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Semax

Semax is a short peptide registered as a prescription nasal drug in Russia but not approved in the US. See the small Russian trials, lab findings, FDA's 2026 review and the gaps.

Content last updated . This page has not been medically reviewed.

Quick answer
Semax is a synthetic seven-amino-acid peptide developed in Russia and related to a fragment of the hormone ACTH. It is a registered prescription nasal-drop medicine in Russia, but it is not approved in the United States, and FDA reviewers in 2026 concluded there was insufficient evidence of effectiveness for the uses they evaluated. [1] The human studies we found are small and mostly published in Russian journals. Everyday claims of better focus or memory in healthy people have no good support.

Identity and naming

The Russian state drug register lists Semax with the chemical name Methionyl-glutamyl-histidyl-phenylalanyl-prolyl-glycyl-proline, a heptapeptide (Met-Glu-His-Phe-Pro-Gly-Pro). [2] The literature describes it as an analogue of the ACTH(4-10) fragment that lacks hormonal activity. [3] FDA's reviewers note that semax free base and semax acetate are different active ingredients, and they cite inconsistent naming that does not follow standard chemical nomenclature. [1] Brand names, nasal sprays and injections sold online may not match the product studied. See research peptide naming and identity problems.

What the research shows

  • Stroke recovery. A Russian report of 110 patients after ischemic stroke, grouped by rehabilitation timing and by Semax use, found higher blood BDNF (a brain growth protein) and better functional scores with Semax. [4] BDNF is a biomarker, and the abstract describes no placebo group. An older study compared 30 patients given Semax with 80 given standard care and reported faster recovery of some neurological functions. [5] Label: promising but limited.
  • Optic nerve disease. A controlled trial added Semax to standard treatment and reported better visual function. [6] Label: promising but limited.
  • Motor neuron disease. In a 27-patient open-label study, Semax did not change the disease course or clinical scores; quality-of-life scores improved. [7] Label: no good evidence of benefit on disease progression.
  • Animals and cells. In mice bred to model Alzheimer's disease, Semax and a derivative improved test performance and reduced amyloid deposits. [8] Label: preclinical (cells/animals only). FDA's reviewers also noted that in mice Semax increased amphetamine-induced dopamine release, which they called concerning, and that no abuse-potential studies were found. [1]
  • Healthy people, attention, ADHD, mood. Proper evidence not found: we read no controlled human trial in healthy people, and FDA's reviewers noted that a review cited a few older studies of nootropic effects in healthy adults, which they did not weigh. [1] The one ADHD item we found is a hypothesis paper, not a trial. [3] ClinicalTrials.gov returned no registered Semax study. [9]

Related reading

Selank is a different peptide often grouped with it. For wider context see neurological and cognitive peptide research and nootropics.

Frequently asked questions

Is Semax approved?

In Russia it is registered as a prescription nasal drug. In the US it is not approved. [2][1]

Does Semax improve memory in healthy adults?

Proper evidence not found. Human studies we found were in patients, and FDA found insufficient evidence for the uses it reviewed. [1]

Is Semax the same as Selank?

No. Semax is an analogue of an ACTH fragment [3], while Selank is an analogue of tuftsin [15].

What did FDA say in 2026?

Its reviewers proposed not adding Semax to the compounding list. They cited poor characterization, thin safety data and insufficient evidence. [1]

More details: evidence, limits and cautions

The details behind this page: cautions, limits of the evidence and where sources disagree. Open any note to read it.

How to read the evidence labels

Labels used on this page: approved medicine (Russia only, as read), promising but limited, preclinical (cells/animals only), insufficient evidence, marketing claim and Proper evidence not found. A biomarker such as a blood protein level is not a health outcome.

