LL-37 is the only human cathelicidin antimicrobial peptide and plays several roles in innate immunity. Laboratory research documents antimicrobial and immune-signaling activity, but those findings do not establish a therapeutic effect. No LL-37 product is FDA-approved.
Antimicrobial peptide (cathelicidin)
LL-37
LL-37 is the only human cathelicidin antimicrobial peptide and plays several roles in innate immunity. Laboratory research documents antimicrobial and immune-signaling activity, but those findings do not establish a therapeutic effect. No LL-37 product is FDA-approved.
Regulatory watch
Last reviewed Jul 1, 2026
Next review Jul 29, 2026
Evidence snapshot
LL-37 is the sole human cathelicidin antimicrobial peptide, with well-characterized broad-spectrum activity against bacteria, fungi, and enveloped viruses in laboratory studies.
Dürr et al. (2006) published a foundational review in Biochimica et Biophysica Acta describing LL-37's structure, mechanism, and biological roles as the only human cathelicidin.
Kahlenberg & Kaplan (2013) reviewed LL-37's dual role in innate immunity and autoimmunity in the Journal of Immunology, noting both protective antimicrobial effects and pro-inflammatory potential in autoimmune disease.
LL-37 is not FDA-approved for any indication. No approved therapeutic products containing LL-37 are marketed in the United States. ClinicalTrials.gov lists limited interventional studies.
The biohacking community has adopted LL-37 for self-directed immune support and wound healing, despite the absence of clinical trial data supporting its safety or efficacy in these contexts.
Research record
What the evidence record says
- Evidence grade
- Not Graded
- Regulatory status
- LL-37 regulatory status has not been fully reviewed by Peptide Report editorial team. See company profiles and regulatory watch for current status.
Evidence records
Studies, registries, reviews, and regulatory records
Evidence review pending
- Detailed evidence review for LL-37 is pending editorial assessment. Current summary reflects available public records.
Records: LL-37, the only human member of the cathelicidin family of antimicrobial peptides, Little Peptide, Big Effects: Defining New Roles for LL-37 in Autoimmunity, LL-37 Clinical Trial Registry Entries: ClinicalTrials.gov
Evidence timeline
What changed, and when
Peptide Report last reviewed LL-37 on 2026-07-01.
Records: LL-37, the only human member of the cathelicidin family of antimicrobial peptides
Direct answers
Frequently asked questions
What is LL-37?
LL-37 is a antimicrobial peptide (cathelicidin) tracked by Peptide Report. See the full profile for current editorial assessment.
Open research questions
What is still unknown
- What is the complete human evidence base for LL-37?
- What are the long-term safety considerations for LL-37?
Tracked claims
LL-37 has demonstrated broad-spectrum antimicrobial activity against bacteria, fungi, and viruses in laboratory studies.
Evidence level: Peer reviewed
Sources: LL-37, the only human member of the cathelicidin family of antimicrobial peptides, Little Peptide, Big Effects: Defining New Roles for LL-37 in Autoimmunity
How to read this: Laboratory antimicrobial activity does not establish clinical efficacy. Do not translate in vitro findings into treatment claims without clinical trial evidence.
LL-37 is not FDA-approved and no approved therapeutic products containing LL-37 are available in the US.
Evidence level: Primary regulatory
Sources: LL-37 Clinical Trial Registry Entries: ClinicalTrials.gov, FDA BPC-157 compounding safety risk: immunogenicity
How to read this: Verify current regulatory status and any FDA compounding or safety listings on each review cycle. Update if clinical trial programs advance to approval.
The biohacking community uses LL-37 for immune support and wound healing despite a lack of clinical trial evidence.
Evidence level: Community discussion
Sources: LL-37 Clinical Trial Registry Entries: ClinicalTrials.gov, FDA BPC-157 compounding safety risk: immunogenicity
How to read this: Track community interest as a public claim signal. Do not endorse or amplify self-directed use. The FDA has identified certain bulk peptide substances as potentially presenting significant safety risks in compounding.
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Sources on this page
Each source record is linked to the claim or evidence note it supports.
LL-37, the only human member of the cathelicidin family of antimicrobial peptides
Dürr UHN, Sudheendra US, Ramamoorthy A (2006) foundational review (PMID 16459200) of LL-37 structure, mechanism, broad-spectrum antimicrobial activity, and role as the sole human cathelicidin.
6 linked pagesOpen original ·
pubmed-durr-ll37-2006Little Peptide, Big Effects: Defining New Roles for LL-37 in Autoimmunity
Kahlenberg JM, Kaplan MJ (2013) review (PMID 23836012) of LL-37's dual role in innate immunity and autoimmunity, describing both protective antimicrobial effects and pro-inflammatory potential in autoimmune disease.
5 linked pagesOpen original ·
pubmed-kahlenberg-ll37-2013LL-37 Clinical Trial Registry Entries: ClinicalTrials.gov
ClinicalTrials.gov registry search for interventional studies involving LL-37/cathelicidin, showing limited clinical trial activity. LL-37 is not FDA-approved for any indication.
6 linked pagesOpen original ·
clinicaltrials-gov-ll-37Certain bulk drug substances for use in compounding may present significant safety risks
FDA risk page lists BPC-157: compounded BPC-157 may pose immunogenicity risk and peptide-related impurity concerns for certain routes of administration.
41 linked pagesOpen original ·
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