What is Semax?
Semax is a lab-made peptide of seven amino acids, developed in Russia in the 1980s. It is built from a piece of ACTH, a stress hormone, but it doesn’t act as a hormone.
In Russia it has been a prescription medicine since the 1990s, given as a nasal spray. Elsewhere it is sold online as a “nootropic,” a brain-boosting supplement.
What does Semax do?
In animal and lab studies, Semax raises BDNF, a protein that helps brain cells survive and form connections, and affects dopamine and serotonin signaling. Researchers think this explains its protective effects on the brain after stroke.
What does the research on Semax show?
Most human research comes from Russia, where trials in stroke patients reported better recovery. Those studies were mostly small, often not blinded, and many aren’t available in full in English.
There are no good Western trials showing Semax improves focus, memory or mood in healthy people.
Semax side effects and risks
Side effects reported in Russian use are mild, mainly nasal irritation. But its effects in healthy people using it long-term are unknown, and the FDA has flagged possible immune reactions to compounded Semax.
Products sold online as research chemicals aren’t checked for purity or strength.
Is Semax legal?
Semax is approved only in Russia and some nearby countries, not by the FDA or the European Medicines Agency. In the US it is on the FDA’s list of compounding substances with safety concerns for outsourcing facilities.
In July 2026 an FDA advisory committee recommended allowing it in pharmacy compounding, but that is not an approval and the FDA still has to decide.