Semax
Also known as ACTH (4-10) analog
A synthetic ACTH-derived peptide used in Russia as a nootropic and neuroprotective, with little Western trial data.
Medically reviewed by Dr. Jonathan Snipes, MD
Reviewed for clinical accuracy · Last reviewed July 22, 2026 · Review policy
Quick answer
Semax is a synthetic peptide derived from ACTH, used in Russia as a nootropic and neuroprotective agent but with little independent Western trial validation. It is not FDA-approved in the US, and its compounding pathway was under FDA review at the July 2026 PCAC meeting, which flagged anticoagulant and stimulant-potentiation signals.
- Type
- Synthetic ACTH (4-10) analog
- FDA status
- Not approved; compounding under review
- Human evidence
- Russian clinical use; limited Western data
- Evidence grade
- D (Preclinical Only)
- Banned in sport
- Not specifically listed
Key takeaways
- →Semax is a modified fragment of the hormone ACTH, developed and used clinically in Russia for cognitive and neurological indications.
- →Independent, Western-standard randomized trials are limited, so the broader evidence base is weaker than its clinical use elsewhere suggests.
- →It is not FDA-approved in the US.
- →The FDA's July 2026 PCAC review flagged anticoagulant activity and potentiation of stimulant effects as safety concerns.
Semax is a synthetic peptide based on a fragment of adrenocorticotropic hormone (ACTH). It has a real clinical history in Russia, where it has been used for cognitive, neurological and stroke-related indications, which sets it apart from purely experimental compounds. The gap is validation: independent trials meeting Western regulatory standards are limited, so US regulators treat it as unproven.
How Semax works
Semax is thought to influence brain-derived neurotrophic factor (BDNF) and other neuromodulatory pathways, which is the proposed basis for its nootropic and neuroprotective claims. Much of the supporting research comes from Russian laboratories, and the mechanisms have not been confirmed in large independent human trials.
What the evidence shows, by use
Each use is graded on the same A-E scale, based on human-trial quality rather than popularity.
Cognitive enhancement / nootropic
DPreclinical OnlyUsed clinically in Russia for cognition, but independent Western randomized trials are limited, so the evidence is not established by US standards.
Neuroprotection / stroke recovery
DPreclinical OnlyStudied in Russian clinical settings; broader confirmatory trial evidence is lacking.
Dosing
There is no FDA-approved Semax product in the US and no US-validated dose. It is often used as a nasal spray in the settings where it is marketed. Because US supply is largely unregulated research-grade material, any use should be through a licensed clinician rather than research-chemical vendors.
Side effects
- •Injection or nasal-site irritation · Reported
- •Headache · Reported
- •Anticoagulant / bleeding-related signals · Reported
- •Potentiation of stimulant effects · Reported
Legal & regulatory status
Semax is not FDA-approved in the US. Its compounding pathway was under FDA review at the July 2026 PCAC meeting, which flagged anticoagulant and stimulant-potentiation signals.
Is Semaxlegal? Full regulatory status →Where to get it: TeleRanked independently ranks the telehealth providers that offer clinician-prescribed peptides. See our Peptide Therapy rankings. We rank providers, we do not sell compounds, and rankings are never for sale.
Frequently asked questions
Does Semax work as a nootropic?+
It is used clinically in Russia for cognitive indications, but independent Western trials are limited, so by US evidence standards its cognitive benefit is not established.
Is Semax safe?+
Independent safety data is limited. The FDA's July 2026 review flagged anticoagulant activity and potentiation of stimulant effects, which are particularly relevant for people on blood thinners or stimulants.
How we grade evidence
Grade D: Preclinical Only. Evidence is largely limited to animal or laboratory studies; human data is minimal or absent. Our A-E scale reflects the strength of human evidence, not how popular a compound is.
Sources
- 1.July 23-24, 2026: Meeting of the Pharmacy Compounding Advisory Committee · U.S. Food & Drug Administration
- 2.Compounding and the FDA: Questions and Answers · U.S. Food & Drug Administration