Peptide research profile

LL-37

Also known as hCAP18-derived cathelicidin · CAP-18

The 37-residue human cathelicidin host-defense peptide. It has broad antimicrobial and immunomodulatory biology plus topical wound trials, but systemic use remains unestablished.

  • Immune & inflammation
Human trials3 referencesEducational use

Dosing literacy

Dosing & scaling, explained

The 100 mcg twice-daily calculator row is not the regimen used in human wound trials, which applied topical LL-37 at defined concentrations. This is educational source context—not a protocol or recommendation.

Scaling framework

How sourced amounts are organized

  1. Starting pointNot clinically established
    No validated titration window

    There is no regulator-approved starting dose for this research use. A low-looking number is not automatically safe.

  2. Recorded preset100 mcg twice daily
    Calculator library reference

    This is the range represented in the in-app protocol library. It describes the source record; it does not validate the regimen.

  3. Higher exposureNo systemic ceiling established
    Risk and uncertainty increase

    Higher exposure is not established as more effective. Human pharmacokinetic and long-term safety data may be absent.

Concentration applied to a wound (mg/mL) is not convertible to an injected whole-body dose using the calculator.

Schedule literacy

Patterns described in source material

  • Twice daily in the recorded preset

    The cadence represented by the recorded calculator presets.

  • Twice-weekly topical application in early wound trials

    Published experiments may use a different route, formulation, timing, or population and should not be treated as interchangeable.

  • No universal schedule

    No single schedule has been validated across products or research contexts.

Clinical context
  • 0.5–3.2 mg/mL · Topical, twice weeklyFirst-in-human venous-ulcer trialNot a systemic dose

Human evidence is route-specific: 0.5 and 1.6 mg/mL topical solutions showed early signals, while later results were mixed.

Research best practices

Storage, handling and interpretation

Lyophilized material

Keep cold, dry, and protected from light according to the manufacturer certificate or validated lab SOP.

After reconstitution

Use sterile technique, refrigerate as validated, and avoid repeated freeze–thaw cycles.

Traceability

Record lot, concentration, preparation date, and the identity/purity documentation used by the lab.

Research orientation

What researchers are exploring

These themes describe recurring questions in published research. They are not claims of effectiveness or recommendations for use.

  • 01

    Innate host defense

    Laboratory studies cover bacteria, fungi, viruses, biofilms, and membrane interactions.

  • 02

    Immune modulation

    LL-37 can act in pro- or anti-inflammatory directions depending on context.

  • 03

    Wound healing

    Topical trials evaluate hard-to-heal venous and diabetic ulcers.

  • 04

    Cancer biology

    Expression and signaling can be context-dependent and potentially bidirectional.

Evidence map

What the current evidence can support

Study models remain visible so laboratory and animal findings are not mistaken for established human outcomes.

  • Human

    Topical venous-ulcer trials

    A small phase I/II trial showed dose-dependent healing signals; a larger phase IIb study was negative overall.

  • Human

    Route-specific wound research

    Clinical evidence concerns local topical concentrations, not systemic injection.

  • Review

    Pleiotropic biology

    Reviews emphasize antimicrobial, chemotactic, angiogenic, and inflammatory effects that vary by environment.

Recorded protocol library

Amounts recorded for LL-37

These amount records are independent from vial strength, reconstitution volume and measuring device. A recorded source is not the same as study backing, and these values are not recommendations.

  • 01

    Recorded reference

    100 mcg

    Sign in for schedule, duration and source context.

  • 02

    Dose · upper endpoint

    500 mcg

    Sign in for schedule, duration and source context.

Technical reference

Identity, limitations and unknowns

Molecular profile

Class
Cationic human host-defense peptide
Sequence
LLGDFFRKSKEKIGKEFKRIVQRIKDFLRNLVPRTES
Amino acids
37
Approx. MW
4493.3 Da
Origin / design
Proteolytic product of the hCAP18 cathelicidin precursor

Important limitations

  • LL-37 can be cytotoxic or pro-inflammatory at some concentrations and contexts.
  • Proteolysis and formulation strongly influence local activity.
  • Topical mg/mL trial concentrations cannot validate injectable microgram dosing.
  • A calculator preset is a recorded research convention, not a recommendation or evidence of clinical benefit.
  • Identity, purity, sterility, and stability can vary substantially outside regulated manufacturing.
  • Route, formulation, and population can make results from one study inapplicable to another use.

Curated sources

3 curated references

  1. A comprehensive summary of LL-37, the factotum human cathelicidin peptideCellular Immunology · 2013 · Review
  2. Treatment with LL-37 is safe and effective in enhancing healing of hard-to-heal venous leg ulcersWound Repair and Regeneration · 2014 · Human
  3. Evaluation of LL-37 in healing of hard-to-heal venous leg ulcersWound Repair and Regeneration · 2021 · Human

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