Semax
Also known as: ACTH(4-10) analogue
An approved medicine in Russia with a real clinical literature — almost none of which has been replicated anywhere else, which is the whole story.
Regulatory status: Registered as a medicine in Russia for stroke, cognitive disorders and certain optic-nerve conditions; not approved in the UK, EU or US.
What it is
Semax is a synthetic peptide based on a fragment of adrenocorticotropic hormone, modified so it lasts longer in the body without the hormonal activity of the parent molecule. It is a registered medicine in Russia, prescribed for stroke recovery and cognitive complaints, and sold elsewhere as a research chemical.
Composition
A modified ACTH(4-10) fragment with an added proline-glycine-proline tail for stability. Usually presented as a nasal spray.
Proposed mechanism
Proposed mechanisms include increasing brain-derived neurotrophic factor and modulating the dopamine and serotonin systems. These come largely from animal work rather than from human mechanistic studies.
Claimed benefits
Improved focus and memory, protection of brain tissue after stroke, and reduced mental fatigue.
What the evidence shows
Silver· human data. This is the unusual case where the honest answer is that it may work and nobody outside Russia has checked. There is a genuine clinical literature behind its Russian registration, including trials in ischaemic stroke. That literature is largely published in Russian, rarely replicated by independent groups, and not held to the reporting standards Western regulators require.
Neither dismissing it nor accepting it is defensible on the evidence. What can be said is that a body of trial evidence confined to one country's literature for three decades is a pattern that should lower confidence rather than raise it.
Legal & regulatory status
Registered as a medicine in Russia. Not approved in the UK, EU or US, where it is sold as an unregulated research chemical. Anyone competing should check current WADA status directly.
Known risks & unknowns
Its Russian clinical use suggests reasonable short-term tolerability, and it is not a stimulant. What is missing is independent long-term safety data — and what is sold online is not the registered medicine but an unregulated product of unverifiable purity.
Sources
Frequently asked questions
- What is Semax?
- A synthetic peptide based on a fragment of adrenocorticotropic hormone, modified so it lasts longer in the body without the hormonal activity. It is a registered medicine in Russia, where it is prescribed for stroke recovery and cognitive complaints, and it is sold elsewhere as a research chemical.
- Does Semax actually work?
- This is the unusual case where the honest answer is 'possibly, but nobody outside Russia has checked'. There is a real clinical literature behind its Russian registration, including trials in ischaemic stroke. That literature is largely published in Russian, rarely replicated by independent groups, and not held to the reporting standards that Western regulators require — so the claims are neither dismissible nor established.
- What does it do to the brain?
- The proposed mechanisms include increasing brain-derived neurotrophic factor and modulating the dopamine and serotonin systems, which is consistent with reported effects on attention and mood. These mechanisms come mostly from animal work.
- Is Semax safe?
- Its Russian clinical use suggests reasonable short-term tolerability, and it is not a stimulant. What is missing is independent long-term safety data, and what is sold online is an unregulated research chemical of unverifiable purity rather than the registered medicine.
Related compounds
- Selank (Silver)
An evidence-tiered explainer on Selank: a Russian anxiolytic peptide with a small domestic evidence base and no independent replication.
- DSIP (Unproven)
An evidence-tiered explainer on DSIP (delta sleep-inducing peptide): named for an effect that fifty years of research has not reliably reproduced.
- Epithalon (Unproven)
An evidence-tiered explainer on epithalon: a synthetic peptide marketed for longevity and telomere lengthening, whose human evidence is limited, dated and far from establishing any anti-ageing effect.
Written and reviewed by Mathew Beale, MSc Biotechnology, University of Reading.
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