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May 29, 2025

LL-37: The Antimicrobial Peptide for Immune and Skin Health

LL-37 is a natural antimicrobial peptide that enhances the immune system and promotes skin repair. Discover how LL-37 peptide therapy, combined with other healing peptides, is helping patients overcome chronic infections, skin inflammation, and immune dysfunction.

LL-37: The Antimicrobial Peptide for Immune and Skin Health

LL-37: The Antimicrobial Peptide That Supports Immunity and Skin Health

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LL-37 is a powerful antimicrobial peptide that defends the body against infections while also supporting skin healing and immune modulation. Learn how LL-37 and other peptide therapies are transforming treatment for chronic infections, skin disease, and immune dysfunction.

Introduction: What Is LL-37?

LL-37 is one of the body’s most dynamic and clinically promising antimicrobial peptides (AMPs). Naturally produced by immune and epithelial cells, it provides a powerful defense against bacteria, viruses, and fungi—while also modulating inflammation and enhancing skin repair.

What sets LL-37 apart from traditional antibiotics or steroid therapies is its ability to support both innate immunity and tissue regeneration without suppressing the immune system. As part of the body’s frontline response, LL-37 not only kills pathogens but also promotes healing and immune balance.

In this article, we’ll explore the science of LL-37, its therapeutic benefits, and how it fits into integrative care for conditions like chronic infections, eczema, acne, wound healing, and autoimmunity. You’ll also discover how LL-37 peptide therapy is being used clinically to restore health from the inside out.

The Science Behind LL-37: Origins and Function

LL-37 is the only known human cathelicidin-derived peptide. It is generated from a larger precursor protein, hCAP18, which is cleaved enzymatically to produce active LL-37.

Where is LL-37 produced?

  • Skin (keratinocytes)

  • Lungs and airways

  • GI tract lining

  • Reproductive tract

  • Immune cells like neutrophils and macrophages

Its expression is enhanced by vitamin D, immune activation, and tissue injury—making it a cornerstone of innate immune defense.

LL-37’s Antimicrobial Superpowers

LL-37 exhibits broad-spectrum antimicrobial activity:

  • Gram-positive bacteria – Staphylococcus aureus, Streptococcus

  • Gram-negative bacteria – E. coli, Pseudomonas aeruginosa

  • Viruses – Influenza, RSV, herpes simplex

  • Fungi – Candida species

  • Mycobacteria – M. tuberculosis

Its mechanism of action involves disrupting microbial membranes, neutralizing endotoxins like LPS, and breaking down biofilms, which are notoriously difficult to treat with antibiotics.

Unlike conventional antimicrobials, LL-37 is much less prone to resistance—a crucial benefit in an era of antibiotic overuse and superbugs.

Immunomodulatory Effects of LL-37

Beyond infection-fighting, LL-37 has a profound effect on immune system regulation:

  • Promotes chemotaxis of immune cells to injury or infection

  • Enhances antigen presentation via dendritic cell activation

  • Regulates cytokine levels—balancing pro- and anti-inflammatory signals

  • Neutralizes inflammatory endotoxins (like LPS)

  • Supports tissue repair and epithelial regeneration

This means LL-37 can be beneficial in conditions that involve chronic inflammation, immune dysregulation, and barrier dysfunction.

LL-37 and Skin Health

LL-37 plays a major role in skin defense and repair, with mounting evidence showing benefit in the following conditions:

1. Wound Healing

LL-37 enhances re-epithelialization and angiogenesis—key steps in tissue regeneration. It also reduces the bacterial load in wounds and may accelerate healing of:

  • Diabetic ulcers

  • Post-surgical wounds

  • Burns

  • Chronic pressure sores

2. Eczema / Atopic Dermatitis

People with eczema often have low LL-37 levels, contributing to poor barrier function and increased risk of skin infections.

By restoring LL-37 levels through peptide therapy or vitamin D optimization, it’s possible to reduce inflammation and infection risk without steroids.

3. Psoriasis

Interestingly, LL-37 is elevated in psoriatic lesions, where it may form complexes with self-DNA, triggering autoimmunity. In these cases, therapies that modulate LL-37 activity (rather than boosting it) may be more appropriate.

4. Acne and Rosacea

LL-37 suppresses Propionibacterium acnes and reduces inflammation in acne. In rosacea, improperly processed LL-37 fragments may exacerbate symptoms—making controlled delivery through peptide therapy more desirable than topical overexpression.

Chronic Infections and LL-37

Chronic infections often involve biofilms, antibiotic resistance, and immune evasion. LL-37 can target all three.

1. Lyme Disease and Co-infections

LL-37 has shown activity against Borrelia burgdorferi and may help patients with chronic Lyme by penetrating biofilms and enhancing immune clearance.

