LL-37 Tracker App
Log Doses, Monitor Infection Markers, and Track Immune Support Response
LL-37 is the only human cathelicidin antimicrobial peptide — a 37-amino-acid innate immune defence molecule naturally secreted by neutrophils, epithelial cells, and NK cells in response to infection and injury. It exhibits direct antimicrobial activity against bacteria, viruses, and fungi, disrupts pathogenic biofilms, modulates innate immune signalling, and promotes wound healing. Shotlee tracks every LL-37 dose, infection marker, immune lab value, and healing metric in one free app.
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What Is LL-37?
LL-37 is the sole human cathelicidin, produced from the hCAP18 precursor protein via neutrophil elastase cleavage. Named for its 37-amino-acid length beginning with two leucines (LL), it is a key component of innate immune defence — deployed at skin barriers, mucosal surfaces, and wound sites. LL-37 levels are naturally upregulated by vitamin D3 and by acute infection signals.
Beyond direct antimicrobial activity, LL-37 modulates immune signalling: it acts as a chemoattractant for monocytes and neutrophils, promotes dendritic cell maturation, and stimulates angiogenesis and keratinocyte migration for wound closure. Its anti-biofilm activity is of particular interest in the context of chronic infections involving antibiotic-resistant biofilm-forming bacteria such as Pseudomonas aeruginosa and Staphylococcus aureus.
Research Peptide — Not Approved for Human Use
Exogenous LL-37 peptide is not approved for human use by the FDA or in most jurisdictions. Evidence is primarily from preclinical and early-phase research. Consult a licensed physician before considering any peptide protocol.
Protocol Options
100 mcg
Subcutaneous, once daily
Lower-end dose used for general immune modulation and antimicrobial support. Often used as a starting dose to assess individual tolerance.
300 mcg
Subcutaneous, once daily
Higher research dose for chronic infection support, anti-biofilm applications, or wound healing acceleration. Typical cycle: 4–8 weeks.
Mechanism of Action
Disrupts microbial cell membrane integrity via electrostatic interaction with negatively charged bacterial and fungal membranes — physical membrane disruption rather than enzymatic targeting, reducing resistance risk.
Neutralises lipopolysaccharide (LPS) from gram-negative bacteria, blocking TLR4 activation and preventing the systemic inflammatory cascade that drives septic shock.
Acts as an immune chemoattractant: recruits monocytes, T cells, and mast cells to infection sites via formyl peptide receptor-like 1 (FPRL1) binding.
Promotes wound closure and angiogenesis by stimulating keratinocyte migration and proliferation and upregulating VEGF expression — bridging innate immunity and tissue repair.
Research Highlights
Antimicrobial Breadth
Broad
Active against gram-positive and gram-negative bacteria, fungi, and enveloped viruses (including influenza and HIV) in in vitro models.
Anti-Biofilm
Yes
Disrupts established biofilms of P. aeruginosa and S. aureus at concentrations that do not affect planktonic bacteria — uniquely targeting the antibiotic-resistant biofilm phenotype.
Wound Healing
Dual
Simultaneously provides antimicrobial protection at wound sites and stimulates keratinocyte migration and angiogenesis — combining infection control with tissue repair.
What to Track in Shotlee
Build a complete antimicrobial and immune support diary — doses, infection markers, wound progress, and immune labs.
Dose Logs
Record every LL-37 injection: date, dose (mcg), site, and lot number. Never lose your protocol history across a multi-week cycle.
Infection Markers
Log lab values: WBC count, CRP, procalcitonin, and any culture results. Track how infection markers respond to your protocol over time.
Wound Photos
Attach timestamped wound photos to your Shotlee logs. Visual healing evidence alongside dose logs creates a compelling before/after timeline.
Immune Lab Work
Record WBC differential, CRP, and immunoglobulin levels from clinic visits. Document your immune status baseline before and during protocol.
Energy Ratings
Log daily energy and fatigue on a 0–10 scale. Chronic infection and immune dysregulation both heavily impact energy — track recovery.
Symptom Diary
Record symptom type, severity, and location daily. Detailed symptom logs help correlate LL-37 dosing timing with clinical response.
LL-37 for Chronic Infections and Anti-Biofilm Applications
Chronic infections — particularly those involving biofilm-forming organisms — represent a significant gap in conventional antibiotic therapy. Biofilms protect bacteria from both immune clearance and antibiotic penetration by orders of magnitude. LL-37 disrupts biofilm matrix integrity through a different mechanism than conventional antibiotics, making the combination potentially synergistic.
Some researchers exploring LL-37 for chronic sinus infections, recurrent UTIs, or wound infections log simultaneous conventional antibiotic use alongside LL-37 doses in their Shotlee tracker. This allows retrospective analysis of whether combination protocols correspond to faster symptom resolution compared to antibiotic-only cycles.
Track Alongside Antibiotics in Shotlee
If combining LL-37 with conventional antibiotics, log both in Shotlee with start/stop dates. This creates a clear timeline for attributing treatment response.
Protocol FAQs
LL-37 is the only human cathelicidin antimicrobial peptide. In preclinical research it is studied for broad-spectrum antimicrobial activity, anti-biofilm effects (particularly against antibiotic-resistant bacteria), immune modulation, and wound healing acceleration. It is not approved for human use.
Research protocols typically use 100–300 mcg subcutaneously once daily, with cycles of 4–8 weeks. Lower doses (100 mcg) are often used as starting points to assess individual tolerance before escalating.
LL-37 disrupts bacterial cell membranes physically, rather than targeting specific enzymatic processes. This broad membrane disruption mechanism reduces the likelihood of resistance development. It also targets biofilms, which conventional antibiotics typically cannot penetrate effectively. LL-37 additionally has immune-modulatory effects that antibiotics lack.
Key markers include WBC and differential (immune activity), CRP (systemic inflammation), and procalcitonin (bacterial infection severity). For wound applications, wound measurement and photography provide the most direct evidence of response. Log all results with dates in Shotlee.
LL-37 and Thymosin Alpha-1 are frequently considered together — LL-37 provides direct antimicrobial and anti-biofilm defence while Thymosin Alpha-1 strengthens adaptive immune responses (T cell maturation, NK cell activity). Log each compound separately in Shotlee to track individual contributions.
References
- [1]ReviewVandamme D, et al. "A comprehensive summary of LL-37, the factotum human cathelicidin peptide." Cell Immunol. 2012;280(1):22-35.
- [2]ReviewMookherjee N, Hancock RE. "Cationic host defence peptides: innate immune regulatory peptides as a novel approach for treating infections." Cell Mol Life Sci. 2007;64(7-8):922-33.
- [3]Clinical TrialRaqib R, et al. "Improved outcome in shigellosis associated with butyrate induction of an endogenous peptide antibiotic." Proc Natl Acad Sci USA. 2006;103(24):9178-83.
Track Your LL-37 Protocol in Shotlee
Log doses, monitor WBC and CRP, document wound healing photos, and track your immune support response — all free in Shotlee.
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