Larazotide vs LL-37
A neutral, side-by-side comparison of two healing & recovery peptides — their mechanisms, dosing ranges, administration routes, side effects, and research evidence. For research and educational purposes only.
Larazotide
Larazotide (AT-1001) is a synthetic octapeptide that acts as a tight junction regulator — it competitively blocks zonulin, the primary physiological driver of intestinal permeability ('leaky gut'). It is one of the few compounds studied in human clinical trials specifically for tight junction dysfunction, with Phase 2 data in celiac disease demonstrating reduced intestinal permeability and symptom improvement even in the presence of ongoing gluten exposure.
Full profileLL-37
LL-37 is the only human cathelicidin — a host defense peptide produced by neutrophils, epithelial cells, and macrophages in response to infection and inflammation. It functions simultaneously as a broad-spectrum antimicrobial agent and an immune-modulatory signaling molecule. Research interest has expanded dramatically since COVID-19 studies linked low LL-37 levels to severe outcomes, and gut health research identified it as a key regulator of intestinal barrier integrity.
Full profile| Larazotide | LL-37 | |
|---|---|---|
| Category | Healing & Recovery | Healing & Recovery |
| Also known as | Larazotide acetate, AT-1001, INN-202 | Cathelicidin LL-37, hCAP-18 C-terminal fragment, CRAMP (murine equivalent) |
| Evidence | FDA-approved | Research-stage |
| Dosing range | 0.25mg–1mg mg, 3x daily (before meals) | 100mcg–500mcg mcg, Daily or 3–5x weekly |
| Administration | Oral (capsule), Subcutaneous injection (research use) | Subcutaneous injection, Intranasal (for respiratory applications), Topical (wound care) |
| Key side effects | Headache (most commonly reported adverse event in trials), Nausea (mild), Generally well-tolerated — adverse event rate similar to placebo in clinical trials | Injection site redness and irritation (common — pro-inflammatory at injection site), Transient flu-like symptoms (immune activation), Local induration, High doses may be cytotoxic — dose-response curve is non-linear |
| Cited sources | 3 references | 3 references |
Key differences
- Evidence level differs: Larazotide is fda-approved, while LL-37 is research-stage.
- Administration: Larazotide — Oral (capsule), Subcutaneous injection (research use); LL-37 — Subcutaneous injection, Intranasal (for respiratory applications), Topical (wound care).
- Dosing units differ: Larazotide is dosed in mg, LL-37 in mcg — they operate at different scales.
- Frequency: Larazotide is typically 3x daily (before meals); LL-37 is Daily or 3–5x weekly.
How each works
Larazotide
Zonulin upregulation disrupts the tight junction proteins occludin and claudin, allowing paracellular passage of antigens, LPS, and inflammatory triggers into systemic circulation. Larazotide acts as a tight junction agonist by competitively displacing zonulin from its receptor and directly stabilizing tight junction complexes. The Phase 2b CeD trial (N=342) showed larazotide reduced the ratio of lactulose/mannitol (L/M ratio, standard intestinal permeability marker) and improved GI symptom scores versus placebo in actively-challenged celiac patients.
LL-37
LL-37 exerts antimicrobial activity by disrupting bacterial membranes via electrostatic interaction with negatively charged lipopolysaccharide — effective against gram-positive and gram-negative bacteria, fungi, and enveloped viruses including SARS-CoV-2 in vitro. Beyond direct antimicrobial action, LL-37 modulates innate immunity through TLR4 signaling, promotes wound healing via EGFR and FPRL1 receptor activation, and has demonstrated anti-biofilm activity against P. aeruginosa and S. aureus. Vitamin D is the primary driver of endogenous LL-37 production.
This comparison aggregates public research and structured profile data for informational purposes only. It is not medical advice and does not recommend either compound for human use. Consult a qualified healthcare provider before considering any peptide.