Cognition Peptides — Semax, Selank, Cerebrolysin
Made in the USSR
Semax and Selank are synthetic peptide analogues of ACTH(4-10) and tuftsin, developed in the Soviet Union in the 1990s. Cerebrolysin is a porcine brain-derived peptide mix used in European clinical neurology for decades. All three are used clinically outside the US, none are FDA-approved.
Cerebrolysin has the deepest human data
Used in stroke recovery and dementia in ~50 countries. Multiple RCTs, with modest but replicable cognitive benefits in post-stroke and vascular dementia populations. Cochrane reviews describe the effect as small and the evidence quality as moderate.
Semax + Selank: real mechanisms, thin evidence
Semax upregulates BDNF (the brain's growth factor); Selank modulates GABA. Both have Russian-language clinical evidence for ADHD, anxiety, and stroke recovery that hasn't been replicated in Western trials. The claims are biologically plausible but under-tested by global standards.
Why neurotrophic peptides matter
BDNF (brain-derived neurotrophic factor) is one of the strongest correlates of cognitive resilience, mood, and long-term dementia protection. Anything that raises BDNF safely is interesting. Exercise raises it. Cold exposure raises it. Cognitive peptides claim to, with varying levels of evidence.
Free cognitive levers vs paid peptides
Before chasing peptide nootropics, the evidence-backed levers for BDNF + cognitive function — most of them free — are: 30–40 minutes of moderate-to-vigorous exercise (acute BDNF rises 25–80 %); 7+ hours of sleep (sleep deprivation tanks BDNF + memory consolidation); 2 hours/week of social interaction (Bryden + Allen 2014 cohort showed 50 % lower dementia risk); bilingual practice or learning an instrument (cognitive-reserve effect); Mediterranean diet (MIND diet trial). Stack those before reaching for compounded peptides — the effect sizes are larger and the evidence base is far stronger.
Key Takeaway
Cerebrolysin has a real clinical niche (stroke recovery, vascular dementia) with moderate evidence. Semax and Selank are biologically plausible but under-studied outside Russia. None is FDA-approved — and the quality of material people actually buy is variable. The free cognitive levers (exercise, sleep, social, learning) outperform any peptide and should come first.