LL-37
Shop LL-37Also called: LL-37 , CAS: 154947-66-7, antimicrobial peptide, LL-37, human acetate, LL-37, human TFA
LL-37 is a natural germ-fighting substance that your own body makes. It is a tiny chain of building blocks called amino acids. It is part of your body's first line of defense against germs.
Scientists call it a host-defense peptide. LL-37 works by poking holes in the outer skins of bacteria and by calming swelling in the body. Research groups study it to learn how the body fights infections and helps wounds heal.
It is one of a small group of peptides studied for immune support. Most of the research so far comes from lab and animal studies, not large human trials. Scientists are still learning how safe and useful it might be in people. It is sold only as a research chemical and is not approved as a medicine.
Benefits
What LL-37 Helps With
The main themes across 131 research studies, in plain language.
Tissue & wound healing
Wound healing & tissue repair
85/100Rated 85/100Source typePeer-reviewed studyIndependent sources2Every claim links to the page it came from, and stronger sources rate higher. Full methodology →· 30 underlying claimsEvidence suggests LL-37 promotes wound healing by stimulating cell migration, proliferation, and the formation of new blood vessels.
Research examples
- Wound healing and reepithelization
- Induction of cell migration, proliferation, and differentiation
- Promotes new skin growth and cell migration
Chronic wound & ulcer support
40/100Rated 40/100Source typeVendor / seller pageIndependent sources3Every claim links to the page it came from, and stronger sources rate higher. Full methodology →· 6 underlying claimsClinical studies suggest topical application of LL-37 may improve healing rates in chronic wounds, such as diabetic foot and venous leg ulcers.
Immune modulation
Immune system modulation
90/100Rated 90/100Source typePeer-reviewed studyIndependent sources3Every claim links to the page it came from, and stronger sources rate higher. Full methodology →· 24 underlying claimsResearch points to LL-37 modulating immune responses by recruiting immune cells and regulating cytokines and chemokines.
Vitamin D pathway interaction
40/100Rated 40/100Source typeVendor / seller pageIndependent sources2Every claim links to the page it came from, and stronger sources rate higher. Full methodology →· 2 underlying claimsResearch confirms that Vitamin D3 upregulates the expression of LL-37, linking nutrient status to innate immune function.
Antimicrobial & antiviral
Broad-spectrum antimicrobial defense
90/100Rated 90/100Source typePeer-reviewed studyIndependent sources3Every claim links to the page it came from, and stronger sources rate higher. Full methodology →· 45 underlying claimsResearch suggests LL-37 acts as a broad-spectrum antimicrobial agent, targeting bacteria, fungi, and viruses through membrane disruption and direct killing mechanisms.
Biofilm disruption & prevention
90/100Rated 90/100Source typePeer-reviewed studyIndependent sources4Every claim links to the page it came from, and stronger sources rate higher. Full methodology →· 11 underlying claimsStudies indicate LL-37 can disrupt established bacterial biofilms and prevent new biofilm formation, potentially enhancing antibiotic efficacy.
Antiviral activity
72/100Rated 72/100Source typeEstablished referenceIndependent sources3Every claim links to the page it came from, and stronger sources rate higher. Full methodology →· 5 underlying claimsResearch indicates LL-37 exhibits antiviral effects against enveloped viruses, potentially by disrupting viral envelopes and triggering interferon responses.
Antibiotic resistance mitigation
40/100Rated 40/100Source typeVendor / seller pageIndependent sources3Every claim links to the page it came from, and stronger sources rate higher. Full methodology →· 5 underlying claimsResearch highlights LL-37's potential for a lower risk of resistance development compared to traditional antibiotics, as well as synergy with existing drugs.
Gut barrier & mucosal defense
50/100Rated 50/100Source typeUnclassified sourceIndependent sources3Every claim links to the page it came from, and stronger sources rate higher. Full methodology →· 4 underlying claimsResearch indicates LL-37 supports gut health by maintaining the integrity of the intestinal barrier and defending against pathogens.
