Semax History: From ACTH Fragment in Moscow to Unlicensed in the UK

LynxLab · 24 October 2026 · 8 min read

How Semax was designed from ACTH(4-7) in Moscow, what the Russian stroke and optic nerve trials reported, and why it holds no licence in the UK, EU or US.

Photo: cottonbro studio, Pexels

Semax is a seven-amino-acid peptide, Met-Glu-His-Phe-Pro-Gly-Pro, built in Moscow in the 1980s from a fragment of the stress hormone ACTH. In Russia it is a registered medicine. In the UK, the EU and the US no regulator has ever assessed it, and it is sold only as a laboratory chemical. The history explains both facts, so this post follows semax from the original design through the stroke and optic nerve trials to its legal position today.

The sequence: ACTH(4-7) with a Pro-Gly-Pro tail

Adrenocorticotropic hormone, ACTH, is a 39-amino-acid hormone released by the pituitary gland. From the 1960s the Dutch pharmacologist David de Wied showed that short fragments of ACTH, too small to act on the adrenal glands, still changed how rats learned and forgot. The fragment that drew most attention was ACTH(4-10), Met-Glu-His-Phe-Arg-Trp-Gly.

The weakness of ACTH(4-10) was durability. Peptidases in blood and tissue cut it apart in minutes. The Moscow chemists kept the first four residues, ACTH(4-7), and replaced the Arg-Trp-Gly ending with the tripeptide Pro-Gly-Pro.

A 2020 paper in Genes from the same institute states the reason plainly: the Pro-Gly-Pro tail "was included to ensure the resistance of Semax to peptidases" (Filippenkov et al., Genes, 2020). The semax peptide sold for research today has exactly this seven-residue sequence, written ACTH(4-7)PGP in the Russian literature.

Who designed it and where

Semax came out of two Moscow institutions working together. The chemistry was done at the Institute of Molecular Genetics of the Russian Academy of Sciences, on Kurchatov Square, under Nikolai Myasoedov. The physiology and behavioural testing came from the Department of Human and Animal Physiology at Moscow State University, under Igor Ashmarin.

Both names appear on almost every Semax paper from the 1990s onward, and Myasoedov is still a co-author on the 2020 transcriptome work. A 1997 review by Ashmarin, Nezavibat'ko and Myasoedov in the Pavlov Journal of Higher Nervous Activity carried the subtitle "15 years of development and study", which dates the start of the project to around 1982.

What the Moscow stroke trials reported

The neurologists Evgeny Gusev and Veronika Skvortsova ran the first clinical series. In 1997 they described 30 patients in the acute phase of hemispheric ischaemic stroke who received Semax alongside standard intensive care, compared with 80 control patients matched for stroke severity and location.

Outcomes were clinical rating scales, EEG mapping and somatosensory evoked potentials. The authors reported faster regression of general cerebral and focal deficits, especially motor deficits, and named 12mg a day for moderate strokes and 18mg a day for severe strokes, over courses of 5 and 10 days, as the most effective regimens (Gusev et al., Zhurnal Nevrologii i Psikhiatrii, 1997).

Two decades later Gusev's group returned with 110 post-stroke patients, 43 men and 67 women with a mean age of 58. Patients were split into early and late rehabilitation groups, then each was split into a Semax and a no-Semax subgroup. Semax was given as two 10-day courses of 6000 mcg a day with a 20-day gap.

Plasma BDNF, a growth factor for neurons, rose in the Semax subgroups and stayed high through the study, and Barthel index scores for daily living improved faster (Gusev et al., Zhurnal Nevrologii i Psikhiatrii, 2018). Neither study was placebo-controlled or blinded as far as the abstracts state, and both came from the group most invested in the drug. A reader used to NICE or FDA standards would file them as supportive, not conclusive.

The optic nerve and glaucoma studies

Semax also went to the eye clinic. A team led by G. S. Polunin treated patients with vascular, toxic-allergic and inflammatory optic nerve disease, and partial optic atrophy, with a product the paper calls "Semax 0.1%" alongside standard neurotrophic and anti-inflammatory therapy.

Patients were split into three groups: nasal drops, endonasal electrophoresis, and a control group on standard therapy alone. The authors reported better visual acuity, wider visual fields, higher electrical sensitivity and conductivity of the optic nerve, and improved colour vision in the treated groups (Polunin et al., Vestnik Oftalmologii, 2000).

The following year Kurysheva and colleagues reported on glaucoma patients whose eye pressure had already been brought to normal. Adding Semax to a neuroprotective regimen gave better electrophysiological results than the traditional regimen alone (Kurysheva et al., Vestnik Oftalmologii, 2001). Neither abstract gives patient numbers, and neither finding has been reproduced outside Russia.

