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LL-37

FDA: research-only
Last updated · 2026-04-12

LL-37 is a cathelicidin antimicrobial peptide involved in innate immunity that destroys bacteria, modulates inflammation, and supports tissue repair. Found naturally in neutrophils and epithelial tissues, it is used for gut healing, skin conditions, and immune rebalancing. Antimicrobial peptide that restores microbiome balance, suppresses fungal overgrowth, and clears bacterial overgrowth. Heals leaky gut and retrains immune tolerance. Destroys bacteria directly while modulating inflammatory response. Found naturally in neutrophils and epithelial tissues. - SIBO treatment and candida/yeast control - Skin conditions (acne, eczema, rosacea) - Post-antibiotic gut restoration - Gut immune healing and leaky gut repair - Food sensitivity reduction -

This content is for educational and research purposes only. VialBase does not provide medical advice. Consult a healthcare professional before using any peptide.

Molecular weight —
Half-life —
CAS number 154947-66-7
Route —
Where to buy LL-37 →BioLongevity Labs · save 15% code VIALBASE
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Research summary

Study Type Year Key Finding
Cathelicidin LL-37: a multitask antimicrobial peptide. Narrative review 2010 Narrative review, not primary or clinical data — it summarizes LL-37 biology rather than testing an intervention
The Potential of Human Peptide LL-37 as an Antimicrobial and Anti-Biofilm Agent. Narrative review 2021 Narrative review of LL-37 as a candidate antibiotic alternative — not primary or clinical data
Efficacy of LL-37 cream in enhancing healing of diabetic foot ulcer: a randomized double-blind controlled trial. Randomized, double-blind, placebo-controlled human trial (topical cream) 2023 Randomized double-blind controlled trial in humans (Jakarta, January 2020 to June 2021; ClinicalTrials.gov NCT04098562) of topical LL-37 cream versus placebo cream, applied twice a week for 4 weeks in diabetic foot ulcer with mild infection
Exploring the Antimicrobial Potential of LL-37 Derivatives: Recent Developments and Challenges. Narrative review 2025 Narrative review of LL-37 derivatives and modification strategies — not primary or clinical data

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What bloodwork do I need?

Reference ranges are general guidelines. Consult your physician for interpretation.

PRE-CYCLE
  • CMP
  • CBC with differential
  • CRP
  • ESR
DURING CYCLE
  • CBC with differential
  • CRP
POST-CYCLE
  • CMP
  • CBC
  • CRP
Safety & Regulatory Status
FDA STATUS research-only

Regulatory status for LL-37 may change. Verify current status with your jurisdiction before use. This is not legal or medical advice.

Frequently Asked Questions

What is LL-37?
LL-37 is a cathelicidin antimicrobial peptide involved in innate immunity that destroys bacteria, modulates inflammation, and supports tissue repair. Found naturally in neutrophils and epithelial tissues, it is used for gut healing, skin conditions, and immune rebalancing.
How does LL-37 work?
Antimicrobial peptide that restores microbiome balance, suppresses fungal overgrowth, and clears bacterial overgrowth. Heals leaky gut and retrains immune tolerance. Destroys bacteria directly while modulating inflammatory response.
How is LL-37 dosed?
Systemic: 50-100 mcg SubQ 2-3x/week (cycle 2-3 weeks); Spot dose: 50 mcg SubQ near lesion for acne (not systemic); Gut healing: 50-100 mcg 2-3x/week (inject or oral); Range: 100-500 mcg in research settings; Route: SubQ (spot and systemic), topical. These figures reflect commonly cited research protocols, not medical advice — consult a clinician.
Is LL-37 FDA-approved?
LL-37 is a research-only compound and is not FDA-approved. Research-only — not FDA-approved for human use; Endogenous antimicrobial peptide (naturally occurring); Available through research chemical suppliers.

References

  1. Bucki R, Leszczyńska K, Namiot A, et al.. Cathelicidin LL-37: a multitask antimicrobial peptide.. Archivum immunologiae et therapiae experimentalis (2010). PMID: 20049649
  2. Ridyard KE, Overhage J. The Potential of Human Peptide LL-37 as an Antimicrobial and Anti-Biofilm Agent.. Antibiotics (Basel, Switzerland) (2021). PMID: 34072318
  3. Miranda E, Bramono K, Yunir E, et al.. Efficacy of LL-37 cream in enhancing healing of diabetic foot ulcer: a randomized double-blind controlled trial.. Archives of dermatological research (2023). PMID: 37480520
  4. Yuan Y, Li J, Wei G, et al.. Exploring the Antimicrobial Potential of LL-37 Derivatives: Recent Developments and Challenges.. ACS biomaterials science & engineering (2025). PMID: 40423576