Larazotide.
Larazotide (larazotide acetate, research code AT-1001) is a synthetic eight-amino-acid peptide investigated as an oral, gut-restricted therapy for celiac disease.
Larazotide (larazotide acetate, research code AT-1001) is a synthetic eight-amino-acid peptide investigated as an oral, gut-restricted therapy for celiac disease. Larazotide is in human trials, and PepCue grades its published evidence C tier (63/100). Also known as AT-1001 · larazotide acetate. This is a research reference, not medical or dosing advice.
What it is
Larazotide (larazotide acetate, research code AT-1001) is a synthetic eight-amino-acid peptide investigated as an oral, gut-restricted therapy for celiac disease. It was designed to act locally in the small intestine rather than being absorbed systemically. The concept was to add a first non-dietary treatment for patients who still have symptoms despite a gluten-free diet. It advanced through Phase 2 and into Phase 3 development but is not approved by the FDA or any major regulator. It is categorized under healing because its target is intestinal barrier repair and integrity.
How it works
Larazotide is a tight-junction regulator, often described as a zonulin antagonist. In celiac disease, gluten exposure is associated with increased release of zonulin and loosening of the tight junctions between intestinal epithelial cells, allowing gluten peptides to cross the barrier and drive immune activation. Larazotide is proposed to promote tight-junction assembly and reduce paracellular permeability (leaky gut), thereby limiting gluten peptide entry and downstream inflammation. It is intended to work in the gut lumen, which fits its minimal systemic absorption. The precise molecular target and the physiological role of zonulin itself remain areas of scientific debate.
Mechanism pathways
Controlling how much passes between intestinal cells rather than through them.
The intestinal lining is a single layer of epithelial cells that must absorb nutrients while excluding the enormous antigenic load of the gut contents. Two routes cross it. The transcellular route goes through cells and is tightly controlled by transporters. The paracellular route goes between adjacent cells and is governed by tight junctions, protein complexes built from claudins, occludin, and junctional adhesion molecules, anchored to the actin cytoskeleton through scaffolding proteins. Tight junctions are dynamic rather than fixed: their permeability is actively regulated, and myosin light chain kinase acting on the perijunctional actomyosin ring is one of the main levers. Zonulin is a protein proposed to be a physiological regulator of this permeability. In the model that motivates this pathway, exposure to gluten peptides in susceptible individuals triggers zonulin release, tight junctions loosen, and gluten fragments cross the barrier into the lamina propria where they drive the immune activation characteristic of celiac disease. Increased paracellular permeability is the popular concept usually called leaky gut. The compound in this group is a tight-junction regulator, commonly described as a zonulin antagonist. Rather than blocking the immune response, it is proposed to promote tight-junction assembly and reduce paracellular permeability, limiting entry of the triggering peptides in the first place. This upstream position is what distinguishes it from anti-inflammatory or enzyme-based approaches. Importantly, it is designed to act from the gut lumen rather than systemically, which is consistent with its minimal absorption. That is an advantage for safety and a constraint on what it could ever treat. Several honest qualifications belong here. The precise molecular target has not been definitively identified, and the physiological role of zonulin itself, including whether the protein commonly measured in commercial tests is the one described in the original work, remains genuinely debated in the literature. Leaky gut as a popular concept extends far beyond what the underlying science supports, and increased permeability has been described in various conditions without it being established as a cause rather than a consequence. This compound reached late-stage clinical testing in celiac disease and did not achieve approval. It is not an approved medicine, and no tight-junction regulator has been approved for any indication.
The evidence
Mid-stage data were encouraging but the definitive trial did not succeed. In a Phase 2b randomized, double-blind, placebo-controlled trial (Leffler et al., Gastroenterology, 2015; 342 patients with persistent symptoms despite a gluten-free diet), low-dose larazotide reduced patient-reported symptoms versus placebo, with the lowest dose showing the clearest signal. On the strength of such results the program advanced to a large Phase 3 trial (CeD-2001) run by 9 Meters Biopharma. That Phase 3 study was halted after an interim analysis indicated it was unlikely to meet its primary endpoint, the change from baseline in celiac symptom severity, effectively ending the program. In short: positive Phase 2b data did not translate into a successful Phase 3 result, and larazotide is not an approved therapy. Several features of the earlier evidence look different in hindsight. The Phase 2b result was strongest at the lowest dose tested, without a conventional dose-response relationship, a pattern that is difficult to interpret mechanistically and that often does not reproduce. Primary endpoints across the program were patient-reported symptom scores rather than histology or objective mucosal healing, and symptom scores in celiac disease are noisy and prone to large placebo responses. Supporting biology exists outside these trials: larazotide acetate promoted recovery of ischemia-injured porcine jejunum through repair of tight junctions (PLoS One, 2021), and reviews of celiac pharmacotherapy place tight-junction regulation among several strategies that have been tried without yet producing an approved drug (European Journal of Pharmacology, 2021). The comparison that matters is with existing management. A strict lifelong gluten-free diet remains the only established treatment for celiac disease, supported by decades of clinical experience and by histologic and serologic recovery in patients who adhere to it. No drug has been approved as an adjunct or replacement. Larazotide reached the last stage of testing and failed there, so the honest summary is that the leading non-dietary candidate did not demonstrate benefit when tested at confirmatory scale.
