Semax
A synthetic peptide derived from a fragment of ACTH (4-10) developed in Russia as a nootropic and neuroprotective agent. It is used clinically in Russia for stroke, cognitive disorders and attention, but the supporting trials are largely Russian and not widely replicated internationally. Typically taken intranasally; claimed to improve focus, memory and recovery from neurological insults.
01 Overview
Semax is a heptapeptide analogue of the ACTH(4-10) fragment, modified for stability, developed at the Institute of Molecular Genetics in Moscow. In Russia it is an approved medicine used for ischaemic stroke, transient ischaemic attack, cognitive and attention disorders, and even optic nerve conditions, usually as a nasal solution. It is claimed to enhance memory, attention and mental stamina and to protect neurons, with mechanisms attributed to increased BDNF/NGF expression and modulation of the melanocortin and dopaminergic systems.
The honest picture mirrors Selank: real clinical use exists in one country, but the evidence base is dominated by Russian studies of variable size and quality with limited independent Western replication. It is not approved in the US or EU and is sold as a research chemical. Tolerability is generally reported as good, though rigorous long-term safety data are lacking.
02 Mechanism
An ACTH(4-10) analogue lacking corticotropic activity that is proposed to upregulate BDNF and NGF, modulate the melanocortin, dopaminergic and serotonergic systems, and exert neuroprotective and neurotrophic effects.
03 Dosing
| Tier | Dose | Route | Notes |
|---|---|---|---|
| Anecdotal / Russian use | 300–900 mcg/day | Insufflated | Intranasal dosing (0.1% solution common; higher-strength used for neurological indications). Convention-based outside Russia. |
04 Effects
| Effect | Magnitude | Evidence | |
|---|---|---|---|
| Improved focus and cognitionReported improvements in attention, memory and mental stamina in Russian clinical use; limited independent replication. | Small Russian trials | Clinical | |
| Neuroprotection in strokeUsed in Russia as an adjunct in ischaemic stroke; supporting trials are largely Russian. | Clinical | ||
| Increased BDNF/NGF expressionNeurotrophic effects demonstrated mainly in animal and in-vitro studies. | Preclinical |
05 Side effects
| Effect | Severity | Frequency | Evidence | Countermeasures |
|---|---|---|---|---|
| Nasal irritation (intranasal)Local nasal irritation or discomfort with intranasal dosing. | Mild | Common with nasal use | Anecdotal | |
| Overstimulation / irritabilitySome users report irritability, restlessness or headache, particularly at higher doses. | Mild | Occasional | Anecdotal | |
| Unknown long-term safetyLong-term and Western safety data are lacking outside Russian studies. | Mild | Unquantified | Unconfirmed |