Semax
A synthetic heptapeptide analogue of ACTH(4-7) developed in Russia. Increases BDNF and NGF expression, enhances dopaminergic and serotonergic neurotransmission, and has demonstrated neuroprotective effects in stroke recovery. Fast-acting via nasal administration.
Reviewed & fact-checked by
Dr. Jane Smith, MD, PhDChief Medical Reviewer · Last updated: March 1, 2026
Medical Disclaimer: The information on this page is for educational and research purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment.
Mechanism of Action
Semax is a synthetic analogue of the ACTH(4-7) fragment -- the active sequence of adrenocorticotropic hormone responsible for cognitive effects without adrenal stimulation. Developed at the Institute of Molecular Genetics (Russian Academy of Sciences).
Key mechanisms:
- BDNF and NGF upregulation -- Semax is one of the most potent non-pharmaceutical stimulators of Brain-Derived Neurotrophic Factor. BDNF promotes neuroplasticity, neuronal survival, and new synaptic connections
- Dopaminergic enhancement -- increases dopamine receptor sensitivity in the prefrontal cortex, explaining the focus and motivation effects
- Serotonergic modulation -- normalises serotonin transmission, contributing to mood stabilisation
- Neuroprotection -- demonstrated protective effects against ischaemia-induced neuronal death in animal models and clinical stroke research
Why Intranasal?
The nasal route provides a direct anatomical pathway to the brain via the olfactory epithelium, bypassing the blood-brain barrier. Rapid onset -- effects typically felt within 20-30 minutes.
The Semax + Selank Protocol
The most popular combination in the Russian nootropic tradition. Semax drives cognitive performance; Selank manages the anxiety that often accompanies intense focused work. Together they create a balanced, sustainable cognitive state without the jitteriness of conventional stimulants.
Stacking Interactions
How Semax interacts with other compounds
Classic Russian peptide duo. Semax for focus and drive; Selank for calm. Ideal for high-pressure work sessions.
Alpha-GPC provides acetylcholine substrate; Semax upregulates BDNF and enhances neural transmission. Complementary mechanisms for acute cognitive performance.
Safety Profile — Tier B
Generally safe — moderate evidence
Contraindications
- ●Anxiety disorders - may exacerbate in some users
- ●Pregnancy - insufficient data
- ●Seizure disorders
Side Effects
- ●Increased anxiety or irritability (dose-dependent)
- ●Mild nasal irritation from intranasal administration
- ●Appetite suppression
- ●Headache in some users