One detail is constant across the clinical record. Every human study used the nose as the route, as drops or electrophoresis, which is how the Russian product is made. That is why the compound is often described as a semax nasal peptide in the research literature, and why there is no published human data for any other route.

What Russian registration means, and what it does not

In Russia Semax is a registered medicine. A 2022 review of Russian peptide pharmaceuticals in the journal Pharmaceutics lists it third in a table of 14 original Russian peptide drugs, with its clinical group given as "nootropic drug" (Deigin et al., Pharmaceutics, 2022). Its neighbours in that table include Dalargin, Thymogen and Noopept, none of which is licensed in Britain either.

Registration in one country rests on trials reviewed by that country's regulator. It does not travel. The MHRA, the EMA and the FDA each run their own assessment against their own evidence standards, and a Russian dossier built on open-label Moscow studies would not meet them without new trials.

The Russian literature itself does not claim otherwise. The 2020 Genes paper, after describing Semax as a drug used "successfully in the treatment of patients with severe impairment of cerebral blood circulation", adds that "its molecular mechanisms of action within the brain are not yet fully understood". The sibling post on this site covers what the BDNF and nootropic studies measured and how far they go.

Why Semax has no licence in the UK, EU or US

In the UK a product needs a marketing authorisation from the MHRA before it can be sold as a medicine. The MHRA's own guidance states that "unlicensed medicines do not have a marketing authorisation in the UK and may not have been assessed by the MHRA" (MHRA, Supply unlicensed medicinal products, updated 2025). Semax has never held a UK authorisation, so it cannot be prescribed or sold as a medicine here.

The US position is spelled out in more detail. The FDA has placed "Semax (heptapeptide)" in category 2 of its list of bulk substances nominated for pharmacy compounding, the category for substances that "may present significant safety risks". The agency's stated reason is that compounded Semax "may pose risk for immunogenicity for certain routes of administration due to the potential for aggregation and peptide-related impurities", and that it "has no, or limited, safety-related information for proposed routes of administration" (FDA, Certain Bulk Drug Substances, category 2).

There is no EU-wide authorisation through the EMA either. The practical consequence for anyone who wants to buy semax in Britain is that the vial is a research chemical. It comes with a lab report, not a patient information leaflet, and the research-use-only label is a legal description rather than a marketing line.

LynxLab stocks semax 10mg for research use at £24.99 a vial, tested to 99% purity, with the certificate of analysis on the product page.

How the record looks to a sceptical reader

The Semax literature is large in count and narrow in origin. Almost every clinical paper comes from Moscow, most are in Russian with English abstracts, and the two institutions that designed the peptide are co-authors on the mechanism work as well as the trials.

That does not make the findings wrong. Peptidase-resistant ACTH fragments are a reasonable idea, and the stroke series ran for 20 years with consistent direction of effect. It does mean that the questions a UK or EU regulator would ask, about randomisation, blinding, placebo, sample size and independent replication, have not been answered.

For laboratories working with semax uk suppliers, that gap is the research opportunity. The design is forty years old and the evidence base is still waiting for its first independent, blinded trial.

Frequently asked questions

Is Semax approved anywhere?

Yes, in Russia, where a 2022 review in Pharmaceutics lists it among 14 original Russian peptide drugs as a nootropic. It has no marketing authorisation from the MHRA, the EMA or the FDA, and the FDA has placed it in category 2 of its compounding list on safety-information grounds.

Is Semax legal in the UK?

Semax is not a controlled substance in the UK, and it can be sold as a chemical for laboratory research. It is not a licensed medicine, so it cannot be sold, prescribed or advertised for human use, which is why UK suppliers label it research use only.

What was Semax originally developed for?

It was designed in Moscow as a peptidase-resistant analogue of ACTH(4-10), a hormone fragment known since the 1960s to affect learning in rats. Its first clinical use in Russia was in acute ischaemic stroke, reported by Gusev and Skvortsova in 1997, followed by optic nerve disease and glaucoma studies in 2000 and 2001.

Who invented Semax?

Semax came from the Institute of Molecular Genetics of the Russian Academy of Sciences, under the chemist Nikolai Myasoedov, working with Igor Ashmarin's physiology department at Moscow State University. A 1997 review by the group described 15 years of development, which puts the start of the work around 1982.

Sources

Research use only

Semax from LynxLab

10mg vials from £24.99. ≥99% purity, lab report on the page. Same-day dispatch, UK stock.

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