Semax
Semax is a nasal peptide developed in Russia, where it is an approved medicine for stroke care. In the US it is not FDA-approved, and it is used mostly for focus and cognition, a use with much thinner evidence.
- Legal lane: compounded on prescription under the October 2026 interim policy. Not FDA-approved.
- Evidence grade: C
- Form covered by the policy: Semax free base, intranasal only
- Established human dose: none in the US. Russian clinical practice is described below.
What it is
Semax is a synthetic seven-amino-acid peptide modeled on a fragment of the hormone ACTH. It is given as nasal drops or spray.
What the evidence shows
The strongest human evidence is in stroke recovery, from Russian clinical trials published in 1997 and 2018, where Semax was added to standard hospital care. Those trials are small to mid-sized and have had little replication outside Russia. No large multi-center trials have been run in Western populations.
For focus and memory in healthy people, the evidence is limited to small or older studies. Much of the foundational research is in Russian-language journals and is hard to evaluate independently.
The July 2026 FDA advisory committee considered Semax for cerebral ischemia, migraine and trigeminal neuralgia, and recommended it.
Legal status
Semax left the FDA's restricted category in April 2026 and is covered by the HHS interim policy published October 30, 2026. The policy covers the nasal form only. Semax is prohibited in sport as a non-approved substance.
Reported dosing
There is no FDA-approved Semax product and no official US dosing. What follows describes Russian clinical practice and published studies, as summarized in the sources below.
| Setting | Strength | Reported use |
|---|---|---|
| Cognition studies | 0.1% nasal solution | Roughly 400 to 600 micrograms a day, split into one to three doses, often for one to four weeks |
| Stroke care, in hospital | 1% nasal solution | Roughly 6,000 micrograms a day in courses of five to ten days, under clinician direction |
Note the tenfold difference in strength between the two solutions. Variants such as N-acetyl Semax are dosed differently and are not interchangeable.
Safety
- Semax is generally reported as well tolerated, with nasal irritation the most common complaint.
- Long-term safety data and studies of interactions with psychiatric medications are lacking.