ION BLUE EncyclopediaHigh Evidence

LL-37

LL-37 is the active fragment of the human cathelicidin antimicrobial peptide (hCAP18), an endogenous host-defense peptide. Research describes antimicrobial and immunomodulatory activity studied mainly in vitro and in animal models. Therapeutic applications are investigational and not approved.

Evidence: Preclinical

Reading time:1 min
Citations:2
Updated:June 29, 2026

Type

Peptide

Direct Answer

LL-37 is the active fragment of the human cathelicidin antimicrobial peptide (hCAP18), an endogenous host-defense peptide. Research describes antimicrobial and immunomodulatory activity studied mainly in vitro and in animal models. Therapeutic applications are investigational and not approved.

Summary Table

Evidence Level

High

Key Information

Classification

Antimicrobial Peptides2 Mechanisms

Key Takeaways

  • LL-37 is an endogenous human cathelicidin antimicrobial peptide
  • Antimicrobial and immune effects are described mainly in vitro and in animals
  • Therapeutic use is investigational and not approved

Scientific Overview

In Plain English

LL-37 is a small peptide the human body makes as part of its immune defenses. Laboratory and animal studies describe roles in fighting microbes and modulating inflammation. Using LL-37 as a therapy is still experimental and is not an approved treatment.

Scientific Details

LL-37 is a 37-residue cathelicidin-derived peptide with reported antimicrobial, immunomodulatory, and wound-related activity. Review literature describes pleiotropic effects, and animal studies have examined therapeutic potential, for example in sepsis models. Most evidence is preclinical, and clinical applications are investigational.

How It Works

Research describes LL-37 in relation to membrane-disruptive antimicrobial activity and immune signaling; these effects are characterized mainly in vitro and in animal models.

Mechanism of Action

Antimicrobial activity

cell

In vitro studies describe LL-37 in relation to disruption of microbial membranes.

Immunomodulation

cell

Research associates LL-37 with modulation of immune and inflammatory signaling.

Evidence Level

Human Evidence

LL-37 is an endogenous human peptide; therapeutic-use evidence in humans is limited and investigational.

Animal Evidence

Animal studies have examined LL-37 in models such as sepsis; review literature describes broader roles across immune, respiratory, gastrointestinal, and skin systems.

Cell Evidence

In vitro work characterizes antimicrobial and immunomodulatory activity.

Limitations

Most therapeutic evidence is preclinical; clinical use is not established and not approved.

References

  1. LL-37: Cathelicidin-related antimicrobial peptide with pleiotropic activity. Pharmacological Reports.Reviewdoi:10.1016/j.pharep.2016.03.015
  2. Therapeutic Potential of Cathelicidin Peptide LL-37, an Antimicrobial Agent, in a Murine Sepsis Model. International Journal of Molecular Sciences.Animal Studydoi:10.3390/ijms21175973

Alternative Names

  • Cathelicidin LL-37
  • hCAP18/LL-37
  • Cathelicidin antimicrobial peptide

Claim Boundaries

ION BLUE is an educational research aggregator. This content summarizes published scientific literature. It is not medically reviewed, is not medical advice, and is not a recommendation to use any substance. Several peptides discussed are research chemicals not approved for human use. Consult a licensed healthcare provider. This entry summarizes preclinical literature; it is not a recommendation to obtain or use LL-37.

This page summarizes published research and is for informational purposes only; it is not medical advice.