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The Peptide Effect
Comparison

Selank vs Semax

Selank and Semax are both Russian-developed regulatory peptides with nootropic and neuroprotective properties, but they target different neurochemical pathways. Selank, a synthetic tuftsin analog, primarily modulates GABA and serotonin systems to produce anxiolytic and calming effects. Semax, an ACTH(4-10) fragment analog, upregulates BDNF and enhances dopaminergic and cholinergic signaling for cognitive stimulation and focus. Together they represent two complementary approaches to cognitive optimization — calm clarity vs. energized focus.

Side-by-side comparison diagram of Selank and Semax mechanisms of action
Conceptual comparison — not to scale

Head-to-Head Comparison

CriteriaSelankSemax
Primary mechanismTuftsin analog — GABAergic modulation, serotonin system regulationACTH(4-10) analog — BDNF upregulation, dopaminergic/cholinergic enhancement
Primary effect profileAnxiolytic, calming, stress reductionCognitive enhancement, focus, mental energy
Route of administrationIntranasal (nasal spray)Intranasal (nasal spray)
Typical dosage250–500 mcg, 2–3× daily intranasal200–600 mcg, 1–2× daily intranasal
Half-life~2–3 minutes (short, but effects last hours due to downstream signaling)~3–5 minutes (short, but BDNF effects persist for hours)
Effect on anxietyStrong anxiolytic — comparable to benzodiazepines without sedation or dependenceMild anxiolytic — secondary to cognitive effects; may increase alertness
Cognitive enhancementModerate — improves focus indirectly by reducing anxiety-related cognitive interferenceStrong — directly enhances memory consolidation, learning, and attention
NeuroprotectionModerate — anti-inflammatory and immunomodulatory neuroprotectionStrong — robust BDNF upregulation, neurogenesis, protection against ischemia
Immune modulationYes — derived from tuftsin, an immunomodulatory peptide; normalizes IL-6, TNF-αMinimal direct immune effects
Subjective feelCalm, centered, reduced mental chatter — "anxiolytic clarity"Alert, focused, mentally energized — "clean stimulation"
Regulatory statusApproved in Russia as anxiolytic; research chemical elsewhereApproved in Russia/Ukraine for stroke and cognitive disorders; research chemical elsewhere
Can they be stacked?Yes — commonly stacked with Semax for balanced cognitive enhancementYes — commonly stacked with Selank for focus + calm

When to Choose Each

Choose Selank

Anxiety reduction, stress resilience, social anxiety, calm focus, PTSD-related cognitive impairment, immune support

Choose Semax

Memory enhancement, learning, sustained focus, ADHD-like symptoms, stroke recovery, BDNF-dependent neuroprotection

Verdict

Choose Selank if anxiety, stress, or racing thoughts are your primary concern — it delivers benzodiazepine-level anxiolysis without sedation or dependence, making it ideal for social anxiety, generalized anxiety, or high-stress cognitive performance. Choose Semax if you need raw cognitive enhancement, better memory, and sustained focus — it is the stronger nootropic for studying, creative work, and productivity. Many users stack both for the best of both worlds: Semax for mental sharpness plus Selank for calm composure.

References

  1. Selank — a peptide analogue of tuftsin with nootropic and anxiolytic properties (2008) — PubMed
  2. Semax, an analogue of ACTH(4-10), regulates expression of immune response genes in human monocytes (2014) — PubMed
  3. Neuroprotective effects of Semax in conditions of cerebral ischemia (2006) — PubMed
  4. Anxiolytic effect of selank and its relation to changes in the content of monoamines (2008) — PubMed
  5. Effects of Semax on BDNF expression in the rat brain (2006) — PubMed

Frequently Asked Questions

Can I use Selank and Semax together?
Yes, stacking Selank and Semax is one of the most popular nootropic peptide protocols. They work through complementary mechanisms — Selank calms the nervous system via GABA/serotonin modulation while Semax stimulates cognition via BDNF and dopamine. A typical stack is Semax 300 mcg + Selank 300 mcg intranasal in the morning. The combination provides focused clarity without jitteriness.
Are Selank and Semax safe for long-term use?
Both peptides have been used clinically in Russia for decades with favorable safety profiles. Neither shows dependence, tolerance, or withdrawal effects in clinical data. However, long-term human studies outside Russia are limited. Most nootropic users cycle them (4–8 weeks on, 2–4 weeks off) as a precaution, though the pharmacological evidence does not strongly suggest this is necessary.
Do Selank and Semax work immediately or require loading?
Both peptides have acute effects noticeable within 15–30 minutes of intranasal administration. However, the full benefits — particularly BDNF upregulation from Semax and anxiolytic remodeling from Selank — build over 1–2 weeks of consistent use. Most users report peak benefits after 2–3 weeks of daily administration.
Why are Selank and Semax only available as nasal sprays?
Both peptides have extremely short plasma half-lives (2–5 minutes) and would be degraded by digestive enzymes if taken orally. Intranasal delivery bypasses the GI tract, allows partial direct nose-to-brain transport via the olfactory nerve, and provides rapid onset. Subcutaneous injection is also possible but intranasal is standard due to convenience and comparable bioavailability for these small peptides.
Are Selank and Semax legal to purchase outside of Russia?
Both peptides are approved prescription medications in Russia and some former Soviet states, but they are not approved by the FDA or EMA. In the United States and most Western countries, they are available as research chemicals and are not regulated as controlled substances. This means they can be purchased from research peptide suppliers, though they are sold "not for human consumption." Quality and purity can vary between vendors, so third-party testing certificates are important. Consulting a healthcare provider about their use and checking local regulations is recommended.

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