Semax vs Selank: The Two Russian Peptides Side by Side
Semax and Selank are different peptides from different source proteins, sold as a stack. Structure and evidence compared side by side, with no winner declared.
The short version
Semax and Selank are two different peptides from Russian research programmes, often sold and taken together as a stack. They are different molecules from different parent proteins. Both rest on a narrow, unreplicated body of mostly Russian-language work, so neither has the stronger case.
- Semax derives from ACTH; Selank derives from tuftsin. Different parent proteins, different structures.
- Both rest on a literature that is mostly Russian-language and has not been independently replicated.
- Neither is approved for human use outside Russia, and both are sold as research chemicals.
Semax and Selank get sold as a matched pair, often in the same listing, sometimes in the same vial. They are not one compound. This page puts them side by side without merging them.
For the fuller account of the literature behind both, including how I counted it, see Semax and Selank.
Side by side
| Semax | Selank | |
|---|---|---|
| Parent structure | Fragment of ACTH (adrenocorticotropic hormone) | Fragment of tuftsin |
| Compound class | ACTH-derived peptide | Tuftsin-derived heptapeptide |
| Developed for | Russian neurology | Russian anxiolytic research |
| Marketed elsewhere as | Nootropic for focus, memory and mood | Nootropic for focus, memory and mood |
| PubMed records | 231 total, 105 Russian-language | 135 total, 33 Russian-language |
| Tagged clinical trials | 4 | 6 |
| Tagged randomised trials | 1 (Russian-language, 2007, chronic partial denervation) | 3 tagged, one a likely false-positive match, leaving 2 Russian-language papers (2008, 2015) |
| Evidence level | Limited | Limited |
| US legal status | Research-only | Research-only |
Full records for each: Semax and Selank, or both together in Semax and Selank.
What each is
Semax comes from a fragment of ACTH and is used in Russian neurology. Selank comes from tuftsin and was developed in Russia as an anxiolytic. Both are short synthetic peptides from the same national research tradition. Neither is a variant of the other.
Some listings frame this as a choice between the two for anxiety. The record doesn’t support that. Selank’s tagged trials are anxiety and neurasthenia studies 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 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. Semax’s one tagged randomised trial is a motor neuron disease study, not an anxiety study 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. Comparing the two “for anxiety” sets a studied indication against one that has not been studied at all.
What the literature looks like for each
The two literatures have nearly the same shape at different scale.
- Semax: 231 PubMed records, 105 of them Russian-language. Four are tagged as clinical trials and one as randomised. That one is Russian-language, from 2007, and concerns chronic partial denervation rather than the marketed cognitive use 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.
- Selank: 135 records, 33 Russian-language, six tagged as clinical trials. Of three tagged randomised, one is a muscular strength and hypertrophy paper that appears to be a false positive of the search, not a Selank trial. 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.
Neither trial record has been independently replicated in the literature most readers can access. Both are old, with the tagged randomised papers dating from 2007 to 2015. Modern English-language work on the ACTH-derived family 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. That is relevant background, not an efficacy result for either compound.
Stacking
Vendors sell Semax and Selank as a matched pair. That is a marketing pattern, not a clinical protocol. No trial in either literature tests the two together, and this page does not describe a combined dose.
Who should not use either compound
Neither compound has the safety record to support a blanket recommendation for anyone. Both are sold as research chemicals, not medicines, with no approved dose, no approved duration of use and no regulator-reviewed safety profile. The evidence level for both is already rated Limited across the general population. The record behind this page has no separate safety data for pregnancy, breastfeeding, or use alongside prescription medication.
Duration of use is decided by sellers, not shown by a trial. No paper behind this page reports how long either compound was used or what a safe length of use would be, so this page does not state one.
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. Both are used clinically in Russia and sold elsewhere through research-chemical channels, where nobody verifies the contents of the vial.
Related
Common questions
Is Semax the same as Selank?
No. Semax comes from a fragment of ACTH. Selank comes from tuftsin. They are different peptides from different source proteins, studied in the same Russian research tradition and often sold together as a stack.
Which has better evidence, Semax or Selank?
Neither. Semax has 231 PubMed records, 105 of them Russian-language. Selank has 135, 33 of them Russian-language. Both sit at the same evidence level for the same reason: the literature is unreplicated and comes largely from one research tradition.
Can you take Semax and Selank together?
This page describes what each compound is and what the evidence says. It is not a protocol. Neither compound has the human evidence to support a recommended combination.
Is Semax good for ADHD?
This page has no ADHD evidence for Semax. Its one tagged randomised trial covers chronic partial denervation in motor neuron disease, not attention or focus. No trial counted for this page studied Semax for ADHD.
Who should not take Semax?
Semax as sold in the US has no approved dose, no approved duration of use and no regulator-reviewed safety profile. That means there is no official list of who should avoid it. The record behind this page has no separate safety data for pregnancy, breastfeeding or use alongside prescription medication. Nobody verifies what is in the vial.
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.
- 1.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.Randomised trialPMID 18454096
- 2.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.Randomised trialPMID 26356395
- 3.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.Randomised trialPMID 18379501
- 4.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).StudyPMID 37510287full text