The verdict
Our read at a glance.
Whether LL-37 biology and narrow investigational wound signals can translate into defined therapies without turning endogenous host-defense mechanisms into broad infection, immune, or wellness claims.
- The signal
- The strongest human therapeutic signal is concentrated in chronic wound research. Outside those settings, most LL-37 references are biomarker, expression, immune-mechanism, antimicrobial assay, or translational safety-context sources rather than clinical outcome evidence.
- The unknown
- Whether any product-specific benefit survives tissue complexity, serum inhibition, proteolysis, inflammatory-disease biology, and identity differences between endogenous CAMP/hCAP18, native synthetic LL-37, investigational materials, analogs, compounded products, and internet-market products.
- Our read
- Real host-defense biology, narrow human wound signals, and enough double-edged immune and regulatory uncertainty to keep this firmly on watch.
The mechanism
How it works.
LL-37 is the active piece of cathelicidin, a host-defense protein the body makes as part of innate immunity. It punches holes in the membranes of bacteria to kill them directly, and it also signals to immune cells, drawing them to a site and influencing inflammation and wound repair. This double-edged role, antimicrobial but also inflammatory, is well established in the lab, while human therapeutic evidence is narrow and concentrated in chronic-wound research.
Safety & regulatory boundary
The consequential part.
FDA lists Cathelicidin LL-37 in its withdrawn-nominated bulk-substance safety-risk section and identifies potential significant safety risks for compounded drugs containing it. A current FDA PCAC page says Cathelicidin (LL-37) is planned for discussion before the end of February 2027; that is not an approval or final decision.
What's next
What we're watching.
Indication-specific clinical results, adverse-event characterization, FDA PCAC status, and whether future products clearly define identity, purity, endpoints, and population.
Context
Why this is discussed.
Antimicrobial, anti-biofilm, and immune narratives are appealing, especially when chronic wounds, infection risk, and antibiotic resistance are discussed.
The evidence base
65 cited references.
Regulatory & labels8
EU Clinical Trials Register · Results posted 2021
U.S. Food and Drug Administration · Current FDA page
U.S. Food and Drug Administration · Content current 2026-04-15
U.S. Food and Drug Administration · Content current 2026-04-15
U.S. Food and Drug Administration · Current FDA page
U.S. Food and Drug Administration · Updated 2026-05-14
Medsafe · June 2025
Medsafe · Published 2025-10-30
Registered trials2
ClinicalTrials.gov · NCT04098562
ClinicalTrials.gov · NCT02225366
Peer-reviewed journals3
Ramanathan et al. · 2018
Quraishi et al. · 2015
Kustrimovic et al. · 2017
Indexed literature (PubMed)47
Gronberg et al. · 2014
Mahlapuu et al. · 2021
Miranda et al. · 2023
Heilborn et al. · 2003
Tokumaru et al. · 2005
Sorensen et al. · 2003
Sluzewska et al. · 2016
Ballardini et al. · 2009
Bergsson et al. · 2009
Gordon et al. · 2005
Majewski et al. · 2018
Zhu et al. · 2019
Leaf et al. · 2015
Chromek et al. · 2006
Nishida et al. · 2018
Agerberth et al. · 1995
Sorensen et al. · 2001
Turner et al. · 1998
Scott et al. · 2002
Bowdish et al. · 2005
Vandamme et al. · 2012
Bandurska et al. · 2015
Pahar et al. · 2020
Overhage et al. · 2008
Memariani and Memariani · 2023
Sieprawska-Lupa et al. · 2004
Ciornei et al. · 2005
Oren et al. · 1999
Barlow et al. · 2010
Bankell et al. · 2021
Sochacki et al. · 2011
Liu et al. · 2006
Yamasaki et al. · 2006
Yamasaki et al. · 2007
Yoon et al. · 2021
Thibaut de Menonville et al. · 2017
Lande et al. · 2007
Ganguly et al. · 2009
Morizane et al. · 2012
Lande et al. · 2014
Herster et al. · 2020
Edfeldt et al. · 2006
Zhang et al. · 2015
Kahlenberg and Kaplan · 2013
Moreno-Angarita et al. · 2020
Piktel et al. · 2016
Sponsor & other sources5
NIH National Library of Medicine · Record modified 2026-01-24
NCBI Gene · Updated 2026-04-08
UniProt · Accession P49913
IUPHAR/BPS Guide to Immunopharmacology · Current database page
ChEMBL / EMBL-EBI · Current database page
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