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Inclusion of a compound does not constitute endorsement. Information sourced from published research and regulatory filings.

LL-37

Removed from Cat 2

Longevity & Immune · Research peptide (multiple suppliers)

Sole human cathelicidin antimicrobial peptide investigated for broad-spectrum antimicrobial activity, immune modulation, and wound healing. Not FDA-approved as a drug.


About

Mechanism
The only known human cathelicidin antimicrobial peptide. 37-amino-acid peptide naturally produced by neutrophils, epithelial cells, and other immune cells. Exhibits broad-spectrum antimicrobial activity by disrupting microbial membranes. Functions as an "alarmin," modulating immune responses, promoting wound healing, angiogenesis, and chemotaxis of immune cells.
Half-Life
Short — proteolytic instability limits in vivo half-life
Route
subcutaneous
Frequency
Once daily (community-derived, highly variable)

Clinical Dosing

100-500 mcgonce daily (community-derived, highly variable)

Not FDA-approved as a drug. Cited concerns include cytotoxicity at high concentrations, immunogenicity, and possible protumorigenic effects in certain contexts. Topical formulations appear better tolerated than systemic use in available data.

Dosing based on small human studies or early-phase trials. Not established by Phase 3 evidence. Topical formulations have stronger clinical evidence (wound healing) than systemic injection.


Regulatory Status

FDA Category
Previously placed in Category 2 (Sept 2023). Removed from Category 2 following April 15, 2026 announcement. Scheduled for PCAC review before end of February 2027.
Reclassification
removed-from-cat2
Date Restricted
2023-09-29
Announced Return
2026-02-27

Status based on publicly available FDA communications. Verify at FDA.gov for authoritative guidance.

View full regulatory timeline →

Titration Protocols

Research Reference Range

Source: Vandamme et al., Cellular Immunology, 2012 (review)

DoseDurationDraw (5 mg vial in 2mL)Notes
100 mcgMaintenance0.04 mL (4 units)Representative low-end community starting dose. Topical use is better characterized than systemic use.

Available Vial Sizes

5 mg

5 mg vial

10 mg

10 mg vial


Citations

  1. [1]A Comprehensive Summary of LL-37, the Factotum Human Cathelicidin Peptide. Cellular Immunology, 280(1), 22-35. Link(Reviewed: 2026-04-16)