What is Semax used for?

In Russia, Semax is approved for cognitive disorders, stroke treatment, attention deficit, and as an adjunct in optic nerve diseases. It is researched as a nootropic and neuroprotectant. Not approved in UK/EU.

Semax primarily works by increasing BDNF and other neurotrophic factors that support brain health and plasticity. It also affects multiple neurotransmitter systems and has anti-inflammatory properties.

Semax has been used safely in Russia for over 25 years with a generally good safety profile. However, comprehensive safety data from Western clinical trials is limited. Long-term effects require further study.

What is the difference between Semax and Selank?

Both are Russian nootropic peptides with different structures and primary effects. Semax is primarily a nootropic based on ACTH, while Selank is primarily anxiolytic based on tuftsin. They are sometimes used together.

Fact-checked by the Peptide Authority Editorial Board · Last reviewed: 1 February 2026

Share:X Post LinkedIn

Cognitive & Neurological•Updated 2026-02-01•5 min read

What Is Semax? Benefits, Research & Safety

A synthetic peptide based on ACTH, developed in Russia as a nootropic and neuroprotectant, approved there for cognitive disorders and stroke.

Share:X Post LinkedIn

Also known as:

MEHFPGP

Semax Acetate

CLimited human evidenceUK: Unlicensed (UK)WADA: Sport status unclear

UK summary: Not a licensed UK medicine. Russian-developed nootropic peptide derived from ACTH; used in Russia for some neurological indications. Most published evidence is from Russian groups with limited independent replication.

Quick Facts

Overview

Semax is a synthetic heptapeptide derived from the N-terminal fragment of adrenocorticotropic hormone (ACTH 4-7) with an added Pro-Gly-Pro sequence that enhances stability. Developed at the Institute of Molecular Genetics of the Russian Academy of Sciences, Semax is approved in Russia and several other countries for the treatment of cognitive disorders, stroke, and attention deficit. Unlike the parent ACTH molecule, Semax does not have hormonal (corticotropic) effects. Instead, it demonstrates primarily nootropic (cognition-enhancing) and neuroprotective properties. Research suggests it can enhance memory, learning, attention, and provide protection against various forms of neural damage. Semax is typically administered intranasally and has been used in Russia for over 25 years. It is prescribed for a range of conditions including cognitive impairment after stroke, attention deficit disorders, and as an adjunct in optic nerve diseases. The peptide is also reported to have immunomodulatory properties and has been studied for effects on gene expression related to neurotrophic factors and immune function. Semax is not approved for use in the UK, EU, or USA, where it remains a research compound.

Evidence standards summary

Semax — evidence and risk at a glance

Twenty standard modules scored against the Peptide Authority evidence grading methodology. Missing modules indicate the field has not yet been characterised editorially — treat absences as uncertainty rather than reassurance.

01Evidence snapshot

CLimited human evidenceOverall grade against our evidence grading methodology.

Not a licensed UK medicine. Russian-developed nootropic peptide derived from ACTH; used in Russia for some neurological indications. Most published evidence is from Russian groups with limited independent replication.

02Human evidence grade

DAnimal/cell evidence onlyStrength of evidence from published human trials.

03Preclinical evidence grade

CLimited human evidenceAnimal-model and in-vitro evidence quality.

04Regulatory status

UK: Not licensed. Research compound only.
EU: Not approved by EMA. Not available as a pharmaceutical.
Notes: Semax is approved in Russia and several other countries. It is not approved in Western countries. Products from non-pharmaceutical sources may have quality and authenticity concerns.

05Approved medical uses

None in the UK or EU as a finished medicine. (Or: not yet documented; treat as absence rather than approval.)

06Unapproved / promotional claims

Reverses cognitive decline in healthy adults.
Equivalent to modafinil with no side effects.
Speeds stroke recovery on par with NHS neurorehabilitation.
Safe for daily long-term cognitive enhancement.

07Common internet claims

Marketed as an ACTH-derived smart drug for exam prep and high-stakes work.
Sold as a stroke-recovery nootropic by grey-market nasal-spray retailers.
Recommended in biohacker stacks alongside Selank, methylene blue, and racetams.

08Claim vs evidence

Claim	Evidence	Human evidence?	Regulatory concern	Safer wording
“Improves cognitive function in healthy adults”	C	Limited	Moderate	Russian-language studies report cognitive effects in clinical populations; healthy-adult cognitive-enhancement claims are not well established.
“Neuroprotective after stroke”	C	Yes	Moderate	Approved for stroke recovery in Russia; not UK-licensed for this indication and not on NHS pathways.
“Safer than prescription nootropics”	E	No	High	Comparative safety claims need comparative trials.

09Safety uncertainty score

High

Limited human safety data; meaningful uncertainty about rare or long-term effects.

