Last updated: May 18, 2026
Top cognitive peptides
1. Semax
Synthetic ACTH (4-10) analog. Heptapeptide. Strong evidence for BDNF upregulation, cognitive enhancement in healthy adults, and neuroprotection. Intranasal route bypasses BBB. Russian-approved for ischemic stroke and cognitive disorders.
2. Selank
Synthetic tuftsin analog. Heptapeptide. Anxiolytic effects without GABA receptor activation. Cognitive effects via serotonergic and noradrenergic modulation. Russian-approved for anxiety; off-label for cognitive use.
3. Cerebrolysin
Mixture of low-molecular-weight peptides derived from porcine brain proteins. Studied extensively for stroke, traumatic brain injury, Alzheimer’s, and vascular dementia. Approved in 40+ countries (not US FDA).
4. Dihexa (PNB-0408)
Synthetic angiotensin IV derivative. Potent synaptogenic effects in animal models. Phase 1 trials initiated for Alzheimer’s. Not approved for any indication.
5. FGL (FGL Peptide, ENA-actigen)
NCAM-derived 15-amino-acid peptide. Mimics neural cell adhesion molecule signaling. Studied for synaptic plasticity and cognitive enhancement.
6. Noopept (technically not a peptide, but related)
Synthetic dipeptide analog of piracetam. Cognitive enhancer with anxiolytic and neuroprotective effects. Available in Russia and online; not FDA-approved.
Mechanisms compared
| Peptide | Primary mechanism | Route |
|---|---|---|
| Semax | BDNF upregulation, neurotrophin signaling | Intranasal |
| Selank | GABA/serotonin/noradrenergic modulation | Intranasal |
| Cerebrolysin | Multi-peptide neurotrophic mimetic | IM/IV |
| Dihexa | Synaptogenic (HGF/c-Met pathway) | Oral/sublingual (under investigation) |
| FGL | NCAM mimetic, synaptic plasticity | Intranasal |
Research dosing
- Semax (0.1%): 1-2 drops each nostril, 2-3x daily for 7-14 days
- Selank (0.15%): 1-2 drops each nostril, 2-3x daily for 7-14 days
- Cerebrolysin: 5-30 mL IM or IV (clinical use; physician supervised)
- Dihexa: Research only; no standardized human dose
Russian research context
Most cognitive peptide research originates from Russian institutions (Institute of Molecular Genetics, Russian Academy of Sciences). The research base is substantial but uses different methodological standards than Western pharmaceutical trials. Russian-language research is often inaccessible to Western readers without specialist translation.
Safety profile
Generally well-tolerated peptides in this class. Intranasal routes minimize systemic exposure. Most common side effects:
- Nasal irritation (intranasal route)
- Mild headache
- Occasional fatigue or transient mood changes
Evidence quality ranking
- Cerebrolysin: Most Western RCT data, approved in 40+ countries
- Semax, Selank: Substantial Russian clinical research, growing Western interest
- Dihexa: Strong preclinical, Phase 1 trials initiated
- FGL, others: Limited but promising
Which cognitive peptide works fastest?<br />
Semax produces noticeable cognitive effects within 30-60 minutes of intranasal dosing. Selank’s anxiolytic effects appear within similar timeframe.
Can these be combined with conventional nootropics?<br />
Often used alongside racetams (piracetam, aniracetam) and choline precursors. Mechanism compatibility is generally favorable.
Are intranasal peptides better than injectable?<br />
For brain-targeting peptides like Semax and Selank, intranasal allows direct olfactory pathway access to CNS — bypassing the blood-brain barrier. For Cerebrolysin, injection is needed due to molecular size.
Is Cerebrolysin available in the US?<br />
Not FDA-approved. Some compounding pharmacies and telehealth services offer it. Imported from countries where it’s approved.