Research peptides

Semax and Selank: Where That Russian Research Actually Sits

Both rest on a real but narrow literature: mostly Russian-language, mostly two decades old, never independently replicated. I counted it rather than repeating it.

Written bySebastian Hunter, Founder and EditorI'm a 42-year-old senior advisor and distance runner who came to peptides as a sceptic. I'm not a doctor: I read the research, run my own experiment and keep honest notes. Read full bio

Published August 23, 2026

The short version

Semax and Selank are peptides developed in Russia and used there clinically, sold elsewhere as nootropics. Their human evidence is real but narrow: mostly Russian-language journals, mostly two decades old, and not replicated in the wider literature. That is a specific limitation, not a dismissal.

Of 231 Semax records on PubMed, 105 are Russian-language. For Selank it is 33 of 135.
The controlled trials are old and have not been independently replicated.
Neither is approved for human use outside that tradition, and both sell as research chemicals.

Each compound now has its own full page: Semax and Selank. This page stays live for the shared comparison and because it has inbound links.

Dosing: what the Semax studies used and what the Selank studies (don’t) establish. Regulatory changes for these compounds and others, as they happen: US peptide regulation tracker.

Almost everyone who writes about Semax and Selank says the same thing: “the research is mostly older Russian studies.” It is repeated as either a dismissal or a wink, depending on who is selling what, and almost nobody checks it. I checked. It is true, and the specifics are more useful than the sentence.

What they are

Both are short synthetic peptides developed in Russia and used clinically there. Semax derives from a fragment of ACTH and is used in neurology. Selank derives from tuftsin and was developed as an anxiolytic. Elsewhere they are sold as research chemicals and marketed as nootropics.

What the literature actually looks like

Semax on PubMed, by language of publication

Russian-language recordsof 231 total
105
Tagged as a clinical trialacross the whole corpus
4
Tagged as a randomised trialRussian-language, 2007
1

Counted on PubMed in August 2026. Almost half the Semax literature is Russian-language, and the concentration is heavier still among the clinical studies rather than the laboratory work.

Selank has the same shape at a smaller scale: 135 records, 33 of them Russian-language, 6 tagged as clinical trials and 3 as randomised.

Those 3 randomised records do not hold up on inspection:

One is a muscular strength and hypertrophy paper that looks like a false positive of the search, not a Selank trial at all.
The other two are Russian-language papers in the Korsakov journal of neurology and psychiatry, from 2015 Medvedev 2015 - Medvedev VE, Tereshchenko ON, Kost NV et al. [Optimization of the treatment of anxiety disorders with selank]. Zh Nevrol Psikhiatr Im S S Korsakova. 2015;115(6):33-40., in the references below and 2008 Zozulia 2008 - Zozulia AA, Neznamov GG, Siuniakov TS et al. [Efficacy and possible mechanisms of action of a new peptide anxiolytic selank in the therapy of generalized anxiety disorders and neurasthenia]. Zh Nevrol Psikhiatr Im S S Korsakova. 2008;108(4):38-48., in the references below.

Semax’s single randomised record is in the same journal, from 2007, and concerns chronic partial denervation Serdiuk 2007 - Serdiuk AV, Levitskiĭ GN, Miasoedov NF et al. [The study of chronic partial denervation and quality of life in patients with motor neuron disease treated with semax]. Zh Nevrol Psikhiatr Im S S Korsakova. 2007;107(4):29-39., in the references below.

What that means

The studies are not worthless. Non-English research is research, and waving away a national research tradition because it published in its own language is a bias of its own. These compounds were developed in a serious programme and used in clinical practice.

What it does mean is three things:

The work has not been independently replicated in the literature most readers, clinicians and regulators can access and appraise.
The clinical trials are roughly two decades old.
You cannot easily check them yourself, and neither can I, so I do not summarise their results as though I had.

Modern English-language work on these peptides does exist, but it is mechanistic rather than clinical, for instance on how synthetic ACTH-derived peptides alter gene expression patterns Filippenkov 2023 - Filippenkov IB, Remizova JA, Stavchansky VV et al. Synthetic Adrenocorticotropic Peptides Modulate the Expression Pattern of Immune Genes in Rat Brain following the Early Post-Stroke Period. Genes (Basel). 2023;14(7)., in the references below. It is interesting, but it does not answer whether they help you concentrate.

Dose

I am not transcribing dosing out of papers I cannot fully read. I report doses where a study establishes one and I can verify what it did. Here the clinical work sits in journals that are difficult to obtain and appraise. Passing along numbers filtered through vendor translations would give them a provenance they do not have.

Status

US legal status - Research use only

Sold for laboratory research use only. Not approved by the FDA for human use, and cannot be lawfully marketed as a supplement or a medicine. Products sold this way are not made to pharmaceutical quality standards, and their contents are not verified by anyone.

Neither peptide is approved for human use in the US, and both are sold through research-chemical channels where nobody verifies the contents of the vial. You will see claims that they are “approved medicines”. That is true in Russia and not where you are buying them, and vendors rarely make the distinction.

Common questions

What are Semax and Selank?

Both are short synthetic peptides developed in Russia. Semax derives from a fragment of ACTH and is used there in neurology; Selank derives from tuftsin and was developed as an anxiolytic. Outside Russia they are sold as research chemicals and marketed as nootropics.

Is the research on Semax and Selank real?

Yes, but it is narrower than either promoters or critics suggest. There are real clinical studies in real journals from a genuine research programme. They are overwhelmingly Russian-language, largely from one tradition, mostly two decades old, and not independently replicated in the literature most readers can access.

Do Semax and Selank work for focus, memory or anxiety?

That is what they are studied and used for in their home tradition. What is missing is independent replication, so nobody outside that tradition can check the result. The evidence exists and is hard to verify; it is neither conclusive nor absent.

Are Semax and Selank legal?

They are not approved for human use in the US, and are sold through research-chemical channels where no regulator checks that a vial matches its label. In Russia they have been used clinically, which is why you will see claims that they are approved medicines. That is true there, not here.

What dose do the studies use?

The clinical work is largely in Russian-language journals that are difficult to obtain and appraise. I am not going to transcribe dosing out of papers I cannot fully read. So I give no dose for these two.

References (4 sources)

Bibliographic detail is fetched from PubMed, not written by me - so a citation here cannot drift from the paper it names. Study design comes from PubMed's own tags rather than my judgement.