Encyclopedia entry

Semax

Evidence: Mixed evidence

Oliver Mackman · Editorial director · Best Business Loans Ltd (16833937)

Last updated 2026-06-04

Editorial with affiliate links. We earn from purchases via outbound retailer / clinic links. How we are funded.

AI-friendly summary · Semax

Semax is a synthetic 7-amino-acid peptide developed by the Institute of Molecular Genetics of the Russian Academy of Sciences. It is based on residues 4 to 10 of adrenocorticotropic hormone (ACTH), extended by a Pro-Gly-Pro sequence to increase metabolic stability. It is registered in Russia for stroke recovery and certain cognitive and vascular conditions. Outside Russia, including in the UK and the broader EU, Semax has no marketing authorisation from any regulator.

Semax: a 7-amino-acid synthetic analog of ACTH (4-10). Registered as a pharmaceutical in Russia for stroke recovery and cognitive indications. Not licensed by MHRA or EMA. Research use only in the UK.

Mechanism of action

How Semax works

Semax is derived from the 4-10 fragment of adrenocorticotropic hormone (ACTH), extended at the C-terminus by a Pro-Gly-Pro sequence to slow enzymatic degradation. The proposed mechanism involves modulation of brain-derived neurotrophic factor (BDNF) expression, effects on the cholinergic and serotonergic systems, and a neuroprotective profile observed in rodent ischaemia models. The exact receptor target in humans is not definitively established. The mechanism underlying the stroke-recovery indication in Russia has not been characterised to the standard required by EMA or FDA submissions.

Source: Institute of Molecular Genetics, Russian Academy of Sciences

What the Russian clinical literature shows

Semax has roughly 60 to 80 peer-reviewed papers indexed on PubMed, the majority from the originating Russian research group. The compound holds Russian pharmaceutical registration as an intranasal preparation for stroke recovery and certain cognitive indications. As with Selank, the clinical evidence base by western regulatory standards is methodologically limited: small single-site trials, predominantly Russian-language publications, designs that pre-date current ICH-GCP standards.

· Animal studies from the Russian Academy of Sciences reported neuroprotective effects in rodent models of ischaemia and memory impairment.
· Russian clinical studies examined Semax in stroke recovery settings as an intranasal preparation, supporting the domestic regulatory submission.
· Some papers report brain-derived neurotrophic factor (BDNF) modulation in animal models, forming part of the mechanistic rationale.
· The Russian clinical dossier supported registration as an intranasal pharmaceutical for neurological indications within Russia.
· As with Selank, clinical studies generally used designs and sample sizes that would not meet current FDA, EMA, or MHRA standards for a marketing authorisation application.
· Russian pharmacy availability does not constitute evidence of efficacy by western regulatory standards, and Russian registration does not apply in the UK or EU.

Sister compound: Selank (see Selank encyclopedia entry) is a separate Russian-developed peptide with a different mechanism, targeting anxiolytic rather than neuroprotective indications, often discussed alongside Semax.

UK regulatory status

Semax sits outside the Misuse of Drugs Act 1971 and outside the Psychoactive Substances Act 2016. It holds no UK or EU marketing authorisation as a medicine. Russian pharmaceutical registration does not apply in either jurisdiction. UK retailers can sell it lawfully only by labelling it for "research use only" and avoiding any therapeutic claim.

· Not a controlled drug under the Misuse of Drugs Act 1971.
· Not scheduled under the Psychoactive Substances Act 2016.
· No MHRA marketing authorisation as a medicine in the UK.
· Not authorised by the EMA for use in any EU member state.
· Russian registration does not apply in the UK or EU regulatory jurisdictions.
· Sold legally as a research chemical by UK retailers when marketed without therapeutic claims.
· Becomes an unlicensed medicinal product the moment a retailer or commentator makes therapeutic claims about it.

