Comparison
The two Russian-developed intranasal peptides that dominate nootropic discussion.
Semax is positioned for cognition and focus, selank for anxiety; both rest mainly on Russian domestic literature, with semax having the deeper research history.
Semax is an ACTH(4-7)-analog fragment developed for stroke and cognitive applications, discussed for focus and mental stamina. Selank is a tuftsin-derived analog developed as an anxiolytic, discussed for anxiety and stress resilience. Community schedules overlap: roughly 300 to 600 mcg intranasal for semax and 250 to 500 mcg for selank, one to three times daily.
Semax has the larger research footprint, including Russian stroke literature and registration as a medicine in Russia; selank's human data are smaller domestic anxiety studies. Neither has been evaluated in Western-controlled trials, and semax appears on FDA's 2026 compounding advisory agenda.
N-acetyl semax amidate and N-acetyl selank amidate are vendor modifications with no published literature. Anything claimed for them is extrapolated from the parent molecules, and product identity is vendor-defined.
| Dimension | Semax | Selank |
|---|---|---|
| Overall evidence grade | D | D |
| Evidence label | Limited human evidence | Limited human evidence |
| Regulatory status | Varies by product and jurisdiction | Not FDA-approved for listed uses |
| Editorial confidence | Low confidence | Low confidence |
| Efficacy | 2/5 limited | 0/5 not mapped |
| Safety | 2/5 limited | 0/5 not mapped |
| Regulatory risk | 4/5 high | 3/5 moderate |
| Product quality risk | 4/5 high | 3/5 moderate |
| Primary claim categories | Cognitive claims, Neurologic research, Nasal peptide claims, Route-comparison claims | Neuro and cognition |
Semax can be described as a CNS-oriented peptide with limited route-specific human evidence, but subcutaneous superiority remains a clinic and forum claim rather than a demonstrated human route advantage.
Limited Russian clinical literature; elsewhere unproven.
PubMed. Effectiveness of Semax in acute period of hemispheric ischemic stroke 1997.
PMID:11517472 Accessed 2026-06-08.
Russian-language controlled clinical trial in acute hemispheric ischemic stroke; route and regimen context require direct-source verification before any protocol display.
PubMed. Kinetics of Semax penetration into the brain and blood of rats after intranasal administration 2006.
doi:10.1134/s1068162006010055 PMID:16523722 Accessed 2026-06-08.
Rat tracer study supporting intranasal brain/blood exposure plausibility; not direct human efficacy evidence.
PubMed. The efficacy of Semax in the treatment of patients at different stages of ischemic stroke 2018.
doi:10.17116/jnevro20181183261-68 PMID:29798983 Accessed 2026-06-08.
Human stroke rehabilitation study reporting BDNF, motor-performance, and Barthel-index outcomes; keep regimen details study-reported only.
FDA. July 23-24, 2026: Meeting of the Pharmacy Compounding Advisory Committee 2026.
Accessed 2026-07-24.
FDA meeting page for the July 23-24, 2026 PCAC review of BPC-157, KPV, TB-500, MOTs-C, emideltide/DSIP, Semax, and Epitalon bulk substances, including the uses evaluated for each, briefing documents, and docket FDA-2025-N-6895.