10Known adverse signals

Nasal irritation and sneezing.
Headache, fatigue, and altered mood reported anecdotally.
Unknown effects of chronic BDNF/melanocortin pathway activation.
Drug-drug interactions with antidepressants, stimulants, and steroids not characterised.

11Drug-interaction uncertainty

High

Interaction picture sparse; meaningful uncertainty when combined with other medicines.

12Anti-doping status

WADA: Sport status unclearWADA strict-liability framing applies.

13UK legal position

UK: Unlicensed (UK)

Not licensed. Research compound only.

Read the full UK legal guide → Research peptides and UK law

14EU legal position

Not approved by EMA. Not available as a pharmaceutical.

15What this page cannot tell you

Whether a UK-purchased nasal spray contains Semax at the labelled concentration.
How it interacts with SSRIs, methylphenidate, or atomoxetine in adult ADHD patients.
Whether long-term use changes endogenous melanocortin or BDNF tone.
What the WADA in-competition status is for athletes.

16Last reviewed

Last reviewed: 1 February 2026

Next review due: 1 February 2027

Spotted an error or something out of date? Send a correction.

17Citation quality score

DAnimal/cell evidence onlyQuality of the sources we cite, graded against the evidence grading methodology.

18Research gaps

Most positive human evidence comes from Russian-language journals without independent replication.
No Western Phase 3 cognitive-outcome trials.
Long-term safety unstudied in non-Russian populations.
Mechanism of nootropic action incompletely characterised.

19Safer alternatives / established care pathways

NHS post-stroke rehabilitation pathway (occupational therapy, neuro-physio, speech and language therapy).
GP review for adult ADHD assessment if attention is the underlying concern.
Structured sleep, exercise, and caffeine review before adding a compound.

20Doctor discussion prompts

Questions to ask a qualified clinician

These are starter questions you can adapt for a GP, specialist, pharmacist, or anti-doping advisor. The aim is to help you have a better-informed conversation — not to replace one.

Is Semax a licensed UK medicine?
If I'm researching neurological recovery, what UK-licensed pathways exist?
What is the quality of the Russian evidence base?

Discovery & History

Semax was developed in the 1980s and 1990s at the Institute of Molecular Genetics of the Russian Academy of Sciences. The development was led by Professor Nikolay Myasoedov, who also developed Selank. The peptide was designed based on ACTH 4-7, a fragment of adrenocorticotropic hormone that had been found to have cognitive effects independent of the hormone's primary function of stimulating cortisol release. Researchers added a stabilising Pro-Gly-Pro sequence to create a more metabolically stable compound. Preclinical research demonstrated nootropic effects, including enhanced learning and memory in various animal models. Studies also revealed neuroprotective properties, with Semax protecting neurons against various forms of damage. Semax received regulatory approval in Russia in the 1990s and has been used clinically there for conditions including stroke rehabilitation, cognitive impairment, and attention disorders. It has been included in Russian treatment guidelines for stroke and optic nerve diseases. Extensive research has been conducted in Russia, though Western peer-reviewed literature remains more limited. The peptide continues to be studied for mechanisms and potential applications.

Mechanism of Action

Semax exerts its effects through multiple mechanisms: **BDNF Upregulation** One of the most significant effects of Semax is increased expression of brain-derived neurotrophic factor (BDNF) and its receptor TrkB. BDNF is crucial for neuroplasticity, neuronal survival, and cognitive function. **NGF and Other Neurotrophins** Semax also increases expression of nerve growth factor (NGF) and other neurotrophic factors, supporting neuronal health and plasticity. **Melanocortin Receptor Effects** While lacking ACTH's hormonal activity, Semax may interact with melanocortin receptors in the brain, which are involved in cognition, motivation, and neuroprotection. **Dopaminergic and Serotonergic Modulation** Research indicates effects on dopamine and serotonin systems, which may contribute to cognitive and mood effects. **Gene Expression Modulation** Semax affects the expression of numerous genes, including those involved in neurotransmitter function, oxidative stress responses, and immune regulation. **Anti-Inflammatory Effects** The peptide has demonstrated anti-inflammatory properties in the brain, potentially contributing to neuroprotection. **Immunomodulation** Semax possesses immunomodulatory effects, influencing cytokine production and immune cell function.

Researched Benefits

Based on preclinical and clinical research findings:

1
Enhanced memory and learning in animal and human studies
2
Neuroprotective effects in stroke and brain injury models
3
Increased BDNF and neurotrophic factor expression
4
Improved attention and focus
5
Potential benefits in optic nerve diseases
6
Anti-inflammatory effects in the CNS
7
Possible mood-stabilising effects

Claim vs Evidence

How popular claims about Semax stack up against the current research, graded using our public evidence grading methodology.

