Side-by-side · Research reference
LL-37vsSemax
Side-by-side comparison across mechanism, dosage, evidence, side effects, administration, and stack synergies. Citations on every claim where available.
AHuman-MechanisticHUMAN-REVIEWED15/35 cited
BHuman-MechanisticAUTO-DRAFTED12/39 cited
LL-37
Cathelicidin · Human AMP
Broad-spectrumAntimicrobial activity
Endogenous · Secreted at inflammation sites
Semax
Cognitive enhancer · Russian Pharma
Intranasal · 2–3×/day during cognitive demand
01Mechanism of Action
Parameter
LL-37
Semax
Primary target
BDNF / NGF expression + monoamine modulationKaplan 2017
Pathway
hCAP-18 precursor → Proteinase-3 cleavage → LL-37 release → Membrane insertion/disruption
↑ BDNF + NGF synthesis + 5-HT modulation → neuroplasticity + anxiolysis + cognitive enhancementKaplan 2017
Downstream effect
Membrane permeabilization, cytokine induction, autophagy, phagosome-lysosome fusion, chemotaxisAhmad 2026Zhang 2026
Improved memory + attention; reduced anxiety; neuroprotection in ischemiaKaplan 2017
Feedback intact?
—
—
Origin
Endogenous human cathelicidin (37-AA fragment, residues 134–170 of hCAP-18)
Synthetic 7-AA peptide derived from ACTH(4-7) with C-terminal Pro-Gly-Pro stabilising tailKaplan 2017
Antibody development
—
—
02Dosage Protocols
Parameter
LL-37
Semax
Endogenous expression
Constitutive in neutrophils, epithelial tissues
Upregulated during infection and inflammation.Pinheiro 2026
—
Exogenous (experimental)
Dose varies by study; antimalarial ~10–50 μM in vitro
No FDA-approved exogenous formulation.
—
Plasma levels (malaria)
Elevated in infected patients and miceHe 2026
Exogenous administration reduced parasitemia in murine models.He 2026
—
Evidence basis
In vitro, animal models, human observational
Human-mechanistic + Russian clinicalKaplan 2017
Frequency
—
2–3× per day during cognitive demand
Lower / starter dose
—
100 mcg / dose
Duration
—
10–14 day cycles, repeated PRN
Reconstitution
—
Pre-formulated nasal spray (commercial); research vial: bacteriostatic water
Timing
—
Morning + early afternoon
Half-life
—
Short plasma; CNS effect lasts ~3–6 hr
04Side Effects & Safety
Parameter
LL-37
Semax
Cytotoxicity (high dose)
Membrane disruption in host cells at supraphysiological concentrations
—
Pro-inflammatory signaling
Can exacerbate inflammation in certain contexts (context-dependent)Pinheiro 2026
—
Theoretical cancer risk
Immunomodulatory roles in tumor microenvironment under investigation
—
Nasal irritation
—
Mild burning or congestion (transient)
Sleep disruption
—
Late-day dosing may interfere with sleep
Headache
—
Uncommon, transient
Long-term safety
—
Limited Western RCT data
Pregnancy / OB
—
Avoid
Absolute Contraindications
LL-37
—Semax
- ·Pregnancy / breastfeeding
Relative Contraindications
LL-37
- ·Active autoimmune disease (theoretical immune dysregulation)
Semax
- ·Active psychiatric instability
- ·Concurrent strong stimulants
05Administration Protocol
Parameter
LL-37
Semax
1. Natural secretion
LL-37 is constitutively expressed in neutrophils and epithelial cells, cleaved from hCAP-18 by proteinase-3 at sites of infection or inflammation.
Pre-formulated nasal spray (commercial) or research vial reconstituted with bacteriostatic water.
2. Experimental formulations
Synthetic LL-37 and derivatives (e.g., SAMP-12aa) tested in vitro and animal models. Administered via topical, intraperitoneal, or intravenous routes in research settings.
Intranasal — 2–3 sprays per nostril per dose. Tilt head slightly back.
3. Stability considerations
LL-37 is resistant to pepsin degradation at gastric pH. Synthetic short peptides designed to retain this stability while reducing toxicity.Lu 2026
Morning + early afternoon. Avoid evening (sleep disruption).
4. Storage
—
Refrigerate after reconstitution; light-protected.
5. Caveat
—
Cycle on/off to avoid neurochemical adaptation.
06Stack Synergy
LL-37
— no documented stacks
Semax
+ Selank
ModerateSemax (cognitive enhancer, BDNF/NGF) and Selank (anxiolytic + immune) form the canonical Russian "neuro stack" — both intranasal peptide bioregulators with complementary axes. Semax for cognitive demand; Selank for stress mitigation.
- Semax
- 200–600 mcg intranasal · morning + afternoon
- Selank
- 150–300 mcg intranasal · midday + early evening
- Primary benefit
- Cognitive enhancement + stress mitigation