Is Semax approved or legal?

Semax is reportedly a registered medicine in Russia for stroke and cognitive indications but is not approved by the FDA, EMA, or most other regulators. Internationally it is sold as a research chemical for research use only, not for human consumption. Legality of possession varies by jurisdiction.

What dose is used and what is the half-life?

There is no internationally validated dose. Russian stroke protocols used roughly 12-18 mg/day intranasally over several days; lower doses are used for cognitive indications. The intact peptide's plasma half-life is only minutes, but effects are reported to last many hours via the active metabolite Pro-Gly-Pro. This is reference information, not dosing advice.

Does Semax actually improve cognition?

There is credible Russian clinical evidence for stroke recovery and consistent preclinical neuroprotective data, but use as a general nootropic in healthy people rests mainly on mechanism and anecdote rather than controlled trials. The neuroprotective signal is stronger than the healthy-user cognitive-enhancement evidence.

It is most commonly given intranasally as a reconstituted solution, which also allows possible direct nose-to-brain transport; subcutaneous use is also discussed. Oral bioavailability is effectively negligible. No route has rigorously validated human dosing outside the Russian system.

It is described as well tolerated in available studies and is said to lack the hormonal activity of full ACTH, but long-term and independent safety data are limited. Possible issues include nasal irritation and overstimulation, and unregulated product quality is a real risk. It is not approved for human use and should be treated as a research compound.

Cognitive

Semax

Also known as: Met-Glu-His-Phe-Pro-Gly-Pro, ACTH(4-10) analog, N-acetyl Semax (acetylated form)

A synthetic ACTH(4-10)-derived heptapeptide studied as a neuroprotective nootropic, used in Russia for stroke and cognitive indications but unapproved elsewhere. Research use only.

Last updated July 11, 2026

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Overview

Semax is a synthetic heptapeptide (Met-Glu-His-Phe-Pro-Gly-Pro) derived from the 4-10 fragment of adrenocorticotropic hormone (ACTH), with a Pro-Gly-Pro C-terminal extension added to slow enzymatic degradation. Unlike full ACTH, Semax is described as lacking hormonal (corticotropic) activity while retaining effects on the central nervous system, and it is studied as a neuroprotective and nootropic agent, typically given as an intranasal solution. Semax is unusual among research peptides in that it has been used clinically in humans, but almost exclusively within the Russian medical system, where it is reportedly registered for indications including acute ischemic stroke, transient ischemic attack, cognitive disorders, and certain optic-nerve conditions. Russian clinical reports describe improved neurological recovery and raised BDNF levels in stroke patients, and preclinical work consistently shows neuroprotective and neurotrophic effects. However, much of this evidence consists of relatively small studies, often without large independent double-blind placebo-controlled replication outside Russia. Semax is not approved by the FDA, EMA, or most regulators outside Russia, and internationally it is sold as a research chemical labeled "for research use only." This entry summarizes the available science and community-reported practice for reference only; it is not medical advice and does not endorse human use.

How it works

Semax's central effects are attributed primarily to modulation of neurotrophic factors and neurotransmitter systems. The most consistently reported action is rapid upregulation of brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF) and their receptors, which is thought to support neuronal survival, synaptic plasticity, and recovery after ischemic injury. Semax is also reported to influence the dopaminergic, serotonergic, and cholinergic systems, to have antioxidant and anti-inflammatory/neuroprotective effects in ischemia models, and to modulate the activity of regulatory peptidases. A notable feature is that Semax is metabolized to the dipeptide/tripeptide fragment Pro-Gly-Pro (PGP), which is itself biologically active and is thought to contribute to longer-lasting effects despite the parent peptide's very short plasma life. These mechanisms are well supported in animal and cell models; their precise contribution to clinical outcomes in humans is less firmly established.

Researched effects

Clinical Improves neurological recovery and raises plasma BDNF when used in acute/recovery-phase ischemic stroke in Russian clinical studies
Preclinical Provides neuroprotection and reduces infarct/ischemic damage in animal stroke models
Preclinical Upregulates BDNF and NGF expression and supports synaptic plasticity
Preclinical Antioxidant and anti-inflammatory effects in models of cerebral ischemia
Anecdotal Reported improvements in focus, mental energy, motivation, and mood by community users
Anecdotal Anecdotally used as a general cognitive enhancer and for recovery from mental fatigue

Evidence levels: Clinical (human trials) · Preclinical (animal/lab) · Anecdotal (community-reported).

Dosing reference

For research reference only — not a recommendation.

