multiple parallel pathways. It rapidly elevates brain-derived neurotrophic factor (BDNF) and its receptor TrkB in the hippocampus, supporting neuroplasticity and long-term potentiation. It activates serotonergic and dopaminergic neurotransmitter systems, contributing to mood stabilization and motivational tone. Interactions with melanocortin receptors (MC1R, MC4R) are proposed based on its ACTH peptide origin. Additionally, Semax inhibits enkephalinase enzymes that degrade endogenous neuropeptides, prolonging their activity. Intranasal administration allows direct transport along the olfactory nerve to the CNS, bypassing the blood-brain barrier. The N-acetyl modification blocks N-terminal exopeptidase cleavage, extending half-life to an estimated 15–60 minutes versus 5–15 minutes for unmodified Semax.
Dosing protocols
| Purpose | Route | Dosage | Frequency | Notes |
|---|---|---|---|---|
| cognitive enhancement and neuroprotection research | nasal | 200–600 mcg | once or twice daily | Typical nasal spray dose is 200–600 mcg per session. Start at 200 mcg. Effects reported to last 6–12 hours. Cycle 4–8 weeks on, 2–4 weeks off. |
Dosing information is for educational purposes only. Consult a qualified healthcare professional before using any peptide.
Research summary
Semax has accumulated substantial preclinical evidence in Russian and Eastern European literature for neuroprotection in ischemic stroke, traumatic brain injury, and neurodegenerative conditions, with approved use in Russia and Ukraine. Rodent studies show rapid upregulation of BDNF transcription within 20 minutes of intranasal administration, with hippocampal BDNF protein levels elevated for up to 24 hours. N-Acetyl Semax specifically has been studied in gene expression analysis of neural tissue, demonstrating broader transcriptional network modulation than standard Semax. Human trials are limited to the base Semax compound; N-Acetyl Semax has no completed clinical trials as of 2026.
Side effects
Side effects vary by individual. This is not an exhaustive list. Report unusual symptoms to a healthcare professional.
Common stacks
Peptides commonly paired with N-Acetyl Semax for synergistic effects.
Legal status
Not FDA-approved in the US. Classified as a prescription medication in Russia and Ukraine for neurological conditions. Available from research peptide suppliers in the US and EU without prescription, primarily for research purposes.
Where to get it
Verified directory — coming soon
PeptaHub is building a verified supplier directory with third-party testing data, compliance status, and reader ratings.