Regulatory status
PlaceWhat we read
RussiaTwo Semax nasal-drop registrations (0.1% and 1%) by one Russian manufacturer appear as valid in the state register, both marked prescription-only. Classified in the nootropic group (ATC N06BX). [2][10] Approved medicine there.
United StatesNot a component of any FDA-approved drug. In May 2026 FDA reviewers proposed not adding it to the 503A bulks list for cerebral ischemia, migraine and trigeminal neuralgia. [1] The advisory committee was scheduled to discuss it July 24, 2026. [11] I could not read an official vote or final decision, so none is stated.
Earlier FDA listListed among withdrawn nominations, with an immunogenicity concern and limited safety information. [12]
OthersNot verified.

FDA's reviewers did not weigh the Russian-language trials because translations were not provided. [1] Compounded drugs are not FDA-approved. [13] Laws change and this is not legal advice.

Safety and quality
FDA found no human pharmacokinetic studies and no safety data for injection; the only route in the literature was nasal. One older abstract raised a question about blood clotting effects, so FDA noted a possible bleeding concern. [1] The agency's database held one consumer report of eye pain and burning after nasal drops bought online. [1] FDA also warns that unapproved products may be contaminated or contain different ingredients. [14] See peptide safety and adverse events. Anyone taking blood thinners or planning surgery should speak to a clinician before any such product.
References
  1. U.S. Food and Drug Administration. FDA Briefing Document for Semax-Related Bulk Drug Substances, Pharmacy Compounding Advisory Committee, July 23-24, 2026. Read 2026-10-22.
  2. Ministry of Health of the Russian Federation. State Register of Medicines (GRLS): Semax nasal drops, registration detail page (found by searching the register for the trade name, valid registrations only). Read 2026-10-22.
  3. Semax, an analogue of adrenocorticotropin (4-10), is a potential agent for the treatment of attention-deficit hyperactivity disorder and Rett syndrome. Med Hypotheses 2007. Read 2026-10-22.
  4. The efficacy of semax in the treatment of patients at different stages of ischemic stroke. Zh Nevrol Psikhiatr Im S S Korsakova 2018. Read 2026-10-22.
  5. Effectiveness of semax in acute period of hemispheric ischemic stroke (a clinical and electrophysiological study). Zh Nevrol Psikhiatr Im S S Korsakova 1997. Read 2026-10-22.
  6. Evaluation of therapeutic effect of new Russian drug semax in optic nerve disease. Vestn Oftalmol 2000. Read 2026-10-22.
  7. The study of chronic partial denervation and quality of life in patients with motor neuron disease treated with semax. Zh Nevrol Psikhiatr Im S S Korsakova 2007. Read 2026-10-22.
  8. The Potential of the Peptide Drug Semax and Its Derivative for Correcting Pathological Impairments in the Animal Model of Alzheimer's Disease. Acta Naturae 2025. Read 2026-10-22.
  9. U.S. National Library of Medicine. ClinicalTrials.gov search, intervention "semax" (0 records). Read 2026-10-22.
  10. Ministry of Health of the Russian Federation. State Register of Medicines (GRLS): second Semax nasal drops registration, detail page. Read 2026-10-22.
  11. U.S. Food and Drug Administration. July 23-24, 2026: Meeting of the Pharmacy Compounding Advisory Committee (meeting page and agenda; no vote record or final decision was read). Read 2026-10-22.
  12. U.S. Food and Drug Administration. Certain Bulk Drug Substances for Use in Compounding that May Present Significant Safety Risks (content current as of 04/22/2026). Read 2026-10-22.
  13. U.S. Food and Drug Administration. Compounding and the FDA: Questions and Answers. Read 2026-10-22.
  14. U.S. Food and Drug Administration. FDA warning letter to an online seller of unapproved drugs, reference 696885, February 26, 2025. Read 2026-10-22.
  15. Selank, a Peptide Analog of Tuftsin, Attenuates Aversive Signs of Morphine Withdrawal in Rats. Bull Exp Biol Med 2022. Read 2026-10-22.
Education, not medical advice. This page is for general information. It does not diagnose or treat any condition and is not a substitute for care from a qualified health professional. Natural does not automatically mean safe. Ask a clinician or pharmacist before changing your care, especially if you take medication, are pregnant or breastfeeding, or have a health condition.