Library/For Recovery/LL-37

RUO · Research Use OnlyAntimicrobialFor RecoveryImmune+2 more

LL-37

The only human cathelicidin. We read all 60 studies. The protocol is below.

Updated 03 May 2026Read 12 minEvidence ●●○○○Citations 60

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Free — puts LL-37 on your decision board.

The LL-37 Report · $19

Everything you need to start: dose, sourcing, safety, our verdict.

One purchase · yours forever

Built from 60 cited studies.

Status

Research-only

Class

Antimicrobial

Evidence

2/ 5●●○○○

Randomized human trials

$19 ↓

Phase 3 completed

$19 ↓

Animal / in-vitro studies

$19 ↓

Read this if

you're in the chronic-Lyme / Bartonella / Babesia treatment community and your LLMD mentioned it
you've been diagnosed with CIRS or mold illness on a Shoemaker-adjacent protocol
you have biofilm-implicated chronic sinusitis or UTI and you've worked with an integrative MD on it
you're buying LL-37 partly because a contested diagnosis (Lyme, CIRS, mold/biofilm) is the framing — contested doesn't mean disproven, but it changes the risk math. Without diagnostic certainty there's no objective anchor for dose, duration, or stop criteria, so the experiment is harder to call won or lost. Keep that in front of you, not under it

Skip this if

you have rosacea, psoriasis, or any lupus-spectrum diagnosis — LL-37 is implicated in those flares
**you're on antibiotics or immunosuppressants right now.** LL-37 is itself an antimicrobial peptide — synergistic with abx (could amplify both effect and toxicity, including the GI/nephro/oto profile of whatever you're already on); opposed to immunosuppressants (the anti-inflammatory aim of the suppressant defeats the host-defense-amplification aim of LL-37). Don't run it concurrent without the prescriber driving that decision
you want phase 3 data — there is none for systemic use
you're shopping for general "immune support" without a specific infection diagnosis

The 4 ways you can buy LL-37

No FDA-approved LL-37 exists.

Compounded 503A

✓

$140–$300/mo

Some compounders carry; legitimacy depends on whether prescriber documents an indication.

RUO (research-only)

✓

Sold 'for research only'

$45–$120/mo

LL-37 is long (37 residues), synthesis quality varies — sub-90% purity is common.

Gray market

✓

Unregulated overseas import

~$6/mo (amortized — one box covers many months)

Crypto/Wise pay, no published COA; synthesis-difficulty of the 37-residue parent means identity-fa…

Click any lane for the full Sourcing breakdown. Prices and lane availability vary by molecule — this is the per-peptide snapshot, not a generic table.

First 90 days · LL-37

What we'd actually do

Weeks 1–2

Nothing perceptible. The healing-acceleration effect — if it's going to work — isn't a week-one signal. If you 'feel something' immediately, that's expectation, not the peptide.

Weeks 4–8

Subtle improvement on the target injury if it's going to work. Range of motion, less morning stiffness, less acute pain on load.

Week 12 — decide

Honest decision point. Either the injury is materially better than the no-peptide trajectory would have been, or it isn't. The clinical literature in humans is thin enough that your n=1 trial IS the evidence base.

Quit if

Any unusual symptoms — especially relevant if you have a personal or family cancer history (angiogenesis mechanism for BPC-157, TB-500).
12 weeks with no perceived improvement vs the no-peptide trajectory.
New pain or symptoms at injection site that don't resolve in 48 hours.

Identity

What it is.

LL-37 is the only cathelicidin antimicrobial produced by the human body. It's part of the innate immune system — the first-line defense your skin, lungs, and gut use to kill bacteria, viruses, and fungi before the adaptive immune system shows up.

The "LL" refers to two leucines at the N-terminus; "37" is the amino-acid length. It's released from a precursor protein (hCAP-18) by neutrophils and epithelial cells during infection or injury. Vitamin D regulates its expression, which is part of why low vitamin D correlates with higher infection risk.

Synthetic LL-37 is sold strictly as a research chemical (RUO) in the US. It's used off-label for chronic biofilm infections, some skin conditions, and post-Lyme protocols. It is not FDA approved for any indication and the human evidence base is thin.

TL;DR

TL;DR. 30-second version.

The compressed verdict — what LL-37 actually is, what the human evidence shows, and the watch-for in three bullets. Locked.

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Mechanism

Mechanism.

Mechanism · in the LL-37 report

How the molecule actually works — receptor profile, downstream signaling, what to expect mechanistically.

Get the report · $19 ↓

Evidence

Evidence. What we actually know in humans.

Evidence · in the LL-37 report

The trial breakdown — phase, n, primary endpoint, who funded, what hit, what didn't.

Get the report · $19 ↓

Human-Evidence Factbox

Randomized human trials

$19 ↓

Phase 3 completed

$19 ↓

Animal / in-vitro studies

$19 ↓

Mechanism

$19 ↓

Implicated in autoimmune flares

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Concurrent antibiotics

$19 ↓

Concurrent immunosuppressants

$19 ↓

Diagnostic anchor (Lyme/CIRS/biofilm)

$19 ↓

Years of off-label use

$19 ↓

Dose

Dose. The actual protocol.

Dose · in the LL-37 report

The specific protocol — dose, titration schedule, cycle pattern, frequency, route.

We read 60 studies to write this report.

Get the report · $19 ↓

Sourcing

Sourcing. Where the cohort actually buys.

Sourcing · in the LL-37 report

Sourcing breakdown — vendor methodology, red flags, our published test results, COA checklist.

We read 60 studies to write this report.

Get the report · $19 ↓

Safety

Safety. Side effects.

Safety · in the LL-37 report

The watch-for list — contraindications, drug interactions, monitoring labs, when to stop.

Get the report · $19 ↓

Editorial Position

Editorial position.

Editorial Position · in the LL-37 report

Our editorial position — explicit yes / no / depends, with the reasoning behind it.

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Citations

Citations.

+Show all 60 citations

The LL-37 Report · $19

Everything you need to start.

Dose, sourcing, safety, our verdict. One purchase. Yours forever.

Built from 60 cited studies.

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