Claim	Evidence	Human evidence?	Regulatory concern	Safer wording
“Improves cognitive function in healthy adults”	C	Limited	Moderate	Russian-language studies report cognitive effects in clinical populations; healthy-adult cognitive-enhancement claims are not well established.
“Neuroprotective after stroke”	C	Yes	Moderate	Approved for stroke recovery in Russia; not UK-licensed for this indication and not on NHS pathways.
“Safer than prescription nootropics”	E	No	High	Comparative safety claims need comparative trials.

Theoretical Dosing & Protocols

⚠️ Educational Only: The following information is derived from research literature and is not a prescription or recommendation. No standardised human dosing exists. Always consult a qualified healthcare professional.

Theoretical Dosage	200-600 mcg intranasally per dose (Russian clinical standard)
Frequency	2-3 times daily
Duration	10-14 days typically, can be extended for certain conditions
Notes	These protocols reflect Russian pharmaceutical use. Semax is not approved in the UK/EU. Intranasal administration is standard. Higher doses (1% solution) may be used for certain conditions in Russia.

Administration Routes

Routes studied in research settings (educational only):

Intranasal (nasal drops or spray - most common)
Subcutaneous injection (less common)

Half-Life	Stability
Short plasma half-life; CNS effects persist longer	Nasal formulations stable under appropriate storage conditions

Safety Profile & Known Risks

Commonly Reported Side Effects

Generally well-tolerated in Russian clinical use
Mild nasal irritation
Headache (rare)
Transient blood pressure changes (rare)

Rare Risks & Concerns

Limited long-term safety data from Western studies
Effects on hormonal systems with chronic use unknown
Potential for drug interactions not fully characterised

Contraindications

Pregnancy and breastfeeding
Active seizure disorders (precautionary)
Known allergy to peptide components
Acute psychosis (precautionary)

UK & EU Regulatory Context

🇬🇧 United Kingdom

Not licensed. Research compound only.

🇪🇺 European Union

Not approved by EMA. Not available as a pharmaceutical.

Semax is approved in Russia and several other countries. It is not approved in Western countries. Products from non-pharmaceutical sources may have quality and authenticity concerns.

Clinical Studies Summary

[The study of chronic partial denervation and quality of life in patients with motor neuron disease treated with semax].

1% semax significantly improves the total estimate of life quality due to the improvement of emotional state and motivation in MND patients with the maximal effect on day 10. This finding suggests that it is feasible to administer 1% semax in complex MND palliative therapy.

Zh Nevrol Psikhiatr Im S S Korsakova. 2007View on PubMed

[The efficacy of semax in the tretament of patients at different stages of ischemic stroke].

Early rehabilitation and administration of semax increase BDNF plasma level, speed functional recovery, and improve motor performance.

Zh Nevrol Psikhiatr Im S S Korsakova. 2018View on PubMed

[Evaluation of therapeutic effect of new Russian drug semax in optic nerve disease].

Addition of semax to therapeutic complex in patients with diseases of the optic nerve had a favorable impact on the intensity and rate of recovery and improved the visual functions.

Vestn Oftalmol. 2000View on PubMed

[Effectiveness of semax in acute period of hemispheric ischemic stroke (a clinical and electrophysiological study)].

It was established that including of Semax in combined intensive therapy of acute ischemic stroke had some influence on the rate of restoration of the damaged neurological functions in terms of increasing the regress of general cerebral and focal, especially motor disorders.

Zh Nevrol Psikhiatr Im S S Korsakova. 1997View on PubMed

Modulation of neuropathological pathways by bioactive peptides and proteins/polypeptides: Targeting oxidative stress in neurodegenerative diseases.

Their multifunctional action profiles and ability to target specific molecular pathways highlight their potential as next-generation neuroprotective agents. However, future clinical validation and advanced strategies are essential for translating these promising molecules into effective treatments.

Neuropeptides. 2025View on PubMed

[POSSIBLE ROLE OF TRANSTHYRETIN IN THE BIOLOGICAL MECHANISM OF THE REGULATORY PEPTIDE NEUROPROTECTION.].

High similarity between the effects of Ttr and coupled molecular systems with the Semax effects in ischemic stroke allowed us to suggest that the neuroprotection mechanisms of Semax (and, possibly, of other neuroprotection mechanisms of Semax) could be mediated by Ttr. In this review, we discussed the role of Ttr in CNS and its possible role in the neuroprotection mechanism of Semax.

Mol Gen Mikrobiol Virusol. 2016View on PubMed

Looking for Semax?

Source research-grade Semax from a trusted UK supplier — third-party tested with certificate of analysis.

View at Supplier

Frequently Asked Questions

Questions to ask a qualified clinician about Semax