Anti-inflammatory signaling
80/100Rated 80/100Source typePeer-reviewed studyIndependent sources3Every claim links to the page it came from, and stronger sources rate higher. Full methodology →· 7 underlying claimsStudies suggest LL-37 helps regulate inflammation, including neutralizing bacterial endotoxins and modulating inflammatory cytokines.
Cellular defense & cytoprotection
50/100Rated 50/100Source typeUnclassified sourceIndependent sources3Every claim links to the page it came from, and stronger sources rate higher. Full methodology →· 8 underlying claimsEvidence suggests LL-37 interacts with cell membranes and signaling pathways to support cellular defense mechanisms and reduce toxicity to host cells.
Angiogenesis & vascular growth
72/100Rated 72/100Source typeEstablished referenceIndependent sources3Every claim links to the page it came from, and stronger sources rate higher. Full methodology →· 6 underlying claimsStudies suggest LL-37 stimulates the formation of new blood vessels, which is a key part of tissue repair and wound healing.
Neuroprotection & mitochondrial support
30/100Rated 30/100Source typeForum or blogIndependent sources1Every claim links to the page it came from, and stronger sources rate higher. Full methodology →· 1 underlying claimPreliminary research suggests LL-37 may offer neuroprotective effects through interactions with mitochondrial mechanisms.
Skin health & cosmetic appearance
30/100Rated 30/100Source typeVendor / seller pageIndependent sources3Every claim links to the page it came from, and stronger sources rate higher. Full methodology →· 8 underlying claimsResearch suggests LL-37 may play a role in skin rejuvenation, including anti-aging, anti-wrinkle, and repair processes.
Anticancer & cytotoxic activity
85/100Rated 85/100Source typePeer-reviewed studyIndependent sources4Every claim links to the page it came from, and stronger sources rate higher. Full methodology →· 7 underlying claimsIn vitro research suggests LL-37 may induce cell death in certain cancer cell lines, though effects appear context-dependent.
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Safety
Known Side Effects
Adverse effects reported in the research and by community use.
- High toxicity to human cellsSevere 85/100Rated 85/100Source typePeer-reviewed studyIndependent sources1Every claim links to the page it came from, and stronger sources rate higher. Full methodology →↗ pmc.ncbi.nlm.nih.gov
- Susceptibility to proteolytic degradationModerateReported in 2 sources 85/100Rated 85/100Source typePeer-reviewed studyIndependent sources2Every claim links to the page it came from, and stronger sources rate higher. Full methodology →↗ pmc.ncbi.nlm.nih.gov↗ link.springer.com
- Induces inflammationMild 72/100Rated 72/100Source typeEstablished referenceIndependent sources1Every claim links to the page it came from, and stronger sources rate higher. Full methodology →↗ emedicine.medscape.com
- Permanent nail deformitySevere 72/100Rated 72/100Source typeEstablished referenceIndependent sources1Every claim links to the page it came from, and stronger sources rate higher. Full methodology →↗ dermnetnz.org
- Cytotoxicity towards human erythrocytes and keratinocytesModerate 72/100Rated 72/100Source typeEstablished referenceIndependent sources1Every claim links to the page it came from, and stronger sources rate higher. Full methodology →↗ link.springer.com
- erythemaMild 72/100Rated 72/100Source typeEstablished referenceIndependent sources1Every claim links to the page it came from, and stronger sources rate higher. Full methodology →↗ emedicine.medscape.com
- and telangiectasiaMild 72/100Rated 72/100Source typeEstablished referenceIndependent sources1Every claim links to the page it came from, and stronger sources rate higher. Full methodology →↗ emedicine.medscape.com
Reported in research and community sources — not exhaustive. Discontinue use and consult a healthcare professional if side effects occur.
