LL-37
Dosage Protocol
LL-37 is the only human cathelicidin antimicrobial peptide, derived from the C-terminus of the CAP-18 protein. It demonstrates broad-spectrum bactericidal activity, disrupts biofilms, modulates immune cell function, and promotes wound healing and angiogenesis. It is expressed in neutrophils, epithelial cells, and keratinocytes — serving as a key component of innate immune defense.
What is LL-37?
LL-37 is a 37-amino acid cationic peptide with the N-terminal Leu-Leu residues that give it its name. It is generated by protease cleavage of the 18 kDa CAP-18 protein. Its amphipathic helical structure enables it to insert into and disrupt bacterial membranes through a carpet or toroidal pore mechanism, producing broad-spectrum bactericidal activity including against multidrug-resistant organisms.
Beyond direct antimicrobial activity, LL-37 modulates innate immunity — it promotes dendritic cell maturation, activates TLR signaling, stimulates angiogenesis via FPRL1 and EGFR receptors, and promotes keratinocyte migration for wound healing. Research interest focuses on its applications in chronic wound healing, drug-resistant infections, and immune modulation.
Dosing Schedule
Parameters documented in published preclinical and clinical research.
| Phase | Dose | Frequency | Duration | Notes |
|---|---|---|---|---|
| Systemic | 50–100 mcg | Daily SubQ | 5–14 days | Subcutaneous administration for systemic infection or immune support research. |
| Wound healing | 100–200 mcg/mL | Topical application | Per wound | Applied directly to wound bed in saline solution 1–2× daily. |
| Working dose | 100 mcg | Daily or every other day | 2–4 weeks | Standard SubQ research dose for immune and wound healing studies. |
| High-dose | 200 mcg | Daily SubQ | 1–2 weeks | For acute protocols — monitor local injection site tolerance. |
Safety & Side Effects
Academic References
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[1]
Zanetti M. (2004). Cathelicidins, multifunctional peptides of the innate immunity. J Leukoc Biol. 75(1):39–48. PubMed ↗
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[2]
Agerberth B, et al. (1999). The human antimicrobial and chemotactic peptides LL-37 and alpha-defensins are expressed by specific lymphocyte and monocyte populations. Blood. 96(9):3086–93. PubMed ↗
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[3]
Heilborn JD, et al. (2003). The cathelicidin anti-microbial peptide LL-37 is involved in re-epithelialization of human skin wounds. J Invest Dermatol. 120(3):379–89. PubMed ↗
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[4]
Vandamme D, et al. (2012). A comprehensive summary of LL-37, the factotum human cathelicidin peptide. Cell Immunol. 280(1):22–35. PubMed ↗