Clinical / studied dosing

No FDA/EMA-approved dosing exists. In Russian clinical practice, intranasal Semax (commonly a 0.1% or 1% solution) has been used for stroke at roughly 12-18 mg per day across multiple administrations for several days, and at lower doses for cognitive/asthenic indications. These figures come from the Russian system and small studies and should not be treated as validated international clinical guidance.

Community-reported dosing (anecdotal)

Anecdotal and research-reference only; not medical advice. Community sources and vendor guides commonly describe intranasal Semax at roughly 300 mcg to a few milligrams per day (often a small number of drops of a reconstituted solution once or twice daily), used in short cycles for cognitive or mood goals. N-acetyl Semax and N-acetyl Semax amidate variants are marketed as longer-acting. These figures are unverified community practice, vary widely between sources, and are not tested safe or effective doses.

Half-life: The intact parent peptide has a very short plasma half-life (reported on the order of only a few minutes after administration). However, Semax is broken down to the active fragment Pro-Gly-Pro, and functional/therapeutic effects are reported to persist for many hours (sources commonly cite up to roughly 20-24 hours from a single dose). Detailed human pharmacokinetics are not fully characterized in the international literature.
Routes: intranasal, subcutaneous

Safety & side effects

Semax is generally described as well tolerated in the available Russian studies, with few reported adverse events at the doses used and no major hormonal effects attributed to it (it is described as lacking the corticotropic activity of full ACTH). However, long-term and large-scale safety data outside Russia are limited, and independent international verification is sparse. Reported or plausible issues include nasal/local irritation with intranasal use and, anecdotally, overstimulation, irritability, or sleep disturbance in some individuals. Product quality is a real-world risk: research-grade material is unregulated and may vary in purity, identity, or sterility. Semax is not FDA/EMA-approved and is sold for research use only, not for human consumption. This information is for research reference only and is not a recommendation for human use.

Research summary

Semax has a comparatively substantial human track record for a research peptide, but one concentrated almost entirely within Russia. Russian clinical reports, including studies by Gusev and colleagues, describe Semax improving functional recovery and raising plasma BDNF in patients at different stages of ischemic stroke, and it is reportedly a registered medicine there for stroke and cognitive indications. Preclinical research is broad and consistent: animal and cell studies show neuroprotection in ischemia, upregulation of BDNF and NGF and their receptor genes, and antioxidant/anti-inflammatory effects, with the active metabolite Pro-Gly-Pro thought to extend the duration of action beyond the parent peptide's brief plasma half-life. The principal limitation is the strength and independence of the human evidence. Many clinical studies are relatively small, and there is limited large-scale, independent, double-blind placebo-controlled replication outside the Russian system, which makes the effect sizes and generalizability harder to judge by international standards. The popular use of Semax as a general nootropic in healthy people is supported mainly by mechanism and anecdote rather than by controlled cognitive-enhancement trials. On balance, Semax is a mechanistically well-characterized neuroprotective peptide with real but geographically narrow clinical evidence for stroke/cognitive indications, and unproven, largely anecdotal status as a healthy-user nootropic. It is appropriate to frame it as an experimental research compound, not a validated medicine, and to read its claims with the regulatory and evidentiary context in mind.

FAQ

Is Semax approved or legal?: Semax is reportedly a registered medicine in Russia for stroke and cognitive indications but is not approved by the FDA, EMA, or most other regulators. Internationally it is sold as a research chemical for research use only, not for human consumption. Legality of possession varies by jurisdiction.
What dose is used and what is the half-life?: There is no internationally validated dose. Russian stroke protocols used roughly 12-18 mg/day intranasally over several days; lower doses are used for cognitive indications. The intact peptide's plasma half-life is only minutes, but effects are reported to last many hours via the active metabolite Pro-Gly-Pro. This is reference information, not dosing advice.
Does Semax actually improve cognition?: There is credible Russian clinical evidence for stroke recovery and consistent preclinical neuroprotective data, but use as a general nootropic in healthy people rests mainly on mechanism and anecdote rather than controlled trials. The neuroprotective signal is stronger than the healthy-user cognitive-enhancement evidence.
How is Semax taken?: It is most commonly given intranasally as a reconstituted solution, which also allows possible direct nose-to-brain transport; subcutaneous use is also discussed. Oral bioavailability is effectively negligible. No route has rigorously validated human dosing outside the Russian system.
Is Semax safe?: It is described as well tolerated in available studies and is said to lack the hormonal activity of full ACTH, but long-term and independent safety data are limited. Possible issues include nasal irritation and overstimulation, and unregulated product quality is a real risk. It is not approved for human use and should be treated as a research compound.

References

All content is for research and educational use only and is not medical advice. Products are sold for laboratory research only and are not for human consumption.

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