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The dad-test answer
These are sister peptides developed by the same Russian institute. Selank is the 'calm' peptide - GABA-modulating, anxiolytic, compared head-to-head to a benzodiazepine in one Russian trial. Semax is the 'focus' peptide - BDNF-upregulating, used as a nasal spray for cognitive support and stroke. Selank for anxiety, Semax for focus and brain insult recovery. Most operators run them on different days for different goals.
Who wins for what
| Use case | Who wins, and why |
|---|---|
| generalized anxiety, situational stress |
selank Zozulya et al. 2008 compared Selank to medazepam (a benzodiazepine) in GAD patients - similar anxiolytic effect without sedation or dependence. |
| focus, cognitive performance, working memory |
semax Russian-approved for cognitive support; BDNF upregulation in animal models supports the focus and learning case. |
| post-stroke recovery, brain insult |
semax Russian Ministry of Health approval includes ischemic stroke recovery; Selank has no equivalent indication. |
| side-effect profile, dependence risk |
tie Both have clean Russian safety records and no reported dependence pattern; far cleaner than benzodiazepine alternatives for anxiety. |
What the head-to-head data shows
Both Selank and Semax were developed by the Institute of Molecular Genetics in Russia; both are approved as 0.1% intranasal sprays by the Russian Ministry of Health and remain unapproved by the FDA. Selank is a synthetic tetrapeptide based on the immunomodulator tuftsin; the key clinical paper is Zozulya et al. 2008 - 62 patients with generalized anxiety disorder and neurasthenia, randomized to Selank vs medazepam (a benzodiazepine), with similar anxiolytic effects measured on Hamilton and Zung scales but Selank also producing antiasthenic and mild psychostimulant effects without the sedation. Medvedev et al. 2015 covers Selank optimization in anxiety treatment. Semax is an N-terminal ACTH (4-7) analog; Kaplan et al. 1996 characterizes the neurotrophic and anxiolytic effects via BDNF and NGF upregulation. Most of the literature on both peptides is in Russian-language journals and small cohorts - the English-language peer-reviewed record is thin compared to FDA-approved alternatives.
Our honest call
The two peptides are genuinely complementary, not interchangeable. For anxiety - especially situational stress, public speaking, exam stress, or generalized anxiety where a benzodiazepine is overkill - Selank is the cleaner option and the Zozulya benzo head-to-head is the closest thing to real comparative evidence. For focus, learning, and brain insult recovery, Semax has the regulatory record and the BDNF mechanism. Most operators we trust run them on different days for different goals - Selank when stress is the limiter, Semax when focus or recovery is. We have not personally validated either peptide. The honest framing: the English-language evidence base is thin, the Russian record is real but harder to verify, and the gray-market US sourcing requires standard COA and 503B-licensed pharmacy diligence.
Sources and citations
- Zozulya et al., Selank vs medazepam in GAD and neurasthenia, Zh Nevrol Psikhiatr 2008 (PMID 18454096)
- Medvedev et al., Selank optimization in anxiety treatment, 2015 (PMID 26356395)
- Kaplan et al., Semax neurotropic effects, Neurosci Behav Physiol 1996 (PMID 9148939)
- Russian Ministry of Health Selank registration (2009)
- Russian Ministry of Health Semax registration (1995)
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Last reviewed · 2026-05-07 · Page generated by Protocol One matrix engine. None of this replaces a doctor. Peptides are gray-market in the US for most uses. Talk to a real prescriber before you change anything.