In short
Selank is a synthetic heptapeptide built on tuftsin, a short immune peptide, and extended by a Pro-Gly-Pro sequence that protects it from enzymatic breakdown. Its published literature is small, concentrated in a few Moscow institutes and largely preclinical. The essentials:
- Sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro, formula C33H57N11O9, molecular weight 751.9 Da (PubChem CID 11765600)
- PubMed lists 68 records with Selank in the title or abstract, 39 of them in English (query of 8 October 2026)
- Only 3 records are indexed as clinical trials, all in Russian, with 60 to 70 patients each
- Not approved as a medicine in the EU or the US, supplied only as reference material for laboratory research
This guide covers the single molecule. For the side-by-side with its sister peptide, see Semax vs Selank.
What is Selank?
Selank is a seven-residue peptide, Thr-Lys-Pro-Arg-Pro-Gly-Pro, developed at the Institute of Molecular Genetics of the Russian Academy of Sciences. The first four residues are tuftsin, the last three are a stabilising tail. Its molecular weight is 751.9 Da, and it contains neither cysteine nor methionine, the two residues most prone to oxidation in peptide chemistry.
That mass is the practical anchor for any laboratory, because a mass spectrometry identity check is compared against it. Without cysteine there are also no disulfide bridges, which makes Selank chemically simpler to handle than many larger peptides.
Russian sources class Selank as a peptide anxiolytic. Read that label as the research context in which the molecule was developed, not as an established effect. Sequence and the current batch certificate are on the Selank peptide product page.
From tuftsin to Selank: why the sequence needed a stabiliser
Tuftsin, the tetrapeptide Thr-Lys-Pro-Arg, was described in 1970 as a natural peptide that stimulates phagocytosis. It is cleaved from the heavy chain of immunoglobulin G and is short-lived in biological fluids, which limits its use in controlled experiments. Selank keeps the four tuftsin residues and adds a C-terminal Pro-Gly-Pro extension that peptidases attack far less readily.
The original description appeared in Nature (Najjar and Nishioka 1970). Tuftsin has since become a scaffold for a whole family of analogues, and a 2017 review catalogued 86 documents on the parent peptide and its derivatives (Siebert 2017, Curr Med Chem).
Selank is the branch of that family that moved into neuroscience. Bonds next to proline are poor substrates for most peptidases, so the extended molecule survives long enough to be studied. The same tail stabilises Semax. A 2018 review from the developing institute summarises the molecular work on this design (Vyunova 2018, Protein Pept Lett).
What has the published research on Selank examined?
The usable literature falls into four strands: gene expression in the GABAergic system, receptor binding, immune gene expression inherited from tuftsin, and behavioural models of withdrawal. Almost all of it is preclinical. The table lists representative studies with model and scale, so that each finding can be read in its own context.
| Research question | Model and scale | Reported finding | Reference |
|---|---|---|---|
| Neurotransmission genes | Rat frontal cortex, 84 genes | 45 genes changed at 1 h, 22 at 3 h | Volkova 2016 |
| Same gene panel in vitro | IMR-32 neuroblastoma cells | No mRNA change with Selank alone | Filatova 2017 |
| GABA receptor binding | Brain membranes, radioligand assay | Positive allosteric modulation | Vyunova 2018 |
| Inflammation genes | Mouse spleen, 84 genes | 34 genes changed | Kolomin 2011 |
| Ethanol and memory | Rats, 30 weeks of ethanol | Ethanol-induced BDNF rise prevented | Kolik 2019 |
| Morphine withdrawal | Rats, naloxone model | Withdrawal index down 39.6 %, diazepam 49.3 % | Konstantinopolsky 2022 |
| Route of administration | Two mouse strains, two routes | Effects only in BALB/c, profile differed by route | Vasil’eva 2016 |
Two details deserve emphasis. The in vitro follow-up by the same group found no direct effect of Selank alone on the GABAergic genes, which tempers the in vivo result. And the route comparison found that intraperitoneal Selank increased GABA receptor binding sites by 38 %, while intranasal Selank increased NMDA receptor binding by 23 %. Route is a variable, not a detail, as our comparison of Semax and Selank explains.
How large and how reliable is the evidence base?
Small and narrow. A PubMed search restricted to title and abstract returned 68 records on 8 October 2026, 39 in English and only 7 published since 2020. Three are indexed as clinical trials, all Russian-language and sharing co-authors from the developing institute, with 60 to 70 patients each. No European or American regulator has assessed any of them.
| Clinical record | Design | n |
|---|---|---|
| Zozulia 2008 | Selank vs medazepam | 62 |
| Medvedev 2014 | Selank vs phenazepam | 60 |
| Medvedev 2015 | Phenazepam with or without Selank | 70 |
The investigators reported anxiolytic effects comparable to the benzodiazepine comparators. These are their conclusions from small designs in a national journal, not replicated outside that network.
Independent Western literature mostly comments rather than replicates. A 2021 review called Selank one of the “poorly studied Russian drugs with GABAergic mechanisms” (Doyno 2021, J Clin Pharmacol). The most ambitious human work used resting-state fMRI in 52 healthy participants to compare Selank, Semax and placebo (Panikratova 2020, Dokl Biol Sci).
What should a Selank certificate of analysis show?
Four items: the batch number that matches the vial, the analysis date, HPLC purity with the chromatogram, and mass spectrometry identity at 751.9 Da. Purity and content are different numbers. Purity describes how much of the peptide material is Selank, content describes how much of the powder in the vial is peptide at all.
A real certificate shows the difference. The current Molequa® Selank batch, ATSEL-10-2507-01, was analysed by the independent laboratory Analyton Labs: RP-HPLC purity 99.07 % and 9.87 mg of peptide in a vial labelled 10 mg. Both figures are correct, and they answer different questions.
N-acetyl Selank is a different molecule with an acetylated N-terminus and a different mass. A certificate issued for one form proves nothing about the other, and the studies cited above all describe Selank itself.
Where to buy Selank for laboratory research
Molequa® supplies Selank as reference material for laboratory research in a 10 mg vial at 35.90 €, which is 3.59 € per mg. The batch certificate can be opened on the product page before ordering, and the material ships from a warehouse in the EU without customs clearance.
Product data and current availability are on the page for Selank research peptide, and the certificate is also published as a text and table version. Related molecules are in the cognitive peptides category.
Frequently asked questions
What is Selank in one sentence? A synthetic heptapeptide, Thr-Lys-Pro-Arg-Pro-Gly-Pro, derived from the immune peptide tuftsin and stabilised by an appended Pro-Gly-Pro sequence.
Is Selank an approved medicine in the EU or the US? No. Neither the EMA nor the FDA has approved it, and its Russian registration carries no regulatory weight in the EU. Molequa® sells Selank exclusively as reference material for laboratory research.
How many studies on Selank exist? A PubMed search restricted to title and abstract returned 68 records on 8 October 2026, 39 in English. Three are indexed as clinical trials, all Russian-language.
What is the difference between Selank and N-acetyl Selank? They are two different molecules. N-acetyl Selank carries an acetylated N-terminus, so its mass differs from the 751.9 Da of Selank, and a certificate for one does not confirm the other.
How do I verify Selank before buying? Check that the certificate names the batch on your vial, the analysis date and the laboratory, shows HPLC purity with a chromatogram and confirms identity by mass spectrometry at 751.9 Da.
Legal note
Selank is intended exclusively for laboratory research (Research Use Only). It is not a medicinal product, dietary supplement or cosmetic and is not intended for use in humans or animals. This article summarises published literature and makes no health claim.
