Semax: how it got to PCAC

Background

Semax is a synthetic seven-residue peptide of the sequence Met-Glu-His-Phe-Pro-Gly-Pro — an analogue of fragment 4-10 of adrenocorticotropic hormone (ACTH) in which the C-terminal tetrapeptide of the parent sequence has been replaced with Pro-Gly-Pro to extend in-vivo half-life. The compound is recorded in PubChem under CID 9810797 (PubChem CID 9810797).

The peptide was developed in the 1980s at the Institute of Molecular Genetics of the Russian Academy of Sciences in Moscow. The 2018 review by Koroleva and Myasoedov in Biology Bulletin described the development history and registration status (PMID:30607450):

Semax is a synthetic peptide preparation, an analogue of fragment ACTH(4-10), that was developed at the Institute of Molecular Genetics of the Russian Academy of Sciences and is registered in the Russian Federation.

Semax holds a national marketing authorization in the Russian Federation for indications that include ischemic stroke and certain optic-nerve and cognitive conditions. It has no marketing authorization in the United States, the European Union, the United Kingdom, Canada, or Australia, and is not the subject of an FDA New Drug Application as of the date of this writing.

What’s on the agenda

Semax is one of three peptides on the agenda of the FDA Pharmacy Compounding Advisory Committee meeting scheduled for July 24, 2026. The committee will provide non-binding scientific and medical advice to the agency on whether the substance should be added to the 503A bulks list (FDA PCAC). PCAC’s recommendation does not bind the FDA; the agency’s listing decision follows the meeting and may be issued months or years later.

The agency’s evaluation framework, summarized on its 503A reference page (FDA bulks page), weighs four factors: physicochemical characterization, safety, evidence of effectiveness or lack of effectiveness, and historical use of the substance in compounded products.

A peptide that has been registered in another jurisdiction does not, by itself, satisfy the 503A criteria. The 503A pathway requires that the substance be the subject of a USP or NF monograph, be a component of an FDA-approved drug, or appear on the FDA’s bulks list. Semax is the subject of none of those at the time of this writing — which is why the substance was nominated and referred to PCAC in the first place.

Why it matters

The peer-reviewed clinical literature on Semax is concentrated in Russian-language journals, principally the Korsakov Journal of Neurology and Psychiatry (S. S. Korsakov Journal of Neurology and Psychiatry). Published clinical reports have included observational and small randomized studies in ischemic stroke patients, summarized in papers such as Gusev and colleagues (PMID:26620191). Reviewers writing in English-language journals have noted that the bulk of Semax clinical evidence originates from a small number of investigator groups and that independent replication outside the Russian Federation is limited.

The FDA’s evaluation will, per the agency’s own framework, address the strength and independence of that evidence base, the safety record from compounding-pharmacy use in the United States (which the FDA documents through its inspections, MedWatch reports, and warning-letter archive), and the physicochemical characterization of the bulk substance available to U.S. compounders. The briefing document the agency posts ahead of the meeting will summarize the agency’s reading of those four factors.

This page reports the sequence, the development history, and the cited record of how Semax came to be on the July 24 PCAC agenda. It does not predict the committee’s recommendation or the FDA’s final listing decision; pepi.ninja will summarize the briefing materials on the Semax peptide page when they are released.