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Larazotide (AT-1001, Larazotide Acetate)

D

lead outcome

Celiac disease (the lead, best-studied use)

grades vary by outcome ↓

Peptide

also called — Larazotide · larazotide acetate · AT-1001 · INN-202

intestinal barrier / tight-junction regulationceliac disease (adjunct, investigational)"leaky gut" (the concept it actually targets)gut health

The "leaky gut" drug that got furthest — and still failed Phase 3. Larazotide is unusual in this register: a first-in-class, FDA Fast-Tracked, Phase 3-stage pharmaceutical — the most clinically advanced non-dietary celiac-disease drug ever — not a typical gray-market peptide. Three threads: (1) its mechanism is genuinely novel — it's the first drug to target intestinal permeability ("leaky gut") by tightening the junctions between gut cells; (2) it reached Phase 3 with positive Phase 2 data and a real pipeline; (3) in June 2022 that Phase 3 was discontinued for futility — a major setback for the whole zonulin/"leaky gut" pharmacologic hypothesis. The most-developed leaky-gut drug in history couldn't beat placebo — a sobering fact for the supplement hype around the same concept.

In brief

Larazotide (AT-1001) is a synthetic octapeptide and a first-in-class "tight-junction regulator" — the first drug ever aimed at intestinal permeability, the "leaky gut" concept. Taken orally and acting only inside the gut, it works as a zonulin antagonist: in celiac disease, gluten makes the junctions between intestinal cells spring open (via zonulin), letting gliadin through to trigger the immune attack — and larazotide is designed to hold those junctions shut. It's genuinely notable for how far it got: developed across three companies (Alba → Innovate → 9 Meters), it became the most clinically advanced non-dietary celiac drug, the only Phase 3-stage one, with FDA Fast Track and positive Phase 2b data. But in June 2022 its pivotal Phase 3 (CeDLara) was stopped for futility — an interim analysis showed it couldn't feasibly beat placebo — a major blow to the whole zonulin/"leaky gut" drug hypothesis. As of 2026 it's approved for nothing. The honest, and broadly important, takeaway: the most rigorously developed "leaky gut" drug in history failed its decisive trial — which should temper the far larger, far less tested wellness-market hype around "leaky gut" supplements. A real drug, a real mechanism, a real (negative) answer.

Legal standing, by region

United States

Not approved

not approved for any indication (the Phase 3 celiac program failed in 2022). It had FDA Fast Track during development, but never reached approval. Investigational.

Evidence, by outcome

How we grade →

An honest grade per outcome — drawn from the evidence, not any catalogue. Hype and undemonstrated marketing claims grade low.

OutcomeEvidence base · effectGrade

Celiac disease (the lead, best-studied use)

The defining fact: reached Phase 3 and failed — couldn't feasibly beat placebo. Not "untested" — tested and negative at the pivotal stage

Positive Phase 2b (342 pts) → but Phase 3 CeDLara discontinued for futility (2022)

D

Tight-junction / permeability mechanism

The biology of tight-junction regulation is real and elegant; it didn't translate to a positive clinical endpoint

Well-characterized: zonulin antagonism; MLCK inhibition; rodent + porcine barrier-repair models

C

"Leaky gut" / general gut health (the gray-market pitch)

The broad wellness claim is not supported; even the targeted celiac trial failed

No approved indication; concept-level only

F

Adjacent indications (MIS-C, intestinal ischemia)

Exploratory; nothing established

Early/preclinical (porcine ischemia repair, pediatric research)

F

Safety

Generally well-tolerated in trials (a genuine plus — its problem was efficacy, not safety); long-term chronic-modulation effects unestablished

Extensive trial exposure; gut-restricted (minimal systemic absorption)

B

Disclosure

Vallydia sells its own cosmetic serums, and some ingredients graded here belong to the same categories as those products. Grades are drawn from the published evidence by the method we publish, and applied to our own ingredients on the same terms — our copper-peptide serum is graded no more kindly than the peptides it competes with. We disclose the interest so you can weigh it.

Trade names shown here (for example Matrixyl, Argireline, Syn-Ake) are the property of their respective owners and are used only to identify the ingredient under discussion. Their appearance implies no affiliation with, or endorsement by, the proprietor.

Evidence changes

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Identity

a synthetic single-chain octapeptide (8 amino acids) that is a first-in-class intestinal tight-junction regulator — the first drug ever to target intestinal permeability ("leaky gut") as a therapeutic mechanism. It's orally administered and "gut-restricted" (acts locally in the intestinal lumen, essentially not absorbed systemically), developed as an adjunct to the gluten-free diet for celiac disease. Structurally related to cholera's Zot toxin (which opens junctions); larazotide is designed to help close them.

Mechanism (as proposed)

the intestinal epithelium is sealed by tight junctions — protein complexes (claudins, occludin, ZO-1) that control what passes between cells (the paracellular route). In celiac disease, gliadin triggers zonulin release, which signals the tight junctions to disassemble, increasing permeability and letting gliadin reach the immune cells beneath — driving inflammation. Larazotide is a zonulin receptor antagonist that blocks this opening, promoting redistribution/reassembly of tight-junction proteins and actin filaments (partly via myosin-light-chain-kinase inhibition, which relaxes the actin tension that pulls junctions apart) — thereby restoring/maintaining barrier integrity. Being gut-restricted, it does this locally with minimal systemic exposure (a safety advantage). The mechanism is coherent and animal-validated — and yet the Phase 3 clinical endpoint wasn't met, the register's recurring reminder that a beautiful mechanism and even positive Phase 2 data don't guarantee pivotal success.

Chemical identifiers

Cross-reference identifiers for the authoritative external databases — not a recipe, and nothing about how to use it.

PubChem CID9810532

InChIKeyORFLZNAGUTZRLQ-ZMBVWFSWSA-N

SMILESCC(C)C[C@@H](C(=O)N[C@@H](C(C)C)C(=O)N[C@@H](CCC(=O)N)C(=O)N1CCC[C@H]1C(=O)NCC(=O)O)NC(=O)[C@H](C(C)C)NC(=O)CNC(=O)CN

ChEMBLCHEMBL2105646

DrugBankDB05645

via PubChem exact-name match (Larazotide) · high confidence

Sources — 4 cited

01Slifer ZM, Krishnan BR, Madan J, Blikslager AT. Larazotide acetate: a pharmacological peptide approach to tight junction regulation. Am J Physiol Gastrointest Liver Physiol. 2021 (mechanism; zonulin/MLCK).

02Phase 2b (Alba Therapeutics, 2014; 342 patients) — reduced symptoms; non-monotonic dose response.

03CeDLara Phase 3 (CeD-LA-3001, 525 patients): discontinued for futility, June 2022 (9 Meters Biopharma press release; BioSpace, BeyondCeliac coverage) — interim analysis, couldn't feasibly beat placebo.

04Fasano A, et al. Zonulin, a newly discovered modulator of intestinal permeability, and its expression in coeliac disease. Lancet. 2000 (the zonulin concept). Porcine ischemia tight-junction repair (2021). (No FDA approval as of 2026; celiac program halted.)

Updated 2026-07-13 (status: celiac Phase 3 failed 2022, no approved indication; watch only for revived development in adjacent barrier-disease indications)

Grades reflect the published evidence, not our interest. No dosing, reconstitution, or administration is published for research compounds — that restraint is deliberate.

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