Last updated 11 October 2026 · SARMs Store editorial team. Products on this site are supplied strictly for laboratory research and are not for human consumption. This guide summarises published research; it is not medical advice and contains no instructions for use. 18+ only.
Semax at a glance
| Class | Heptapeptide analogue of ACTH fragment 4-10 (Met-Glu-His-Phe-Pro-Gly-Pro) |
|---|---|
| Developed by | Institute of Molecular Genetics, Russian Academy of Sciences, 1980s to 1990s |
| Highest evidence | Licensed in Russia as a nasal solution for stroke and cognitive complaints; Russian clinical studies, few in English-language journals |
| Studied for | Neuroprotection after stroke, attention and memory tasks, BDNF expression in rodents |
| Format | Lyophilised vial (5mg) |
| Storage | 2 to 8°C unopened, away from light |
| UK status 2026 | Research chemical; not a UK-licensed medicine; not named on the WADA list |
What Semax is
Semax is a seven-amino-acid peptide based on the 4-10 fragment of adrenocorticotropic hormone with a proline-glycine-proline tail added to slow breakdown. It was developed at the Institute of Molecular Genetics in Moscow and has been a licensed medicine in Russia since the 1990s, sold as nasal drops. It has no hormonal activity of ACTH; the fragment was chosen because it affects attention and memory in animal tests without raising cortisol.
Semax UK: what buyers should know
Semax is one of the most searched nootropic peptides in the UK, and most of those searches are for "semax nasal spray". That is because Semax is licensed in Russia as a nasal solution, and that is the form most people read about. Research vials are the same peptide in lyophilised (freeze-dried) form, which keeps far longer than a made-up solution. Our Origin Peptides Semax 5mg is a sealed, batch-numbered vial dispatched from our UK warehouse at £25.
Semax nasal spray vs Semax vials
| Nasal solution (Russia) | Research vial | |
|---|---|---|
| Form | Ready-made 0.1% or 1% solution | Lyophilised powder, 5mg per vial |
| Shelf life | Short once opened | Long when sealed and refrigerated |
| Licensed | In Russia and some CIS countries | No, supplied for laboratory research |
| Availability in the UK | Not licensed or sold as a medicine | Stocked and dispatched from the UK |
Semax names you will see
Semax appears as Semax, Semaks, ACTH (4-10) analogue and by its sequence Met-Glu-His-Phe-Pro-Gly-Pro. N-acetyl Semax and N-acetyl Semax amidate (NA-Semax-Amidate) are modified versions sold by some suppliers; they are different molecules from standard Semax and should be labelled as such.
Semax and Selank together
Semax and Selank were both developed at the Institute of Molecular Genetics in Moscow and are often bought together. Semax comes from the ACTH fragment research and is studied for attention, memory and neuroprotection; Selank comes from tuftsin and is studied for anxiety-like behaviour. Both are £25 for a 5mg vial, and the multibuy discount applies when they are ordered together. Both are Russian-licensed nasal medicines with similar evidence gaps outside Russia.
What the research found
Russian clinical use. Semax is registered in Russia for ischaemic stroke, optic nerve disease and, at lower strength, for cognitive complaints and attention. The supporting trials are mostly Russian-language, open-label or small, and have not been repeated in Western regulatory trials. A number are indexed in PubMed as abstracts.
Mechanism studies. Rodent work from Dolotov, Grivennikov and colleagues reported that Semax increases expression of brain-derived neurotrophic factor (BDNF) and its receptor TrkB in the hippocampus, which is the basis of the neuroprotection hypothesis. Other rodent studies reported effects on the serotonin and dopamine systems and on anxiety-like behaviour.
What is missing. No English-language, placebo-controlled trial in healthy adults for attention, memory or mood has been published. Claims about cognitive enhancement in healthy people rest on animal data and Russian clinical reports.
Stability, storage and handling
Supplied lyophilised in a sealed vial. Keep unopened vials at 2 to 8 degrees Celsius or frozen for long storage, away from light. Reconstituted solutions degrade over days to weeks. The certificate should show HPLC purity and mass spectrometry identity.
Legal status in the UK, 2026
Not a controlled substance under the Misuse of Drugs Act 1971. It holds no UK or EU marketing authorisation, so in the UK it is not a licensed medicine and cannot be sold or advertised for human use; supplied strictly for laboratory research. It is not named on the WADA Prohibited List.
What to check before buying
Milligrams per vial, HPLC purity, mass spectrometry identity, a batch number matching the certificate, and cold-chain shipping. Every Origin Peptides batch is independently tested and its certificate of analysis is published on the product page and the Lab Testing page.
Frequently asked questions
Is Semax a licensed medicine?
In Russia, yes, as nasal drops. Not in the UK, the EU or the US.
Does Semax raise cortisol?
The fragment was chosen because it lacks the hormonal activity of ACTH; animal studies do not report a cortisol rise.
What is the difference between Semax and Selank?
Semax is an ACTH fragment analogue studied for attention and neuroprotection; Selank is a tuftsin analogue studied for anxiety.
Is Semax legal in the UK?
Legal to buy and possess as a research compound; not lawful to sell or advertise for human consumption.
Can you buy Semax in the UK?
Yes, as a research peptide. Our Semax 5mg vial is stocked and dispatched from the UK.
Do you sell Semax nasal spray?
No. We supply Semax as a lyophilised 5mg vial, which keeps longer than a ready-made solution.
Is N-acetyl Semax the same as Semax?
No. It is a modified version of the peptide and should be labelled separately.
Key references
Dolotov OV, Karpenko EA, Inozemtseva LS, et al. Semax, an analog of ACTH(4-10) with cognitive effects, regulates BDNF and trkB expression in the rat hippocampus. Brain Research. 2006;1117(1):54-60. Kaplan AY, Kochetova AG, Nezavibathko VN, Rjasina TV, Ashmarin IP. Synthetic ACTH analogue Semax displays nootropic-like activity in humans. Neuroscience Research Communications. 1996;19(2):115-123. Gusev EI, Skvortsova VI, et al. Semax in the treatment of acute ischaemic stroke (Russian clinical series, various, 1997 to 2005).
Related guides
- Selank research guide
- SARMs vs peptides: what the research compares
- How to read a certificate of analysis
- SARMs 101 hub
Research products: Origin Peptides Semax 5mg · Selank 5mg · Full Origin Peptides range · Lab Testing