Selank vs Semax
Written and maintained by the AVERON Research Desk · Last reviewed September 2026
Selank and Semax are often mentioned in the same breath. Both were developed at the same Russian institute, both are seven amino acids long, both are registered as medicines in Russia, and both are usually used as nasal sprays. But they come from different parent molecules and are associated with opposite effects: Selank with calm, Semax with focus.
Where they come from
Selank is based on tuftsin, a natural immune-modulating peptide. It is registered in Russia for anxiety.
Semax is based on a fragment of adrenocorticotropic hormone (ACTH), modified so that it has no hormonal activity. It is registered in Russia for stroke recovery and certain cognitive and nerve disorders.
Both were developed at the Institute of Molecular Genetics of the Russian Academy of Sciences, and both carry a short stabilising tail that helps them last longer in the body.
Side by side
| Selank | Semax | |
|---|---|---|
| Parent molecule | Tuftsin | ACTH fragment |
| Associated effect | Calm, reduced anxiety | Focus, mental drive |
| Registered use in Russia | Anxiety | Stroke, cognitive and nerve disorders |
| Proposed mechanism | GABA system and immune signalling | BDNF, a growth factor for nerve cells |
| Light-sensitive | No | Yes |
| Evidence level | Early human data | Early human data |
| Approved outside Russia | No | No |
| AVERON name | Selank | SMX-N |
The evidence for each
Selank: Russian clinical studies, including a 2008 trial comparing it with a conventional anti-anxiety medicine, reported similar effects on anxiety with less sedation.
Semax: animal studies have shown it increases BDNF in the brain, and Russian clinical studies have reported benefits in stroke recovery. Evidence for cognitive effects in healthy people is weak.
For both, the research has been conducted almost entirely in Russia and largely published in Russian-language journals, with little independent replication in controlled trials elsewhere.
Used together
The two are often combined, including in a single nasal spray, on the reasoning that Semax provides focus and Selank takes the edge off. No trial has tested the combination.
What neither does
Neither is a sedative, and neither is a stimulant. Their reported effects are subtle, and anyone expecting a dramatic change is usually disappointed. Neither is approved in the United States, the European Union or Indonesia.
A rule we apply to both
If you have a diagnosed mental health condition or take psychiatric medication, speak to your doctor before any use. We do not sell either without that conversation having taken place.
Frequently asked questions
Doses mentioned on this page are the arms of published trials, given to describe their results. They are not guidance.
Sources
- Zozulia AA, Neznamov GG, Siuniakov TS, et al.. Efficacy and possible mechanisms of action of a new peptide anxiolytic selank in the therapy of generalized anxiety disorders and neurasthenia. Zhurnal Nevrologii i Psikhiatrii imeni S.S. Korsakova, 2008;108(4):38–48. Link
- Dolotov OV, Karpenko EA, Inozemtseva LS, et al.. Semax, an analog of ACTH(4-10) with cognitive effects, regulates BDNF and trkB expression in the rat hippocampus. Brain Research, 2006;1117(1):54–60. Link