🔬 Antimicrobial & Immune Peptide

LL-37 (5 mg Vial) Dosage Protocol

LL-37 is the only human cathelicidin antimicrobial peptide — a 37-amino acid helical peptide derived from the C-terminal cleavage of the hCAP18 precursor protein. It is produced by neutrophils, epithelial cells, and macrophages at sites of infection and inflammation, providing both direct antimicrobial activity and immunomodulatory signaling.

⚡ Quickstart Highlights

Reconstitution

2.0 mL BAC water → 2.5 mg/mL

Per-Dose Range

100–500 mcg per injection

1 U-100 Unit =

25 mcg

Frequency

Once daily or every other day

Dosing & Reconstitution Guide

Route: Subcutaneous | Frequency: Once daily or every other day

Phase	Daily Dose	U-100 Units	Volume	Notes
Conservative	100–200 mcg	4–8 units	0.04–0.08 mL	Starting dose; assess tolerance
Standard	300–400 mcg	12–16 units	0.12–0.16 mL	Typical research range
Full protocol	500 mcg	20 units	0.20 mL	Upper studied range

LL-37 can cause injection-site irritation at higher concentrations due to its cationic amphipathic structure. Diluting to a lower concentration (adding more BAC water) or rotating sites frequently minimizes this. Some protocols use subcutaneous, while others use intranasal for respiratory tract applications.

Reconstitution Steps

Draw 2.0 mL bacteriostatic water into a sterile syringe.
Inject slowly down the inside glass wall of the vial; avoid foaming.
Gently swirl until dissolved. Do not shake.
Label with reconstitution date. Refrigerate at 2–8°C; use within 28 days.

Supplies Planning

Item	8 Weeks (300 mcg/day)	12 Weeks
LL-37 vials (5 mg each)	4 vials	6 vials
Insulin syringes (30–50 unit)	56	84
Bacteriostatic water (10 mL)	2 × 10 mL	3 × 10 mL
Alcohol swabs	2 × 100-pack	2 × 100-pack

Mechanism of Action

LL-37 is generated by neutrophil granule serine protease cleavage of the hCAP18 preprotein (encoded by the CAMP gene). Its 37-amino acid sequence adopts an amphipathic alpha-helical structure that directly disrupts bacterial cell membranes through electrostatic interaction with negatively charged lipopolysaccharides, creating pores and causing osmotic lysis. Beyond direct antimicrobial activity against gram-positive and gram-negative bacteria, fungi, and some viruses, LL-37 has broad immunomodulatory functions: it chemoattracts monocytes, mast cells, and T cells; modulates TLR signaling to prevent excessive inflammation; promotes wound healing through keratinocyte migration; and has demonstrated angiogenic properties through VEGFR1/2 activation.

Research Findings & Safety Profile

Only human cathelicidin AMP — found at infection and wound sites; produced by innate immune cells.
Direct broad-spectrum antimicrobial activity: disrupts membranes of bacteria, fungi, some enveloped viruses.
Immunomodulatory: chemoattracts monocytes and T cells; modulates toll-like receptor (TLR) signaling.
Wound healing research: promotes keratinocyte migration, angiogenesis, and re-epithelialization in models.
Injection-site reactions (irritation, redness) are the most commonly reported adverse effect — lower concentration or alternate routes reduce this.
Research is predominantly preclinical and in vitro; limited human pharmacokinetic data available.

Storage

State	Temperature	Duration	Notes
Lyophilized	−20°C (−4°F)	Up to 24 months	Dry, dark conditions
Reconstituted	2–8°C (35–46°F)	Up to 28 days	Avoid freeze-thaw; protect from light

⚠ Research Use Only: LL-37 is an investigational compound. Injection-site irritation is the primary adverse effect — dilute to lower concentrations if this occurs. Research base is primarily preclinical.

References

Zanetti M. 'Cathelicidins, multifunctional peptides of the innate immunity' — J Leukoc Biol, 2004 View source ↗

Koczulla R et al. 'An angiogenic role for the human peptide antibiotic LL-37/hCAP-18' — J Clin Invest, 2003 View source ↗

Heilborn JD et al. 'The cathelicidin anti-microbial peptide LL-37 is involved in re-epithelialization of human skin wounds' — J Invest Dermatol, 2003 View source ↗