Risks and unknowns

What the literature does not yet show about Semax

Known concerns

Clinical evidence base is methodologically limited by western regulatory standards. Single-jurisdiction clinical dossier.
Russian pharmaceutical registration does not equate to MHRA or EMA approval. Independent replication outside the originating institution is limited.
Purity of UK research-peptide supply varies between retailers. CoA gating and HPLC analysis differ.
The stroke-recovery indication in Russia was registered under different regulatory requirements than those of EMA or MHRA.

Open questions in the literature

The precise receptor target and full mechanism in humans has not been characterised to western regulatory standards.
Whether the Russian stroke-recovery signal would replicate in a modern ICH-GCP randomised trial is unknown.
Long-term safety in non-stroke populations using the compound for off-indication cognitive purposes is not characterised.
Interactions with western-licensed cardiovascular and neurological medications have not been formally studied.

Regulatory note

Not a controlled drug under the Misuse of Drugs Act 1971. Not scheduled under the Psychoactive Substances Act 2016. No UK or EU marketing authorisation as a medicine. Russian registration does not apply in the UK. Becomes an unlicensed medicinal product the moment a retailer or commentator makes therapeutic claims about it.

Important: PeptideClear publishes encyclopedia commentary only and does not recommend human use. Speak to a UK-registered prescriber before any medical decision.

Where to learn more

· PubMed search: Semax returns Russian-authored preclinical and clinical papers.
· PubMed: Semax ischaemia for the neuroprotection literature.
· Sister compound: Selank encyclopedia entry.
· UK retailer purity comparison: research peptides UK retailers.

Frequently asked questions

Is Semax legal in the UK?

Semax is not a controlled drug under the Misuse of Drugs Act 1971 and is not scheduled under the Psychoactive Substances Act 2016. It is sold legally by UK research peptide retailers under "research use only, not for human or animal consumption" framing. It holds no UK marketing authorisation as a medicine.

What does the human evidence show for Semax?

Russian clinical studies have examined Semax in stroke recovery settings as an intranasal preparation. These studies supported the domestic Russian regulatory submission. The clinical designs and sample sizes generally would not meet current FDA, EMA, or MHRA standards for a marketing authorisation application. No EMA or FDA filing has been made.

What is the regulatory status of Semax in the UK?

Semax has no MHRA marketing authorisation as a medicine in the UK and no EMA authorisation in the EU. Russian pharmaceutical registration does not apply in either jurisdiction. Sold as a research chemical when marketed without health claims, but becomes an unlicensed medicinal product the moment a retailer or commentator makes therapeutic claims.

What forms is Semax available in?

In Russia, Semax is registered as a nasal-spray pharmaceutical for stroke and neurological indications. UK research peptide retailers list it most commonly as lyophilised powder in 1mg or 10mg vials for reconstitution. Some retailers offer pre-mixed nasal sprays. PeptideClear publishes no dosing or human-use instructions.

Where can I learn more about Semax?

A PubMed search for "Semax" returns Russian-authored preclinical and clinical papers, some available in English translation or published in English-language journals. The Institute of Molecular Genetics (Russian Academy of Sciences) is the primary research source. The "Where to learn more" section links to the available primary sources.

Where to buy Semax in the UK

Compare UK research-peptide retailers stocking Semax, with current prices and CoA status. Research use only, not for human or animal consumption.

Compare Semax prices

Clinical evidence record

Read the clinical evidence record for Semax

Top peer-reviewed citations, mechanism of action, structured UK regulatory status. Machine-readable companion to this encyclopedia entry.

Popular on PeptideClear

Research peptides

BPC-157 (UK)

Collagen

Best UK collagen brands 2026

GLP-1

UK GLP-1 clinics compared

Methodology

CoA Trust Index

Shop

BPC-157 UK prices

Ready to buy

Buy Semax in the UK

UK retailers compared by price, Trust Index, and CoA practice. Editorial commentary only. Research use only.

Buy Semax in the UK CoA Trust Index