PeptideCalculations
human antimicrobial peptide

LL-37 dosage

LL-37 is the active fragment of human cathelicidin, an antimicrobial peptide your own cells make. The only human trial is topical: 0.5 to 1.6 mg/mL applied twice a week to leg ulcers sped healing, and 3.2 mg/mL did not. No human has been dosed by injection in a study. Community use is 100 to 200 mcg subcutaneously, once a day, 5 days a week, for 2 to 4 weeks. It is a potent peptide, so people run it short.

By the Peptide Calculations editors · Updated 2026-10-19 · Studied for chronic wound healing (topical trial), biofilms and infection in the lab, immune signaling

Dose
0.5 mg/mL to 1.6 mg/mL topical, twice weekly
per application · Human trial
How often
once daily
any time; near a wound site for local use
How long
2 to 4 weeks on
2 weeks off
Route
subcutaneous
community or topical on wounds trial

1Dose ranges by source

RangePerBasisNote
0.5 mg/mL to 1.6 mg/mL topical, twice weeklyapplicationHuman trial
clinical trial (Gronberg et al. 2014, Wound Repair Regen, 34 patients with venous leg ulcers, randomized, placebo-controlled, 4 weeks)
healing rate about 6-fold higher at 0.5 mg/mL; 3.2 mg/mL no better than placebo; no safety concerns
100 mcg to 200 mcg per injectioninjectionCommonly reported
commonly reported
once daily, 5 days a week, 2 to 4 weeks; no established human subcutaneous dose

2Dose to units chart

5 mg vial + 5 mL bacteriostatic water = 1 mg/mL, so each unit on a U-100 insulin syringe holds 10 mcg.

DoseDraw (mL)UnitsDoses in vial
1 mcg0.00050.0510000
1 mcg0.0010.15000
2 mcg0.00160.163125
2 mcg0.0020.22500
Open in the LL-37 calculatorFull 5 mg + 5 mL table

5 mg + 5 mL = 1 mg/mL, so 100 mcg = 0.1 mL = 10 units and 200 mcg = 20 units. For a topical mix in the trial range, 5 mg in 5 mL is already 1 mg/mL.

3Commonly stacked with

KPV · 200 mcg to 500 mcg per injection

4Side effects

injection site pain and redness (it is cytotoxic at high concentration)flu-like fatigue (reported)headache (reported)
Before you start. Human injection dosing is not established; the one human trial was topical and the highest topical dose stopped working, which argues against pushing dose. LL-37 is pro-inflammatory in some settings and is elevated in psoriasis and rosacea, so people with those conditions should be careful. Not medical advice. Talk to a clinician and start low.

Storage: lyophilized: freezer; reconstituted: fridge, use within 2 to 4 weeks (commonly reported); it degrades faster than most peptides

5LL-37 dosage questions

LL-37 peptide dosage?

No human injection dose exists. Community use is 100 to 200 mcg subcutaneously once a day, 5 days a week, for 2 to 4 weeks. The human trial used it on the skin at 0.5 to 1.6 mg/mL twice a week, and the higher 3.2 mg/mL dose did worse than the low ones.

How many units of LL-37 is 100 mcg?

With 5 mg in 5 mL (1 mg/mL) 100 mcg is 10 units. With 2 mL of water it is 4 units, which is hard to read, so use the full 5 mL.

Can you inject LL-37 near a wound?

People do, subcutaneously a few centimeters from the site, copying the topical trial logic. The trial itself applied it to the wound surface. Do not inject into infected or broken skin.

How long should an LL-37 cycle be?

2 to 4 weeks, then at least 2 weeks off. The trial ran 4 weeks. Longer continuous use has no data and the peptide can irritate tissue.

6Sources

  1. Gronberg A et al., Wound Repair Regen 2014, Treatment with LL-37 in hard-to-heal venous leg ulcers: a randomized, placebo-controlled clinical trial (PubMed 25041740)
  2. Peptide Protocol Wiki, LL-37 dosing (community subcutaneous ranges)

Educational summary of published labels, trials and commonly reported use. Not medical advice.

Brands we recommend for LL-37Independent. No affiliation with any brand, no affiliate links, no referral codes, no paid placements.
  1. 1Licensed Peptides two accredited labs on every lot, certificates public, card and Apple Pay checkout
  2. 2Core Peptides long track record, public certificates, wide catalog
  3. 3Ascension Peptides public third-party testing, clear pricing