Semax: What It Is and Its U.S. Regulatory Status

What is Semax?

Semax is a synthetic peptide made of seven amino acids. It is registered as a medicine in Russia, but it is not FDA-approved, and no approved medicine in the United States contains it.

Semax joins a short fragment of adrenocorticotropic hormone (ACTH), amino acids 4 to 7, to three extra amino acids (proline, glycine and proline) that make it more stable. It is often described as an analog of ACTH(4-10). It was developed in Russia with the participation of the Institute of Molecular Genetics of the Russian Academy of Sciences.

How it is thought to work

Proposed mechanisms come mainly from animal studies. Research in rats reported that Semax increased the activity of genes for brain growth factors, such as BDNF, and their receptors after an experimentally induced stroke. These findings do not show how Semax acts in people.

Human research

Most published human research on Semax comes from Russian groups and appears in Russian-language journals. Several studies looked at patients in the early period after an ischemic stroke, comparing people who received Semax on top of standard care with people who did not. One such study included 30 patients given Semax and a comparison group of 80.

Studies like these were small, and large placebo-controlled trials of the kind the FDA requires for approval have not been published.

U.S. regulatory status

Current status: Not FDA-approved.

Semax has not gone through the FDA review that a drug must pass before it can be marketed. Its compounding status has changed several times:

• Semax was placed in Category 2 of the FDA's interim 503A lists, the group of bulk substances that raise significant safety risks.
• April 2026: the FDA removed Semax and 11 other peptides from Category 2 after the nominations were withdrawn. Removal did not make Semax eligible for 503A compounding.
• July 24, 2026: the FDA's Pharmacy Compounding Advisory Committee reviewed Semax for cerebral ischemia, migraine and trigeminal neuralgia and voted to recommend adding it to the 503A bulks list, even though FDA staff had recommended against it. The vote is not binding.

As of late September 2026, the FDA had not added Semax to the 503A bulks list. Any change would require FDA agreement and a formal rulemaking process with public comment. Products labeled "for research purposes only" or "not for human consumption" are not approved medicines, and the FDA has not reviewed their contents, purity or quality.

Documented safety information

In its safety summary, the FDA said compounded Semax may pose a risk of immunogenicity (an unwanted immune response) for certain routes of administration, because of possible aggregation and peptide-related impurities. It added that it has no, or limited, safety information for the proposed routes, so it lacks enough information to know whether the drug would cause harm in humans.

FDA briefing materials for the July 2026 meeting described the available studies of the peptides under review as short, small and insufficient to establish safety or effectiveness.

Sport

Semax is not named on the World Anti-Doping Agency (WADA) 2026 Prohibited List. Athletes should confirm the status of any substance with their anti-doping organization.

Why Peptide Labs does not sell Semax

Peptide Labs does not sell this compound. This page is general information, not medical advice. We are not a pharmacy, we do not supply Semax, and we do not point readers to anyone who does.

For personal medical questions, including questions about stroke recovery or migraine, the right person to ask is a licensed healthcare provider.

Related reading

See the full list of compound profiles in the Peptide Guide. For the related Russian-developed peptide, see our profile of Selank. Other peptides reviewed by the advisory committee in 2026 include BPC-157 and epitalon. You can also read whether peptides are legal in the U.S.