Peptides/Sleep, mood and focus
Semax
Also sold as N-acetyl semax, ACTH 4-10 analogue
A nootropic nasal spray from the same Russian programme as Selank. Used there after stroke; sold everywhere else for focus and memory.

At a glance
What people use it for
- Focus and mental clarity
- Memory and learning
- Marketed for recovery after brain injury
How it is taken
Sold as a nasal spray, sometimes as a powder for injection.
Evidence
No human trials
Good to know
- Human evidence is almost entirely Russian and not independently replicated
- Unapproved and unregulated outside Russia
- Nasal irritation is common
- Effects on brain chemistry over years are unknown
Semax is a short fragment of ACTH with the hormonal activity removed, leaving effects on the brain. It shares a research lineage with Selank and the same regulatory situation: a registered medicine in Russia, unapproved anywhere else.
What people take it for
Concentration, mental stamina and memory, particularly among students and people doing demanding cognitive work. It is one of the better known nootropics sold as a peptide.
In Russia it is used clinically after ischaemic stroke and for cognitive disorders, which is a considerably more serious application than the focus-spray marketing suggests.
What the evidence shows
Russian trials report benefits after stroke and effects on BDNF, a protein involved in the growth and maintenance of neurons. Animal work supports neuroprotective activity.
The same caveat as Selank applies, and it is the important one. The evidence base sits almost entirely within one country's literature and has not been replicated by independent groups elsewhere. Nothing about that makes it false. It does mean nobody outside that system has checked.
For healthy adults wanting sharper focus, there is no good trial at all.
What to know before
Mechanisms and outcomes are different things. Raising BDNF in an animal is a promising start; thinking more clearly in a meeting is the result people want, and that step has not been shown yet.
Last reviewed .