How do LL-37 and alpha-defensins differ?

LL-37 is the mature 37-residue peptide processed from hCAP18. Alpha-defensins comprise neutrophil HNP1–4 and intestinal HD5–6; HD6 can form pathogen-trapping nanonets rather than acting as a generic membrane-killing peptide.

Has either class shown human treatment benefit?

Native topical LL-37 has three published wound-trial populations with mixed outcomes. The selected HD5/HD6 studies characterize structure, mucosal defense or tissue expression, not administration as an established therapy.

Is LL-37 clinically stronger than alpha-defensins?

No direct therapeutic comparison was identified. Source totals and human tissue observations cannot rank efficacy or safety across a single peptide and a six-member family.

LL-37 vs Alpha-Defensins: Evidence and Limits (2026)

Dossier labels summarize each dossier's research scope. They do not establish comparative treatment benefit or safety. Read the comparison below in that context.

Biological identities

Mature LL-37 is processed from hCAP18 and is one human cathelicidin peptide. Human alpha-defensins are six related peptides: HNP1–4 occur mainly in neutrophils, whereas HD5 and HD6 are prominent in intestinal Paneth cells. Their disulfide-stabilized structures differ from LL-37’s helical peptide. LL-37 processing, PMID 8681941 · alpha-defensin structures, PMID 17088326

Question	LL-37	Alpha-defensins
Selected direct human evidence	Three native topical wound-trial populations, with mixed outcomes	HD5 expression in human intestinal tissue; other cited work examines structures and model systems
Mechanism example	Laboratory antimicrobial and context-dependent immune signaling	HD6 forms nanonets that entangle bacteria; family members differ
Therapeutic-claim grade	Low for broad wound or infection use	Very low for treating disease by administering the family

The LL-37 venous-ulcer pilot reported selected healing measures, whereas a subsequent 148-person trial found no significant full-cohort healing benefit. A diabetic-foot-ulcer cream study found a granulation signal but no significant reduction in measured aerobic bacterial colonization. These do not establish general anti-infective efficacy. LL-37 topical pilot, PMID 25041740 · larger phase IIb trial, PMID 34687253 · diabetic-foot-ulcer trial, PMID 37480520

The separate four-person intratumoral melanoma registry posts outcomes but cannot establish cancer efficacy or general safety. An oral study of engineered L. lactis expressing LL-37 is a different intervention, with no significant overall viral-negative-time result. NCT02225366 · PMID 37605995

HD6 experiments found nanonets around enteric pathogens in vitro and in vivo; the paper specifically reports little direct bactericidal activity for HD6. HD5 tissue-expression work in inflammatory bowel disease is a biomarker observation, not evidence that administering HD5 treats the disease. HD6 nanonets, PMID 22722251 · HD5 tissue study, PMID 28817680

Laboratory antimicrobial readouts, endogenous expression and topical trial outcomes address different questions. No direct LL-37-versus-alpha-defensin treatment trial was identified in these selected sources. FDA cites insufficient safety information for compounded LL-37; that assessment cannot be assigned to all alpha-defensin preparations. FDA compounding safety review

This comparison is educational and makes no treatment recommendation.

LL-37 vs Alpha-Defensins

LL-37

Alpha-Defensins

Biological identities

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