Is LL-37 naturally produced by the body?

Yes. LL-37 is produced by epithelial cells, neutrophils, and other immune cells as part of the innate immune response. Vitamin D stimulates its endogenous production, which is one reason vitamin D status is linked to immune function.

How is LL-37 typically dosed in research?

Injectable research protocols typically use 100-200 mcg per injection SC, 1-3 times per week, cycling 2-4 weeks on with an equal break. Topical applications use 0.5-1% concentrations. Lower doses are safer and more physiologically mimetic of native cathelicidin responses.

Can LL-37 worsen autoimmune conditions?

Potentially yes. LL-37 can stimulate dendritic cells and inflammasomes (via P2X7 receptor), which could worsen symptoms in individuals with autoimmune predispositions or chronic inflammatory conditions. Systemic use should be avoided without medical oversight in these patients.

What is the recommended dose range for LL-37?

The research dose range is 50–100 mcg/day SC, administered via Subcutaneous, Once daily.

peptide dosing

LL-37 Dosing & Reconstitution Guide

Complete dosing reference for LL-37 (Antimicrobial / Immune). Covers reconstitution, dose range, titration schedule, pharmacokinetics, and storage protocols for research use.

Dosing Protocol

Route: Subcutaneous Frequency: Once daily Dose Range: 50–100 mcg/day SC Cycle Length: 4–8 weeks for acute infection support; longer for immune modulation Timing: Morning on empty stomach

Reconstitution

Vial Size: 5mg Water Volume: 2.5mL Concentration: 2mg/mL

Titration Schedule

Weeks 1–2: 50 mcg daily Weeks 3+: 100 mcg daily

Timeline & Pharmacokinetics

Onset: Hours (immune modulation) Peak Plasma: ~1–2 hours (SC) Half-Life: Short; rapidly degraded by proteases in vivo Time to Results: 1–4 weeks for immune support effects

Storage

Lyophilized: −20 °C (−4 °F) Reconstituted: 2–8 °C (35.6–46.4 °F) Shelf Life: 28 days

Injection Sites

Abdomen, Thigh

Safety & Contraindications

Safety: No large-scale completed human safety trials for systemic therapeutic use Endogenous peptide -- naturally produced; levels are tightly regulated in healthy tissue Injection site reactions: redness, itching, swelling due to mild inflammatory properties and local immune cell recruitment (~5-10% of users)

Contraindications: Autoimmune conditions (LL-37 can stimulate dendritic cells and inflammasomes via P2X7 receptor, potentially worsening symptoms); Rosacea (LL-37 overexpression is implicated in rosacea pathology); Pregnancy and breastfeeding (no safety data)

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Research Use Only. The information on this page is compiled from published research literature and is provided for educational purposes only. It does not constitute medical advice. All compounds referenced are intended for in vitro research use by qualified laboratories and institutions.