LL-37 — Literature-Reported Ranges & Study Protocols

Read this first

Every figure on this page is a range reported in published literature or in a publicly documented study protocol. It is a record of what researchers used, not a recommendation, a therapeutic protocol, or advice. Peptide Intel Hub is an independent publication, sells nothing, and describes these compounds as in-vitro research reagents only.

Compound at a glance

Class: 37-amino-acid cathelicidin antimicrobial peptide
Reported half-life: Short in serum; activity is measured locally in most designs
Routes used in the literature: Topical and intralesional in human wound studies; systemic only in animal models
Also written as: Cathelicidin LL-37

What the published studies reported

Each row below describes one body of work. The model and population are part of the figure — a rodent per-kilogram quantity and a human trial quantity are not comparable.

Human venous leg ulcer phase 2

Reported quantity: 0.5, 1.6 and 3.2 mg/mL topical formulations
Frequency: Twice weekly application
Study duration: 4 weeks

The lower concentrations outperformed the highest arm on wound-area reduction.

In-vitro antimicrobial assays

Reported quantity: MIC typically 1–32 µg/mL depending on organism
Frequency: Single exposure
Study duration: 18–24 hours

Activity drops sharply in physiological salt and serum — a critical caveat for these figures.

Rodent infection and wound models

Reported quantity: 0.1–5 mg/kg systemically; 10–100 µg per wound topically
Frequency: Once daily
Study duration: 3–14 days

Cytotoxicity at higher concentrations is consistently reported.

Dosage chart

These figures match the published chart for this compound on peptidedosages.com, including the reconstitution volume, resulting concentration, insulin-syringe units and the staged schedule. Educational reference only — not instructions, and not medical advice.

LL-37 · 5 mg Vial

LL-37 is dosed at 50 mcg–400 mcg daily via subcutaneous injection in educational protocols. A 5 mg vial reconstituted with bacteriostatic water yields about 1.67 mg/mL. This information is for research and educational use only.

Reconstitute: Add 3.0 mL bacteriostatic water → ~ 1.67 mg/mL concentration.
Typical daily range: 100–400 µg once daily (gradual titration).
Easy measuring: At 1.67 mg/mL, 1 unit = 0.01 mL ≈ 16.7 µg on a U-100 insulin syringe.
Storage: Lyophilized: freeze at −20 °C (−4 °F); after reconstitution, refrigerate at 2–8 °C (35.6–46.4 °F) for up to 4 weeks; avoid freeze–thaw cycles.

Standard / Gradual Approach (3 mL = ~1.67 mg/mL)

Week	Daily Dose (µg)	Units (per injection) (mL)
Week 1	50 µg	3 units (0.03 mL)
Week 2	100 µg	6 units (0.06 mL)
Week 3	150 µg	9 units (0.09 mL)
Week 4	200 µg	12 units (0.12 mL)
Week 5	250 µg	15 units (0.15 mL)
Week 6	300 µg	18 units (0.18 mL)
Week 7	350 µg	21 units (0.21 mL)
Week 8	400 µg	24 units (0.24 mL)

Source chart on peptidedosages.com

Mixed with 3 ml of bacteriostatic water

The same arithmetic for every vial size LL-37 is supplied in, using a fixed 3 ml of bacteriostatic water. One unit on a U-100 insulin syringe is 0.01 ml, so the unit column below is simply the volume that carries the reported amount. Educational arithmetic only — not instructions, and not medical advice.

LL-37 · 3 ml bacteriostatic water

Vial size	Concentration	Per 1 unit	100 mcg =	400 mcg =
5 mg	1.67 mg/ml	17 mcg	6.0 units	24 units

Unit columns use the range reported for this compound (100 mcg–400 mcg). Only the vial sizes this compound is actually supplied in are shown, and every figure assumes exactly 3 ml of bacteriostatic water. For any other volume, use the reconstitution calculator.

Reconstitution maths

A 5 mg vial in 5 mL of sterile water gives 1 mg/mL. LL-37 adsorbs strongly to plastic, so low-binding tubes are standard practice in the literature.

Open the reconstitution calculator

How to read these figures

Concentration-dependent cytotoxicity to host cells is a documented property, not a contaminant effect.
Salt and serum sensitivity means in-vitro MIC values overstate activity in tissue.
LL-37 is implicated in psoriasis and rosacea pathology — the immunology literature is not one-directional.

Sources and citations

These are the published records the figures on this page are drawn from. Each one describes what researchers administered, in which model or population, and over what period. Quantities reported in a study are specific to that study's design and are not transferable guidance.

[1]
Treatment with LL-37 is safe and effective in enhancing healing of hard-to-heal venous leg ulcers: a randomized, placebo-controlled clinical trial
Grönberg A, Mahlapuu M, Ståhle M, Whately-Smith C, Rollman O. · Wound Repair Regen · 2014 · DOI 10.1111/wrr.12211
First-in-man dose-response trial applying topical synthetic LL-37 peptide (at concentrations from 0.5 to 1.6 mg/mL of gel) to hard-to-heal venous leg ulcers over multiple weeks.
View the record
[2]
Evaluation of LL-37 in healing of hard-to-heal venous leg ulcers: A multicentric prospective randomized placebo-controlled clinical trial
Mahlapuu M, Sidorowicz A, Mikosinski J, et al. · Wound Repair Regen · 2021 · DOI (see liu.diva-portal.org)
Multicenter phase IIb trial administering topical LL-37 gel at defined doses twice weekly to venous leg ulcer patients over 12 weeks.
View the record

Search the databases yourself

Read the LL-37 research brief

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All research protocols

Peptide Intel Hub is an independent publication and has no affiliation, ownership or commercial relationship with the suppliers listed. We sell nothing and take no payments — links are editorial references only.