LL-37

Early human Immune Support In 1 protocol 3 sources

LL-37 is the only human cathelicidin antimicrobial peptide, naturally produced by the body's immune cells. Research shows it possesses broad-spectrum antimicrobial properties against bacteria, fungi, and viruses, while also playing a crucial role in immune modulation, reducing inflammation, and accelerating wound healing.

01Dosing reference

Amount

100-250 mcg/day

Frequency

Once daily

Cycle

2-4 weeks on, followed by evaluation

Reference figures, not a recommendationThese values reflect amounts described in the literature and vendor documentation this database indexes. Use the reconstitution calculator to convert them into syringe units.

02Mechanism of action

Membrane Binding and Disruption

As a cationic peptide, LL-37 binds to the negatively charged membranes of pathogens and disrupts their structural integrity.

Immune Receptor Activation

It interacts with host cell receptors like FPRL1 to stimulate the migration of immune cells (chemotaxis) to the site of infection.

Wound Healing and Angiogenesis

It promotes the proliferation of epithelial cells and the formation of new blood vessels, accelerating tissue repair and clearing biofilms.

03Human evidence

Intra-tumoral injections of LL-37 were evaluated in a Phase 1 clinical trial for melanoma patients with cutaneous metastases, demonstrating safety and potential immune activation.

Phase 1 trial (NCT02225366) focusing on safety and tolerability in a specific cancer population.

Topical application of LL-37 has been investigated for the treatment of hard-to-heal venous leg ulcers, showing promise in promoting wound closure.

Early clinical studies evaluating localized application for chronic wounds, limited by small sample sizes.

04Preclinical evidence

LL-37 effectively neutralized endotoxins (LPS) and reduced systemic inflammation in murine models of sepsis.

Animal models of severe bacterial infection, demonstrating potential protective effects against septic shock.

In vitro studies demonstrated that LL-37 stimulates airway epithelial cell proliferation and migration, aiding in respiratory tissue repair.

Cell culture models highlighting its role in epithelial regeneration beyond direct antimicrobial action.

05What is known vs. unknown

Reasonably established

LL-37 is an endogenous human antimicrobial peptide produced by immune cells like neutrophils and macrophages.
It exhibits broad-spectrum activity against Gram-positive and Gram-negative bacteria, including some antibiotic-resistant strains.
Beyond killing pathogens, it acts as an immunomodulator that promotes wound healing and angiogenesis.
It has the ability to disrupt and prevent the formation of bacterial biofilms, which are notoriously difficult to treat.

Unknowns & limits

The optimal dosing and delivery method for systemic infections in humans remains unclear due to potential peptide degradation by proteases in the blood.
High concentrations of LL-37 may be cytotoxic to host cells or potentially exacerbate certain autoimmune conditions like psoriasis.

06Safety & regulatory context

Regulatory statusLL-37 is generally considered safe in early clinical trials when used as a topical application or localized injection. However, systemic administration may carry risks of injection site reactions, potential cytotoxicity at high doses, and theoretical risks of exacerbating autoimmune diseases due to its immunomodulatory effects. It is not FDA-approved for any medical condition and remains an investigational compound for research purposes only.

07Compared with BPC-157

LL-37 vs. BPC-157

Key difference

While BPC-157 primarily focuses on systemic tissue, tendon, and gut healing through angiogenesis and nitric oxide pathways, LL-37 is primarily an antimicrobial and immune-modulating peptide that directly kills pathogens while aiding localized wound repair.

When researchers discuss each

BPC-157 is typically discussed for musculoskeletal injuries and gut inflammation, whereas LL-37 is discussed for chronic infections, biofilms, and hard-to-heal infected wounds.

08Appears in protocols

🛡️ Immune Defense Protocol

100 mcg/dayDaily

09Glossary

Cathelicidin

A family of antimicrobial peptides found in immune cells that play a critical role in the innate immune defense against bacterial infections.

Antimicrobial Peptide (AMP)

Small proteins that are part of the innate immune response, capable of killing a wide range of pathogens including bacteria, viruses, and fungi.

Biofilm

A structured community of microorganisms encapsulated within a self-developed protective matrix, making them highly resistant to standard antibiotics.

10Knowledge check

Q1What is the primary direct mechanism by which LL-37 combats bacterial infections?

Q2Besides its direct antimicrobial properties, what other significant role does LL-37 play in the body?

Q3When interpreting the human data on topical LL-37 for hard-to-heal venous leg ulcers, which conclusion is most consistent with the dossier's description of that evidence?

Q4Which statement best captures the documented comparison between LL-37 and BPC-157 in the dossier?

Q5Which statement about LL-37’s regulatory status and safety concerns is supported by the dossier?

11Sources

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Research and educational use onlyNothing on this site is medical advice, a prescription, or a recommendation for human use. Compounds documented here are research chemicals. Consult a qualified clinician before making any health decision.