Larazotide vs LL-37
Two peptides sold for gut/barrier health with genuinely different regulatory maturity — one that actually reached Phase 3 and failed, the other still entirely preclinical.
Larazotide
AT-1001
A tight-junction regulator with real celiac Phase 2 data — but its pivotal Phase 3 failed, and the supplement use runs far ahead of the evidence.
Full Larazotide evidence reviewLL-37
Cathelicidin
Genuine innate-immunity biology, but its therapeutic use is preclinical — and the same peptide is implicated in driving inflammatory disease.
Full LL-37 evidence reviewSide by side
| Larazotide | LL-37 | |
|---|---|---|
| Marketed for | Leaky gut, celiac disease | Infection, immunity, healing |
| Evidence grade | Clinical data | Preclinical / minimal |
| Family | Immune / metabolic | Immune / metabolic |
| Regulatory status | Investigational | Not FDA-approved |
| How it's obtained | Research-only | Research-only |
| Key human source | Leffler, Gastroenterology 2015 | Lande, Nature 2007 |
marks a row where the two differ. Evidence grades come from our evidence matrix, which grades each molecule on the human data for the use it is marketed for.
Our verdict
Larazotide got further than almost anything on this list: real Phase 2 celiac data, but its pivotal Phase 3 trial failed, and the leaky-gut supplement use runs well ahead of what even the positive early data showed. LL-37 has genuine innate-immunity biology and real mechanism, but its therapeutic use remains entirely preclinical — and the same peptide is also implicated in driving inflammatory disease, a double-edged detail marketing tends to skip.
Larazotide fits if
Celiac-adjacent gut-barrier function specifically is the interest, understanding the pivotal trial for that exact use failed.
LL-37 fits if
You're reading about innate-immunity peptide biology generally — there's no human trial behind any product sold under this name.
Where to get it
Where to get peptide therapy
Clinician-led telehealth services that prescribe compounded peptides. The specific peptides offered vary by provider — confirm Larazotide availability before ordering.