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Compare research-grade suppliers with third-party COAs and published purity data. For in-vitro and laboratory research use only — not for human consumption, diagnosis, or treatment.
Technical Details (sequence & mechanism — click to expand)
Mechanism of Action
LL-37 is the active 37-amino-acid fragment of the human cathelicidin antimicrobial peptide (CAMP gene) and a key effector of innate immunity. It directly kills bacteria and fungi at skin/mucosal/wound sites and modulates immunity (chemokine induction, TLR signaling, angiogenesis). It is an endogenous host-defense peptide; therapeutic analogs are in development but it is not an approved drug.
Evidence
Research Citations (10)
Every claim above traces back to a source you can check — here are 10 of them.
- Source
The human cathelicidin LL-37: a multifunctional peptide involved in infection and inflammation in the lung.
Review2005 80/100Rated 80/100Source typePeer-reviewed studyIndependent sourcesstill being verifiedEvery claim links to the page it came from, and stronger sources rate higher. Full methodology → - Source
LL-37 | C205H340N60O53 | CID 16198951 - PubChem
95/100Rated 95/100Source typePeer-reviewed studyIndependent sourcesstill being verifiedEvery claim links to the page it came from, and stronger sources rate higher. Full methodology → - Source
Efficacy and safety of Oral LL-37 against the Omicron BA.5.1.3 variant of SARS-COV-2: A randomized trial
95/100Rated 95/100Source typePeer-reviewed studyIndependent sourcesstill being verifiedEvery claim links to the page it came from, and stronger sources rate higher. Full methodology → - Source
Evaluation of LL-37 in healing of hard-to-heal venous leg ulcers: A multicentric prospective randomized placebo-controlled clinical trial
95/100Rated 95/100Source typePeer-reviewed studyIndependent sourcesstill being verifiedEvery claim links to the page it came from, and stronger sources rate higher. Full methodology → - Source
Codelivery of 1α,25-dihydroxyvitamin D3 and CYP24A1 inhibitor VID400 by nanofiber dressings promotes endogenous antimicrobial peptide LL-37 induction
95/100Rated 95/100Source typePeer-reviewed studyIndependent sourcesstill being verifiedEvery claim links to the page it came from, and stronger sources rate higher. Full methodology → - Source
Human cathelicidin peptide LL-37 compacts nucleic acids and alters neutrophil extracellular trap structure
95/100Rated 95/100Source typePeer-reviewed studyIndependent sourcesstill being verifiedEvery claim links to the page it came from, and stronger sources rate higher. Full methodology → - Source
Between good and evil: Complexation of the human cathelicidin LL-37 with nucleic acids
95/100Rated 95/100Source typePeer-reviewed studyIndependent sourcesstill being verifiedEvery claim links to the page it came from, and stronger sources rate higher. Full methodology → - Source
Upregulating Human Cathelicidin Antimicrobial Peptide LL-37 Expression May Prevent Severe COVID-19 Inflammatory Responses and Reduce Microthrombosis
90/100Rated 90/100Source typePeer-reviewed studyIndependent sourcesstill being verifiedEvery claim links to the page it came from, and stronger sources rate higher. Full methodology → - Source
The Human Host-Defense Peptide Cathelicidin LL-37 is a Nanomolar Inhibitor of Amyloid Self-Assembly of Islet Amyloid Polypeptide (IAPP)
95/100Rated 95/100Source typePeer-reviewed studyIndependent sourcesstill being verifiedEvery claim links to the page it came from, and stronger sources rate higher. Full methodology → - Source
Evidence that the Human Innate Immune Peptide LL-37 may be a Binding Partner of Amyloid-β and Inhibitor of Fibril Assembly
95/100Rated 95/100Source typePeer-reviewed studyIndependent sourcesstill being verifiedEvery claim links to the page it came from, and stronger sources rate higher. Full methodology →
Timeline
History & Milestones
Key moments in LL-37’s research and regulatory timeline — sourced and dated.
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