Semax is a synthetic peptide derived from the ACTH(4-7) fragment of adrenocorticotropic hormone. It is studied as a nootropic and neuroprotective compound and is used as a prescription intranasal medicine in a few countries, such as Russia.

What does research suggest Semax does?

Research discusses Semax in relation to cognition, attention, mood, and neuroprotection, with proposed mechanisms including modulation of BDNF and neurotrophic signalling. Much of this evidence is preclinical or from regional human studies that have not been widely independently replicated.

Is Semax approved or legal?

Semax is approved and prescribed as a medicine in some countries, including Russia, but it is not approved by regulators in the EU or the United States. Its legal status varies by jurisdiction, and outside its regions of approval it is generally treated as an unapproved research chemical.

Where it is used clinically, Semax is a prescribed intranasal product with a reported safety profile in that setting. However, human safety data outside those regions is limited, and material from the research-chemical market is unverified for purity and identity.

What are the reported side effects of Semax?

The most commonly reported side effect with intranasal use is nasal irritation. Its broader and long-term safety profile has not been well characterized in independent, large-scale studies.

How does Semax compare to Selank?

Semax and Selank are related synthetic peptides often discussed together. Semax is studied mainly for cognitive and neuroprotective effects, while Selank is studied for anxiolytic (anti-anxiety) effects. Both are approved regionally but not in the EU or US.

How is Semax related to a natural hormone?

Semax is a synthetic short peptide based on a fragment of ACTH (adrenocorticotropic hormone), specifically the ACTH(4-7) region, with modifications intended to keep the neurological activity while stripping away the hormonal effect on the adrenal glands. So although it is derived from a hormone fragment, it is designed not to act like the parent hormone. This is background chemistry, not a health claim.

How does Semax differ from Selank, which it is often mentioned alongside?

They come from different origins: Semax is derived from an ACTH fragment and is usually discussed in a cognitive or neuroprotective context, while Selank is derived from the immune peptide tuftsin and is more often discussed around anxiety. Both were developed in Russia, both are used regionally as intranasal medicines, and both have limited independent replication elsewhere. Being frequently compared does not make them interchangeable.

Why does Semax's regulatory status look so different depending on the country?

Semax was developed and registered within Russia, where it has been used as a prescription medicine, but that domestic approval does not transfer to other regions. In the EU and US it has never been approved as a medicine, so material sold internationally typically falls under a research-chemical label with no regulatory oversight of quality or purity. A drug being approved somewhere is not evidence that it is approved, or verified, where you are.

Where can I buy Semax and compare vendors?

Use the vendor comparison on this page. It shows only checked, product-specific links and identifies vendor claims, independent documentation and affiliate relationships separately. Availability and legal status can vary by country.

Cognitive

Buy Semax – Vendors, Prices, Testing and Evidence

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Also known as: ACTH(4-7) analogue

Evidence grade C — Early / Preclinical

Short answer

A peptide discussed for cognitive and neuroprotective effects. Approved in some jurisdictions but not others.

Where can you buy Semax?

Crystal Peptides. The table lists only product-specific offers that were checked and for which a real destination exists. Missing prices, quantities, stock and laboratory details are not inferred.

What is known?

Semax is a synthetic peptide derived from an ACTH fragment, studied for nootropic and neuroprotective effects.

What is not established?

Some human studies exist in the countries where it is used clinically; broader independent replication is limited.

Safety

Where used clinically it is intranasal and prescribed; research-market use is unverified.

Regulatory status

Approved/used as a medicine in some countries (e.g. Russia); not approved in the EU/US.

Not medical advice. This educational reference is not diagnosis, treatment, prescribing, dosing or emergency guidance. Consult a qualified professional before making health-related decisions.

Vendor comparison

Buy Semax: compare vendors

The table lists only product-specific offers that were checked and for which a real destination exists. Missing prices, quantities, stock and laboratory details are not inferred.

Vendor	Product	Documentation	Shipping	Checked	Action
Crystal Peptides Code PEPTIDES10 −10% · discount code details Sponsored	Semax research product	Vendor-supplied data COA stated as available Not independently documented	Europe See the localized country store	Jul 18, 2026	View at vendor

Crystal Peptides

Semax research product

Code PEPTIDES10 −10% · discount code details

What is it?

Semax is a synthetic peptide derived from an ACTH fragment, studied for nootropic and neuroprotective effects.

Research and evidence

Semax is a synthetic peptide derived from a fragment of adrenocorticotropic hormone (ACTH), specifically the ACTH(4-7) sequence modified to improve stability. It is most often discussed as a nootropic and neuroprotective compound, and it occupies an unusual position in the peptide landscape: it is approved and prescribed as a medicine in a small number of countries, most notably Russia, while remaining unapproved in the European Union and the United States. On peptides.cx it is categorized as a cognitive peptide, and the honest evidence picture is best described as regionally established but not yet broadly validated outside its areas of clinical use.

Semax is researched primarily for its proposed effects on attention, learning, mood, and the protection of neural tissue under stress or ischemic conditions. The mechanisms most frequently cited in the literature include modulation of brain-derived neurotrophic factor (BDNF) and related neurotrophic signalling, alongside broader neuroprotective pathways. It is important to distinguish the strength of the evidence behind these ideas. Much of the neuroprotective and cognitive-enhancement data comes from preclinical animal studies, while human data exists mainly within the countries where Semax is used clinically as an intranasal formulation. Independent replication of those human findings in large Western trials remains limited, which is why Semax carries a mid-tier evidence grade rather than a strong one.

