Semax vs Selank: Russian Peptides and Thin Evidence
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[Peptides · Comparison]

Semax vs selank: how do they differ?

Structure · Human evidence · FDA status

Short answer: Both are Russian-developed seven-amino-acid peptides.1 Semax is built on an ACTH fragment and studied mainly for stroke;2 selank is a tuftsin analog studied for anxiety.3 Human data are thin: PubMed tags only 4 semax and 3 selank records as clinical trials, mostly in Russian-language journals.45 Neither is approved in the US.

How do semax and selank compare side by side?

From PubMed-indexed studies (several in Russian, read in English abstract), FDA pages and the 2026 WADA List.
SemaxSelank
What it isHeptapeptide Met-Glu-His-Phe-Pro-Gly-Pro: ACTH(4-7) plus Pro-Gly-Pro2Heptapeptide analog of tuftsin, an immune peptide13
Main studied useIschemic stroke recovery6Anxiety disorders7
Proposed mechanismRaised blood BDNF in a stroke study6GABA receptor modulation in lab studies1
PubMed records tagged as trials4 (October 2026)43 (October 2026)5
Example human study110 stroke patients; two 10-day courses of 6,000 mcg/day662 patients with anxiety or neurasthenia vs medazepam;7 60 patients vs phenazepam8
Half-lifeNo published human valueNo published human value
US statusNot approved. Nominated but withdrawn from FDA Category 29Not approved. Nominated but withdrawn from FDA Category 29
FDA advisory committee 2026Reviewed July 24, 2026 (cerebral ischemia, migraine, trigeminal neuralgia)10Not on the July 2026 agenda10

Reviewed . Half-life figures are shown only where the value Dose Track uses agrees with the cited source.

How are they built?

Both are seven amino acids long. Semax is Met-Glu-His-Phe, a piece of ACTH (the stress hormone that drives cortisol), followed by Pro-Gly-Pro.2 It is described as a nootropic rather than a hormone.11 Selank is built on tuftsin, a short immune-system peptide.3 Lab studies suggest selank acts on GABA receptors, the same system targeted by benzodiazepines.1

How much human evidence is there?

Very little that is easy to check. On October 22, 2026, PubMed tagged only 4 semax and 3 selank records as clinical or randomized trials,45 and most human studies are in Russian-language journals, so we could read only their English abstracts.

  • Semax: 110 people after ischemic stroke; those given semax had higher BDNF and better daily-function scores. The abstract does not describe randomization or blinding.6
  • Selank: in 62 patients its anti-anxiety effect was similar to medazepam;7 a 60-patient study compared it with phenazepam.8
  • Both: a brain-scan study in 52 healthy volunteers found short-term changes in amygdala connectivity after either peptide vs placebo.11

A 2021 US pharmacology review described selank as a "poorly studied" Russian drug sold to US consumers as a supplement.12 These are study protocols, not personalized advice; confirm any dosing with your prescriber.

What is their FDA status?

Neither is approved in the US. Both are on FDA's list of compounding substances that were in Category 2 and then withdrawn by their nominators; FDA says it lacks safety information for the proposed routes.9 FDA's advisory committee reviewed semax on July 24, 2026 for cerebral ischemia, migraine and trigeminal neuralgia; selank was not on the agenda.10

This page summarizes labels and published studies. It is not personalized medical advice; confirm any dose or change with your prescriber.
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Frequently asked questions

What is the difference between semax and selank?+
Semax is built on a fragment of ACTH and was studied mostly for stroke. Selank is built on tuftsin and was studied mostly for anxiety. 23
Is there good human evidence for semax or selank?+
Not much. PubMed tags only 4 semax and 3 selank records as trials, mostly small and published in Russian.45
Are semax and selank FDA approved?+
No. Both are on FDA's nominated-but-withdrawn compounding list, and FDA's advisory committee reviewed semax in July 2026.910
How does selank work?+
Lab studies suggest it modulates GABA receptors, the system benzodiazepines act on. This has not been confirmed in large human studies.1
Can I track semax and selank in Dose Track?+
Yes. Both are built in, so you can log nasal or injected doses with reminders.

Sources

  1. Vyunova TV, et al. Peptide-based anxiolytics: the molecular aspects of heptapeptide Selank biological activity. Protein Pept Lett. 2018;25:914-923.
  2. Magrì A, et al. Influence of the N-terminus acetylation of Semax, a synthetic analog of ACTH(4-10), on copper(II) and zinc(II) coordination. J Inorg Biochem. 2016;164:59-69.
  3. Kolik LG, et al. Selank, peptide analogue of tuftsin, protects against ethanol-induced memory impairment. Bull Exp Biol Med. 2019.
  4. PubMed search: semax[tiab] AND (randomized controlled trial[pt] OR clinical trial[pt]). 4 records on October 22, 2026.
  5. PubMed search: selank[tiab] AND (randomized controlled trial[pt] OR clinical trial[pt]). 3 records on October 22, 2026.
  6. Gusev EI, et al. The efficacy of semax in the treatment of patients at different stages of ischemic stroke. Zh Nevrol Psikhiatr Im S S Korsakova. 2018 (in Russian).
  7. Zozulia AA, et al. Efficacy and possible mechanisms of action of selank in generalized anxiety disorder and neurasthenia. Zh Nevrol Psikhiatr Im S S Korsakova. 2008;108:38-48 (in Russian).
  8. Medvedev VE, et al. A comparison of the anxiolytic effect and tolerability of selank and phenazepam in anxiety disorders. Zh Nevrol Psikhiatr Im S S Korsakova. 2014;114:17-22 (in Russian).
  9. FDA. Certain bulk drug substances for use in compounding that may present significant safety risks (Category 2 and nominated-but-withdrawn lists). Updated April 2026.
  10. FDA. Pharmacy Compounding Advisory Committee meeting, July 23-24, 2026.
  11. Panikratova YR, et al. Functional connectomic approach to studying Selank and Semax effects. Dokl Biol Sci. 2020;490:9-11.
  12. Doyno CR, White CM. Sedative-hypnotic agents that impact GABA receptors: focus on flunitrazepam, GHB, phenibut, and selank. J Clin Pharmacol. 2021.

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