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88/100May 2026 review (v3.0 rubric); v4.1 re-score pending
Offering and price for this peptide not verified in the October 15, 2026 update.
Read review →Recovery · Antimicrobial Peptide
LL-37 (Cathelicidin)
Released: Last reviewed:
LL-37 is a 37-amino-acid antimicrobial peptide derived from the human cathelicidin protein. Studied for chronic Lyme, biofilm-associated infections, wound healing, and immune modulation.
LL-37 (Cathelicidin) at a glance
LL-37 is a 37-amino-acid antimicrobial peptide derived from the human cathelicidin protein. Studied for chronic Lyme, biofilm-associated infections, wound healing, and immune modulation. Mechanism: Cathelicidin antimicrobial peptide. Typical route: Subcutaneous. FDA status: Not FDA-approved. Dispensed primarily by peptide compounding pharmacies for off-label use in chronic infection, autoimmune, and recovery protocols.
Drug classCathelicidin antimicrobial peptide
Half-life~24 hours
RouteSubcutaneous
Common dosing100-500 mcg/day
FDA statusNot approved
Available throughSee the dated FDA status notice above
Mechanism of action
LL-37 disrupts bacterial cell membranes, neutralizes lipopolysaccharide, and modulates the human immune response by activating macrophages and supporting tissue repair. It has direct antimicrobial activity against gram-positive and gram-negative bacteria, fungi, and some viruses.
Dosing reference
Subcutaneous: 100-500 mcg once daily, often cycled 5 days on / 2 days off for 4-8 weeks. Higher doses are used in some clinical protocols for chronic infectious conditions.
Dosing information is provided for educational reference and is not medical advice. Patients should not initiate or modify any peptide regimen without consulting a licensed clinician. See our medical disclaimer.
FDA status & regulatory framework
Not FDA-approved. Dispensed primarily by peptide compounding pharmacies for off-label use in chronic infection, autoimmune, and recovery protocols.
U.S. telehealth providers that work with LL-37 (Cathelicidin)
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70/100May 2026 review (v3.0 rubric); v4.1 re-score pending
Offering and price for this peptide not verified in the October 15, 2026 update.
Read review →–
85/100May 2026 review (v3.0 rubric); v4.1 re-score pending
Offering and price for this peptide not verified in the October 15, 2026 update.
Read review →–
71/100May 2026 review (v3.0 rubric); v4.1 re-score pending
Offering and price for this peptide not verified in the October 15, 2026 update.
Read review →Related recovery peptides
Frequently asked questions about LL-37 (Cathelicidin)
What is LL-37 used for?
LL-37 is most often used by patients with chronic Lyme disease, biofilm-related infections, or persistent inflammation. The peptide is also studied for skin-condition recovery and immune support.
Are there side effects?
Common reported side effects include flu-like symptoms, injection-site reactions, and short-term fatigue. Patients with autoimmune conditions should consult their physician given the peptide's immunomodulatory effects.
References
- A comprehensive summary of LL-37, the factotum human cathelicidin peptide. Cell Immunol. 2012;280(1):22-35. PMID: 23246832
- LL-37, the only human member of the cathelicidin family of antimicrobial peptides. Biochim Biophys Acta. 2006;1758(9):1408-1425. PMID: 16716248
Sources are peer-reviewed where available. PubMed (PMID) links resolve to NCBI's PubMed database. FDA links resolve to the U.S. Food and Drug Administration. Citations were last verified 2026-05-11.