2. Chronic Sinusitis and Respiratory Infections

LL-37 helps regulate mucosal immunity, reduces microbial colonization, and modulates inflammation—making it valuable in recurrent upper respiratory infections.

3. Urinary Tract Infections (UTIs)

LL-37 is naturally produced in the urinary tract and helps prevent bacterial adhesion. LL-37 therapy may be helpful for women with chronic or postmenopausal UTIs.

Autoimmunity and LL-37: Caution and Opportunity

While LL-37 generally supports immune balance, its role in autoimmunity is context-dependent. In lupus, psoriasis, or inflammatory bowel disease, overactive or misdirected LL-37 may contribute to immune activation.

However, in the right dose and delivery route, LL-37 can actually suppress autoimmune inflammation, promote regulatory immune cell development, and heal damaged tissue.

This dual action makes it a powerful but nuanced tool—best used under clinical guidance.

Peptide Therapy: How LL-37 is Used Clinically

LL-37 peptide is available by prescription and typically used under physician supervision.

Modes of administration:

  • Subcutaneous injection – Most common and systemic

  • Topical gel – For local wound healing or skin infections

  • Intranasal or oral mucosal – Investigational routes for sinus and respiratory conditions

Dosage and frequency vary depending on the condition being treated. A typical protocol may involve 3–5 doses per week, often in combination with lifestyle or nutritional interventions.

👉 Learn more or request an evaluation:
LL-37 Peptide Therapy at Revolution Health

Synergistic Peptides and Supportive Therapies

Several other peptides may work synergistically with LL-37 to accelerate healing or immune regulation:

🧬 BPC-157

Supports gastrointestinal and epithelial healing. Often combined with LL-37 for skin or gut conditions.

🧬 KPV

A tripeptide with potent anti-inflammatory effects. Helpful for eczema, IBD, and inflammatory skin disorders.

🧬 TB-500 (Thymosin Beta-4)

Improves tissue regeneration and reduces fibrosis. Useful for chronic wounds or muscle/tendon repair.

Nutritional and Lifestyle Synergy

LL-37 expression can be enhanced through natural means, which may complement peptide therapy:

  • Vitamin D3 – Stimulates natural cathelicidin expression

  • Zinc – Supports immune function and wound repair

  • NAC and glutathione – Reduce oxidative stress

  • Omega-3s – Anti-inflammatory and skin supportive

  • Good gut health – Reduces systemic inflammation and improves immune regulation

Also important: regular movement, stress reduction, and a clean diet free of inflammatory processed foods.

Is LL-37 Right for You?

Consider LL-37 therapy if you struggle with:

  • Recurrent or chronic infections

  • Difficult-to-heal wounds

  • Eczema, acne, or rosacea

  • Immune imbalance or autoimmune disease

  • Antibiotic resistance or biofilm-associated infections

An experienced functional or integrative provider can evaluate your labs, history, and current symptoms to determine if LL-37 is a fit for your protocol.

Real-World Case: Skin and Immunity Restored

A 44-year-old woman presented with chronic eczema, antibiotic-resistant staph colonization, and fatigue. After initiating:

  • LL-37 200 mcg SC 3x/week

  • BPC-157 for gut and barrier repair

  • Vitamin D repletion and omega-3 support

Her eczema improved within 4 weeks, with no further infections over 3 months. Fatigue and mood also improved—highlighting LL-37’s whole-body benefits.

Final Thoughts: LL-37’s Role in Modern Healing

In a medical landscape dominated by pharmaceuticals that suppress symptoms, LL-37 offers a biologically intelligent tool—supporting the body’s innate ability to defend, repair, and rebalance.

From skin health to immunity, from infection control to autoimmunity modulation, LL-37 stands out as a cornerstone peptide in regenerative and functional medicine.

Ready to Explore Peptide Therapy?

Revolution Health offers personalized peptide protocols backed by clinical expertise and cutting-edge testing. Discover whether LL-37 or other peptides like BPC-157 or TB-500 can support your healing journey.

References

  1. Doss M, et al. "The human antimicrobial peptide LL-37, a multifunctional modulator of the innate immune response." Int J Antimicrob Agents.

  2. Mookherjee N, et al. "Modulation of the TLR-mediated inflammatory response by the endogenous human host defense peptide LL-37." J Immunol.

  3. Sørensen OE, et al. "Wound healing and expression of antimicrobial peptide LL-37 in human keratinocytes." J Biol Chem.

  4. Kahlenberg JM, Kaplan MJ. "Little peptide, big effects: LL-37 in inflammation and autoimmunity." J Immunol.

  5. Dean SN, Bishop BM, van Hoek ML. "Natural and synthetic cathelicidin peptides with antimicrobial and antibiofilm activity against Staphylococcus aureus." BMC Microbiology.