Recovery ⏱ Half-life: Variable depending on tissue context. Subject to proteolytic degradation but maintains activity in wound environments. Phase 2

LL-37

LL-37 (Cathelicidin)

Updated March 15, 2026

Evidence at a Glance

Regulatory statusPhase 2
Not FDA-approved; topical LL-37 (ropocamptide) reached Phase 2b for hard-to-heal venous leg ulcers; otherwise compounded/research use.
Human evidenceLimited
Animal evidenceModerate

LL-37 is the human cathelicidin antimicrobial peptide with promising antimicrobial and wound-healing data but only small early-phase topical trials and no approved indication.

What the research does not support

  • It is not FDA-approved for any use and is available only as a compounded or research-grade product.
  • Human evidence is limited to small topical wound-healing trials; injectable 'immune-boosting' or anti-aging uses are unproven.
  • At higher concentrations it can be cytotoxic and pro-inflammatory, so 'more is better' is false.
  • It has no controlled evidence for the fat-loss, longevity, or performance claims marketed online.
Half-Life
Variable depending on tissue context. Subject to proteolytic degradation but maintains activity in wound environments.
Mol. Weight
4493.33 g/mol

What is LL-37?

LL-37 is the sole member of the cathelicidin family of host defense peptides in humans. It serves as a critical first-line defense component of the innate immune system, with activity spanning antimicrobial defense, immune regulation, and tissue repair.

Research Applications

Antimicrobial defense research, wound healing, biofilm disruption, innate immunity studies, and vitamin D-immune axis research.

Dosage Information (Research Use)

Research protocols vary widely by application. Topical, subcutaneous, and in vitro concentrations documented in literature. Research use only.

Reconstitution & Handling

Standard BAC water reconstitution. Store carefully — larger peptide with potential for aggregation.

Half-Life & Pharmacokinetics

Variable depending on tissue context. Subject to proteolytic degradation but maintains activity in wound environments.

Reported Observations in Literature

As an endogenous peptide, generally well-tolerated at physiological concentrations. High concentrations can be cytotoxic to host cells in vitro. Research dosing focuses on staying within physiological ranges.

Key Research References

  • Vandamme D, et al. “A comprehensive summary of LL-37, the factotum human cathelicidin peptide.” Cell Immunol. 2012

How LL-37 Works

LL-37 is the only human cathelicidin antimicrobial peptide. It is cleaved from the precursor protein hCAP18 and has direct antimicrobial activity against bacteria, viruses, and fungi through membrane disruption. Beyond direct antimicrobial action, LL-37 modulates immune responses by recruiting immune cells, promoting angiogenesis, enhancing wound healing, and regulating inflammatory cytokine production.

Research Findings

Research interest in LL-37 spans infectious disease, wound healing, cancer biology (complex dual role), and inflammatory disorders. Vitamin D is the primary regulator of LL-37 expression in human tissues — the vitamin D-cathelicidin axis is a major area of innate immunity research.

Dosage & Administration

Research protocols vary widely by application. Topical, subcutaneous, and in vitro concentrations documented in literature. Research use only.

Safety & Side Effects

As an endogenous peptide, generally well-tolerated at physiological concentrations. High concentrations can be cytotoxic to host cells in vitro. Research dosing focuses on staying within physiological ranges.

Important: All safety information is derived from published research, primarily animal studies. No controlled human clinical trial data exists unless explicitly noted. This compound is sold for research purposes only.

Quick Facts

Sequence LLGDFFRKSKEKIGKEFKRIVQRIKDFLRNLVPRTES
Molecular Weight 4493.33 g/mol
Half-Life Variable depending on tissue context. Subject to proteolytic degradation but maintains activity in wound environments.
Available Sizes 5mg
Storage Lyophilized: -20°C. Reconstituted: 2-8°C.

Key Research References

  • Vandamme D, et al. "A comprehensive summary of LL-37, the factotum human cathelicidin peptide." Cell Immunol. 2012

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