Semax

What it is

Semax is a synthetic peptide developed from an adrenocorticotropic hormone fragment. It is registered as a drug in Russia in intranasal forms, but it is not an FDA-approved drug component in the United States. Foreign registration does not establish U.S. approval or answer whether a differently formulated product has the same evidence.

What humans actually show

• Healthy-volunteer imaging: A 2018 study included 24 healthy volunteers—14 receiving intranasal Semax and 10 placebo—and measured resting-state functional connectivity. This was a small mechanistic imaging study, not a trial showing improved daily function or clinical benefit.
• Another small mechanistic study: A 2020 study of 52 healthy participants compared Semax, Selank, and placebo using resting-state connectivity. Again, the endpoint was brain-network measurement rather than a demonstrated treatment benefit.
• Clinical literature: Some studies from Russia report outcomes in neurologic settings, but FDA's review identifies design, reporting, route, substance-identity, and safety limitations. FDA concluded there is insufficient evidence for the nominated uses.

The existence of a human paper does not by itself establish that an online injectable product improves cognition, treats a condition, or is safe.

FDA and U.S. status

FDA evaluated Semax free base and Semax acetate for proposed uses including cerebral ischemia, migraine, and trigeminal neuralgia. Staff concluded the criteria weigh against 503A Bulks List inclusion. The briefing says neither substance is a component of an FDA-approved drug and raises characterization and safety concerns.

FDA also notes a route mismatch: the clinical literature it reviewed discussed intranasal use, while the nomination proposed subcutaneous injection. Evidence from one route cannot simply be assumed to characterize another.

On July 24, 2026, PCAC voted 8 yes, 5 no, 1 abstain on the free base and 8 yes, 5 no, 1 abstain on the acetate, recommending inclusion for both forms. The committee's recommendation is advisory: it does not approve Semax, establish clinical benefit, or itself place either form on the 503A Bulks List. FDA's final determination remains pending.

Risks and warning limits

FDA says the clinical information is insufficient to characterize Semax's safety profile. It also notes that most reviewed references did not discuss safety and flags a possible bleeding concern based on reported antithrombotic properties. This is a signal requiring study, not a quantified risk estimate.

PepCurrent does not provide dosing, sourcing, or product-selection advice.

What would change this answer

• FDA's written meeting record and final determination after the advisory recommendation
• Controlled trials with prespecified clinical outcomes
• Route-specific safety data and clear identification of free base versus acetate

Sources and records

• FDA staff briefing — Semax-related bulk drug substances (2026)
• Lebedeva et al., 2018 — small healthy-volunteer fMRI study
• Panikratova et al., 2020 — resting-state connectivity study
• FDA meeting page — July 23–24, 2026 PCAC
• FDA voting questions — exact free-base and acetate questions (PDF)
• FDA-linked Day 2 archived broadcast — Semax votes

Educational journalism only; not medical or legal advice. We do not link vendors or publish protocols.