Larazotide
Not FDA-approved
Also known as: Larazotide acetate, AT-1001, INN-202
Larazotide is a lab-made peptide of eight amino acids, taken by mouth, designed to keep the seals between gut-lining cells closed. In a celiac disease trial, only the lowest of three strengths eased symptoms, and a larger follow-up trial was stopped early. A small trial in children with a post-COVID inflammatory illness reported faster recovery.
How it works
- It targets tight junctions, the seals that join the cells lining the gut. In lab and animal studies, it appeared to keep these seals from opening.
- Its structure comes from a protein made by the cholera bacterium, one that opens these seals. Larazotide was designed to work against that target instead.
- It acts on the gut lining from inside the gut and is not absorbed into the bloodstream.
- It is described as blocking zonulin, a signal the body uses to loosen these seals.
- After COVID-19, researchers proposed that blocking zonulin might stop viral spike protein from leaking out of the gut into the blood.
Evidence
Celiac disease symptoms despite a gluten-free diet
In a 12-week trial of 342 adults, the lowest of three strengths eased symptoms compared with placebo; the two higher strengths did not. In a gluten-challenge trial of 184 adults, it did not improve the main gut-permeability measure. A larger phase 3 trial was stopped early in 2022 without confirming the benefit.
Post-COVID inflammatory illness in children (MIS-C)
In a placebo-controlled trial of 12 children, those given it had faster resolution of gut symptoms and faster clearance of spike protein. These results are as reported by the investigators. The trial was very small and ended early.
Caveats
- Why the higher strengths did no better than placebo in the celiac trial is unclear.
- It was tested as an add-on to a gluten-free diet, not a replacement for one.
- Side effects were similar to placebo in the celiac trials, and none were linked to it in the children's trial.
- A trial in long COVID finished in 2026, but its results have not been posted.
References
- Leffler DA, et al. Gastroenterology. 2015;148:1311-1319.e6.
- Kelly CP, et al. Aliment Pharmacol Ther. 2013;37:252-262.
- Paterson BM, et al. Aliment Pharmacol Ther. 2007;26:757-766.
- Yonker LM, et al. Sci Transl Med. 2025;17:eadu4284.
- ClinicalTrials.gov NCT03569007 (phase 3 trial in celiac disease, terminated 2022).
This page is for education only. It is not medical advice. Decisions about any treatment belong with a physician who knows your history.