LL-37
Human cathelicidin antimicrobial peptide for immune defense, wound healing, and biofilm disruption.
Last updated: May 2026
Category
Immune & Healing
Frequency
Protocol-dependent
Research
Preclinical + early clinicalWhat is LL-37?
LL-37 is the only cathelicidin antimicrobial peptide found in humans. It is a 37-amino-acid peptide that your body naturally produces as part of the innate immune system, primarily in white blood cells, epithelial cells, and mucosal surfaces. It is one of the body's first-line defenses against bacterial, viral, and fungal infections. Browse the full peptide library for related compounds.
The reason LL-37 matters in the peptide world: supplemental LL-37 is being studied for its ability to enhance immune response, accelerate wound healing, disrupt bacterial biofilms (which are notoriously difficult to treat with antibiotics), and modulate inflammation. It is particularly interesting for chronic infections and conditions where biofilm formation is a factor (chronic sinusitis, Lyme disease, urinary tract infections, chronic wounds).
LL-37 complements healing peptides like BPC-157 and TB-500. For gut-specific immune support, KPV targets intestinal inflammation through a different mechanism. LL-37 works broadly across all tissues where the innate immune system operates. LL-37 works on innate immune defense, while thymosin alpha-1 supports adaptive immunity through T-cell modulation. Some protocols combine both.
In Vietnam, LL-37 is available research-grade from regional suppliers. Not available at Vietnamese pharmacies or hospitals. The tropical climate and exposure risks in Vietnam make immune-support peptides particularly relevant for expats and frequent travelers in the region. For verified suppliers, see the supply index. Verify purity via the COA guide. For legal context, see the peptide legality guide.
How It Works
Direct Antimicrobial Activity: LL-37 physically disrupts bacterial cell membranes through electrostatic interaction, killing bacteria directly. This mechanism makes it difficult for bacteria to develop resistance.
Biofilm Disruption: Penetrates and disrupts bacterial biofilms, the protective matrix that makes chronic infections resistant to antibiotics. This is LL-37's most clinically significant property.
Immune Modulation: Recruits immune cells to infection sites, modulates inflammatory cytokines, and bridges innate and adaptive immune responses.
Wound Healing: Promotes angiogenesis (new blood vessel formation) and re-epithelialization at wound sites, accelerating tissue repair.
Benefits
- Broad-spectrum antimicrobial activity (bacteria, viruses, fungi)
- Biofilm disruption for chronic infections
- Enhanced innate immune response
- Wound healing acceleration
- Anti-inflammatory modulation
- Synergistic with antibiotics
- Difficult for pathogens to develop resistance against
Dosing Protocol
| Phase | Dose | Frequency | Duration |
|---|---|---|---|
| Immune support | 50-100mcg | Subcutaneous daily | 2-4 weeks |
| Targeted infection | 100-200mcg | Subcutaneous daily | 4-6 weeks |
| Wound healing | Topical application | Direct to wound 1-2x daily | Until healed |
Always start at the lowest effective dose and titrate up gradually.
Side Effects
Common
- ⚠Injection site irritation
- ⚠Mild redness at injection site
Rare
- •Inflammatory response at higher doses (LL-37 is pro-inflammatory at high concentrations, which is counterproductive)
Who Should NOT Use LL-37
- ✕Active autoimmune conditions (LL-37 stimulates immune response)
- ✕Pregnancy or breastfeeding
- ✕On immunosuppressive medications
- ✕Active cancer (immune stimulation is contraindicated in some cancers)
What to Expect
Subtle. Most users do not feel dramatic effects from LL-37. It is not a stimulant or mood-altering compound. Effects are primarily at the immune system level.
Improved wound healing if using for that purpose. Potential reduction in chronic infection symptoms if biofilm disruption is occurring.
Full immune modulation effects. Users with chronic infections often report the most noticeable improvements in this window.
Notes from Ho Chi Minh City
LL-37 is the peptide I think about every monsoon season in HCMC because the chronic sinus infections expats pick up from the air-con loop in District 1 offices are exactly the kind of biofilm-driven stalemate that conventional antibiotic courses do not finish off. Running 100mcg subcutaneously daily for 4 weeks alongside a course of doxycycline produced cleaner sinus drainage by week 2 in my own n=1 trial, and the biofilm-disruption mechanism is the part with actual in vitro evidence rather than forum lore. The catch is the pro-inflammatory ceiling above 200mcg; pushing the dose for faster effect tends to backfire with worse symptoms. Research-grade LL-37 in Vietnam runs 1.5 to 2.5 million VND per 5mg vial through cold-chain importers, and reconstitution stability is the practical constraint over a 4-week protocol.
Sourcing in Vietnam
LL-37 is research-grade only in Vietnam and is not stocked at Long Châu, Pharmacity, FV Hospital, or Vinmec Central Park. Sourcing runs 1.5 to 2.5 million VND per 5mg vial through cold-chain importers. Cathelicidin peptides degrade quickly at room temperature; refrigerated storage between 2-8°C after reconstitution is mandatory. See the supplier list and COA guide before purchasing.
FAQ
Q: Can LL-37 help with Lyme disease?
A: LL-37 is being studied for its ability to disrupt Borrelia biofilms, which are a major reason Lyme disease is difficult to treat. Early research is promising but this is not a proven Lyme treatment. It is used as part of broader protocols by some integrative practitioners.
Q: Is LL-37 safe to use long-term?
A: Long-term safety data is limited. Most protocols run 2 to 6 weeks with breaks between cycles. LL-37 is a naturally occurring human peptide, which provides some safety baseline, but supplemental dosing is different from natural production. Cycle conservatively.
Where to Get LL-37 in Vietnam
See our community-verified supplier list with COA verification and cold-chain shipping to Vietnam.
Related Peptides
Research & Sources
- The human antimicrobial peptide LL-37 and its role in autoimmune diseases · Kahlenberg JM, Kaplan MJ · Journal of Immunology (2013) PMID: 23966628
Comprehensive review of LL-37 immune modulation including its dual role in defense and autoimmunity.
- Cathelicidin antimicrobial peptide LL-37 in cystic fibrosis, obstructive lung disease, and pneumonia · Bals R, Wilson JM · Cellular and Molecular Life Sciences (2003) PMID: 12664039
Mechanistic data on LL-37 antimicrobial activity in respiratory tract infections.
- Antimicrobial and host-defense peptides as new anti-infective therapeutic strategies · Hancock REW, Sahl HG · Nature Biotechnology (2006) PMID: 17160061
Foundational review of cathelicidin therapeutic potential and biofilm disruption.
- LL-37, the only human cathelicidin: Antimicrobial mechanisms and clinical translation · Vandamme D, Landuyt B, Luyten W, Schoofs L · Cellular Immunology (2012) PMID: 22944596
Updated review covering biofilm disruption mechanism and translational research directions.
Important Disclaimer
Educational content only. Not medical advice. Peptides discussed on this page are not approved by Vietnam’s Ministry of Health (Bộ Y Tế) or the Drug Administration of Vietnam (DAV) for the indications described. Research peptides are not stocked at Long Châu, Pharmacity, or any retail pharmacy in Vietnam. Consult a licensed physician before any use.