Peptide Comparison
Semax vs Selank
Editorial breakdown of mechanism, evidence, decision criteria, and the misconceptions worth calling out.
Use together
Russian-approved nootropic peptides from the same research lineage. Semax (an ACTH 4-10 fragment) tilts dopaminergic, upregulates BDNF/NGF, and is daytime-focus oriented. Selank (a synthetic tuftsin analog) tilts GABAergic and is anxiolytic without sedation. They're paired in the Nootropic Duo stack precisely because the effects are orthogonal: focus plus calm. Both have decades of Russian clinical use; neither has a Western Phase 3 trial. Either accept the evidence ceiling or wait for replication.
Evidence at a glance
FDA-approved Phase 3 Phase 2 / approved abroad Anecdotal + animal Preclinical / flagged
The actual difference
Semax upregulates BDNF/NGF and modulates dopamine and serotonin, the classic 'growth factor plus dopamine focus' stack. Selank modulates GABA, serotonin, and enkephalin systems with immune-modulation overlap. Both intranasal, both fast-acting (peak in minutes), both metabolized rapidly.
Which one to pick
Pick Semax if
- Daytime focus, work or study performance
- Stroke recovery context (a Russia-approved indication for Semax)
- BDNF-target framing matters to you (some literature support)
Pick Selank if
- Anxiety reduction without sedation
- Stress-related physical symptoms
- Generalized anxiety where benzodiazepine tolerance and dependence are concerns
Avoid both if
- You need Western RCT-grade evidence before trying anything
- Severe persistent anxiety - see a clinician about validated treatments before research-grade peptides
- You're not prepared to vet vendor identity and purity (no regulated US supply)
Used together in
- Nootropic Duo: Focus + anxiolysis without sedation
- Cognitive + Sleep: Day focus / night recovery cycle
Common confusions
- 'Selank works like a benzodiazepine'. Partially. Both modulate GABA, but Selank's published mechanism doesn't appear to produce tolerance, dependence, or sedation in the Russian literature. Whether that holds up to Western Phase 3 scrutiny is genuinely unknown.
- 'These are FDA-approved overseas, so they're safe here'. Russian regulatory approval doesn't translate to FDA pathway. Buying them in the US is a research-chemical transaction with all the identity and purity caveats that implies.
- 'Semax and Adamax are the same'. Incorrect. Adamax is a different modified analog with different binding kinetics.
Side-by-side
| Semax | Selank | |
|---|---|---|
| Class | ACTH fragment analog; nootropic | Tuftsin analog peptide (anxiolytic/nootropic) |
| Drug class | Cognitive | Cognitive |
| Mechanism | Upregulates BDNF and NGF; modulates dopamine and serotonin systems; neuroprotective | Modulates GABAergic, serotonergic, and enkephalin systems; immune modulation |
| Route | Intranasal / SC | Intranasal / SC |
| Half-life | ~5-15 min (intranasal peak) | ~few min |
| Dosage (research) | 200 mcg intranasal daily (0.1% solution, 2-3 drops per nostril, nootropic starting dose, max 600 mcg/day per Russian clinical literature for stroke and cognitive support) | 250 mcg intranasal daily (0.15% solution, anxiolytic starting dose, range up to 500 mcg/day per r/Peptides wiki) |
| Evidence tier | Russia-Approved + Anecdotal | Russia-Approved + Anecdotal |
| Research depth | 180 indexed | 85 indexed |
| Availability | Research / Intl Rx | Research / Intl Rx |
| Reported risks | Mild irritability; insomnia; nasal irritation with intranasal use | Rare hypersensitivity; nasal irritation |
Reported research data only. "Studied for" and "reported in literature" describe published research focus, not clinical recommendation. Most peptides catalogued here are not FDA-approved for human use.
Frequently asked questions
Should I pick Semax or Selank?
Russian-approved nootropic peptides from the same research lineage. Semax (an ACTH 4-10 fragment) tilts dopaminergic, upregulates BDNF/NGF, and is daytime-focus oriented. Selank (a synthetic tuftsin analog) tilts GABAergic and is anxiolytic without sedation. They're paired in the Nootropic Duo stack precisely because the effects are orthogonal: focus plus calm. Both have decades of Russian clinical use; neither has a Western Phase 3 trial. Either accept the evidence ceiling or wait for replication.
What is the difference between Semax and Selank?
Semax is classed as ACTH fragment analog; nootropic; Selank is classed as Tuftsin analog peptide (anxiolytic/nootropic). Reported mechanism: Semax, Upregulates BDNF and NGF; modulates dopamine and serotonin systems; neuroprotective; Selank, Modulates GABAergic, serotonergic, and enkephalin systems; immune modulation. Reported half-life: Semax, ~5-15 min (intranasal peak); Selank, ~few min. Routes in published studies: Semax, Intranasal / SC; Selank, Intranasal / SC.
Which has stronger evidence, Semax or Selank?
Semax and Selank sit on the same rung of PeptideHelper.org's five-step evidence scale, which runs from preclinical to FDA-approved. Semax is graded Russia-Approved + Anecdotal, with 5 cited sources on its reference page and 180 indexed studies. Selank is graded Russia-Approved + Anecdotal, with 2 cited sources on its reference page and 85 indexed studies.
Which is more accessible, Semax or Selank?
Neither Semax nor Selank is an FDA-approved drug. Catalog status: Semax, Research / Intl Rx; Selank, Research / Intl Rx. Semax's nomination for FDA's bulk-substance lists was flagged by FDA and then withdrawn. Selank's nomination for FDA's bulk-substance lists was flagged by FDA and then withdrawn.
Are Semax and Selank ever combined?
Yes. Nootropic Duo, Cognitive + Sleep are documented stacks containing both Semax and Selank; the stack page gives the stated rationale.
Open the PeptideHelper.org compare tool to add more compounds to this side-by-side and filter by evidence tier interactively.
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