LL-37 calculator
A human antimicrobial peptide involved in immune defense. Studied for infection and wound healing; complex immune effects, no approved use.
Also known as: Cathelicidin, Human cathelicidin antimicrobial peptide
FDA status — not an approved drug Not FDA-approved for any use. LL-37 is a research peptide and is not reviewed by FDA for safety, effectiveness, or quality.
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What LL-37 is
LL-37 is the only human cathelicidin antimicrobial peptide, a natural part of the innate immune system. It directly kills a broad range of pathogens and also modulates immune responses. It is studied for infection and wound healing, but its immune effects are complex and context-dependent, and it has no approved use.
Research depth: 2/5 Well-characterized as a human antimicrobial peptide; therapeutic use complicated by complex immune effects. Human trials: Preclinical + observational. This measures how much has been studied — counting animal and laboratory work — not whether it works for you.
How LL-37 works
It disrupts microbial cell membranes, killing bacteria, fungi, and some viruses directly. It also acts on immune cells, where it can be both pro- and anti-inflammatory depending on context — promoting wound healing in some settings while contributing to inflammation in conditions like psoriasis in others. This duality complicates therapeutic use.
LL-37 side effects
Commonly reported
- Injection-site reactions
- Immune and inflammatory effects are complex and context-dependent
- No systematic human safety data
Serious — seek medical care
- Complex immune modulation — can be pro-inflammatory in some conditions
- Unknown long-term safety
- Unregulated products carry purity and sterility risks
This list is not exhaustive. Report anything unexpected to the clinician who prescribed it. If you have severe abdominal pain, trouble breathing, or signs of an allergic reaction, seek care the same day. See also our guide to peptide side effects by class.
A worked example
A 5 mg vial reconstituted with 2 mL of bacteriostatic water gives 2.5 mg/mL. A 250 mcg dose is then 0.1 mL — about 10 units on a 100-unit insulin syringe, giving roughly 20 doses per vial before accounting for residual volume left in the vial and syringe.
Prefer paper? Download the printable LL-37 dosing chart (PDF) — every vial size and water volume in syringe units, with the same review byline as this page. All charts →
Commonly cited dose range
Figures circulating for LL-37 run from 100 mcg to 500 mcg. No established dosing exists — LL-37 is a research peptide. Figures shown are supplier reference points in micrograms. There is no approved or established dose.
Read this as reference information, not instruction. These numbers describe what is commonly discussed, not what is right for any individual. Dose, frequency, and whether to use LL-37 at all are decisions for a licensed clinician who knows your history.
Common questions
What does LL-37 do?
LL-37 is the body's own antimicrobial peptide, part of the innate immune system. It kills bacteria, viruses, and fungi directly and also modulates immune responses. It is studied for infection and wound healing but has complex, sometimes pro-inflammatory effects.
Is LL-37 approved?
No. LL-37 is a research peptide with no approved human use. Its immune effects are complex and not fully characterized.