Anyone researching Semax should treat it as an educational and scientific subject rather than a validated over-the-counter supplement. Where it is used clinically, it is a prescribed, intranasally administered medicine; material sold on the research-chemical market is not quality-controlled, and its purity and identity are unverified. It is frequently compared and discussed alongside Selank, a related peptide studied for anxiolytic rather than cognitive effects. This page summarizes what Semax is, why it is studied, and what the current evidence does and does not support, without offering medical advice, dosing guidance, or purchasing recommendations.

Evidence grade: C

Some human studies exist in the countries where it is used clinically; broader independent replication is limited. Preclinical work reports neuroprotective and cognitive effects.

Human evidence

Some human studies exist in the countries where it is used clinically; broader independent replication is limited.

Animal and preclinical evidence

Preclinical work reports neuroprotective and cognitive effects.

Proposed mechanisms

Discussed modulation of BDNF
Proposed neuroprotective signalling

Safety concerns and known side effects

Where used clinically it is intranasal and prescribed; research-market use is unverified.

Nasal irritation with intranasal use reported

Regulatory status

Approved/used as a medicine in some countries (e.g. Russia); not approved in the EU/US.

Semax research timeline

1980s
Semax is developed in Russia at the Institute of Molecular Genetics and Moscow State University as a synthetic analogue of the ACTH(4-10) fragment, designed to keep behavioural/neurotropic activity while removing the hormone's classic corticotropic effects.
1990s
Preclinical work in Russia describes neuroprotective and cognition-related effects and reports that the peptide is resistant to rapid breakdown, and it moves toward domestic clinical use as an intranasal formulation.
Late 1990s to 2000s
Semax is registered and used as a medicine within Russia for indications discussed in the local literature (such as stroke recovery and cognitive complaints); it does not gain approval in the EU or US.
2000s to 2010s
Mechanistic studies, largely from the originating research groups, explore proposed effects on BDNF and other neurotrophic signalling, though broad independent replication outside these groups remains limited.
Early 2020s
Semax and its N-acetyl variant become widely discussed in international nootropic communities and sold on the research-chemical market, well outside any clinical approval and without verified purity.

Frequently asked questions about Semax

What is Semax?: Semax is a synthetic peptide derived from the ACTH(4-7) fragment of adrenocorticotropic hormone. It is studied as a nootropic and neuroprotective compound and is used as a prescription intranasal medicine in a few countries, such as Russia.
What does research suggest Semax does?: Research discusses Semax in relation to cognition, attention, mood, and neuroprotection, with proposed mechanisms including modulation of BDNF and neurotrophic signalling. Much of this evidence is preclinical or from regional human studies that have not been widely independently replicated.
Is Semax approved or legal?: Semax is approved and prescribed as a medicine in some countries, including Russia, but it is not approved by regulators in the EU or the United States. Its legal status varies by jurisdiction, and outside its regions of approval it is generally treated as an unapproved research chemical.
Is Semax safe?: Where it is used clinically, Semax is a prescribed intranasal product with a reported safety profile in that setting. However, human safety data outside those regions is limited, and material from the research-chemical market is unverified for purity and identity.
What are the reported side effects of Semax?: The most commonly reported side effect with intranasal use is nasal irritation. Its broader and long-term safety profile has not been well characterized in independent, large-scale studies.
How does Semax compare to Selank?: Semax and Selank are related synthetic peptides often discussed together. Semax is studied mainly for cognitive and neuroprotective effects, while Selank is studied for anxiolytic (anti-anxiety) effects. Both are approved regionally but not in the EU or US.
How is Semax related to a natural hormone?: Semax is a synthetic short peptide based on a fragment of ACTH (adrenocorticotropic hormone), specifically the ACTH(4-7) region, with modifications intended to keep the neurological activity while stripping away the hormonal effect on the adrenal glands. So although it is derived from a hormone fragment, it is designed not to act like the parent hormone. This is background chemistry, not a health claim.
How does Semax differ from Selank, which it is often mentioned alongside?: They come from different origins: Semax is derived from an ACTH fragment and is usually discussed in a cognitive or neuroprotective context, while Selank is derived from the immune peptide tuftsin and is more often discussed around anxiety. Both were developed in Russia, both are used regionally as intranasal medicines, and both have limited independent replication elsewhere. Being frequently compared does not make them interchangeable.
Why does Semax's regulatory status look so different depending on the country?: Semax was developed and registered within Russia, where it has been used as a prescription medicine, but that domestic approval does not transfer to other regions. In the EU and US it has never been approved as a medicine, so material sold internationally typically falls under a research-chemical label with no regulatory oversight of quality or purity. A drug being approved somewhere is not evidence that it is approved, or verified, where you are.
Where can I buy Semax and compare vendors?: Use the vendor comparison on this page. It shows only checked, product-specific links and identifies vendor claims, independent documentation and affiliate relationships separately. Availability and legal status can vary by country.

Common discussion areas

FocusMoodComparison with Selank

Compare Semax

Semax vs Selank

Sources

Editorial review and transparency

Written by: peptides.cx Editorial Team
Scientific reviewer: No named medical reviewer is currently assigned
Last editorial review: June 1, 2026
Last vendor check: July 18, 2026
Review method: Source review, claim verification, vendor-data separation and regulatory-context review.
Commercial disclosure and conflicts: Vendor relationships do not determine evidence or safety ratings. No named reviewer conflict is recorded because no named reviewer is assigned.

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