The evidence, in brief
An oral, gut-restricted tight-junction regulator (AT-1001) developed for celiac patients with symptoms despite a gluten-free diet. A 342-patient phase-2b randomized trial reported a symptom benefit versus placebo, but the pivotal phase-3 CeD-2001 trial was halted at interim analysis for likely futility on its primary endpoint, effectively ending the program. It is not approved by the FDA or EMA, and this is a case where promising mid-stage data did not survive a definitive trial.
- Leffler DA et al.: Larazotide acetate for persistent symptoms of celiac disease despite a gluten-free dietGastroenterology, 2015 (PMID 25683116)
- PubMed search: larazotide celiac diseasePubMed / NCBI
Evidence maturity
An evidence-only reading: approval status, human vs preclinical data, mechanism and safety. Popularity never raises it. Research file #036
Some human signal atop preclinical work; gaps remain.
Studied in human clinical trials; evidence is meaningful.
Claim receipts
Popular claims about Larazotide, checked against the state of the evidence. The verdict describes evidence maturity, never an invented study result.
Tight-junction repair and reduced permeability are shown in cell and animal work; the human trials measured symptoms rather than barrier or mucosal outcomes.
A phase 2b randomized placebo-controlled trial reported a symptom benefit, but the confirmatory phase 3 trial was halted at interim analysis for likely futility.
It was studied only as an adjunct for persistent symptoms despite a gluten-free diet, and the diet remains the only established management.
It is not approved by the FDA or EMA, and development ended after the pivotal trial was discontinued.
Trial exposure was short and in selected participants, no post-marketing surveillance exists, and material sold outside a trial has no verified identity or manufacturing oversight.
Safety profile
Across trials larazotide was generally well tolerated, consistent with a peptide that acts locally in the gut and is minimally absorbed. Reported adverse events were typically mild and gastrointestinal, such as abdominal discomfort, nausea, or headache, and were often similar between drug and placebo groups. Minimal systemic absorption limits the plausibility of effects outside the intestinal lumen, and no distinctive organ toxicity emerged as a program-stopping signal; the Phase 3 trial was discontinued for likely futility on efficacy, not for safety. Because development stopped before approval, there is no long-term real-world safety dataset in a broad treated population. Clinical trial exposure was limited in duration and confined to selected participants who met entry criteria, so effects of use over years, in children, in pregnancy, in older patients with comorbidities, or alongside common medications were never characterized. There is no post-marketing pharmacovigilance stream because there is no marketed product, and no regulator has reviewed a complete safety dossier. Anything sold as larazotide outside a clinical trial carries the separate risks of unapproved supply: no verified identity or purity, no batch testing, no good manufacturing practice oversight, and no adverse-event reporting. There is also an indirect risk specific to celiac disease, since any product presented as protection against gluten exposure could encourage relaxation of the gluten-free diet, which remains the only established management and the only intervention shown to allow mucosal recovery. This entry is educational only and is not a recommendation to obtain or use the compound, which is not an approved medicine.
Compound notes
- Larazotide (larazotide acetate, research code AT-1001) is a synthetic eight-amino-acid peptide investigated as an oral, gut-restricted therapy for celiac disease.
- It is a tight-junction regulator, often described as a zonulin antagonist: it is proposed to promote tight-junction assembly and reduce paracellular permeability, limiting entry of gluten peptides across the intestinal barrier.
- It was designed to act locally in the gut lumen with minimal systemic absorption, aimed at patients with persistent symptoms despite a gluten-free diet.
- A Phase 2b randomized, placebo-controlled trial in 342 patients showed a patient-reported symptom benefit, but the pivotal Phase 3 trial (CeD-2001, 9 Meters Biopharma) was halted after interim analysis for likely futility, effectively ending the program.
The gluten-free diet removes the trigger. Larazotide aimed instead to tighten the barrier so residual gluten peptides cause less immune activation. That approach did not clear its pivotal trial.
- Not approved by the FDA or EMA; it remains investigational with a failed pivotal trial, and anything sold as larazotide outside a clinical trial is not an approved drug.
- It was generally well tolerated in trials, with mild gastrointestinal events often similar between drug and placebo, consistent with a minimally absorbed gut-restricted peptide.
- Because development stopped before approval, there is no long-term real-world safety dataset.
Regulatory status
Larazotide is investigational and is not approved by the FDA or EMA for celiac disease or any other indication. It reached Phase 3, but the pivotal CeD-2001 trial was discontinued for likely futility on its primary endpoint. Any product sold as larazotide outside of a clinical trial is not an approved drug.
Investigational, currently in registered human clinical trials.
By the numbers
- 01Oral, gut-restricted 8-amino-acid peptide (AT-1001) studied for celiac disease.
- 02Acts as a tight-junction regulator / zonulin antagonist to reduce intestinal permeability.
- 03Aimed at patients with persistent symptoms despite a gluten-free diet.
- 04Phase 2b trial (Leffler 2015, n=342) showed a symptom benefit at the lowest dose versus placebo.
- 05Phase 3 CeD-2001 (9 Meters Biopharma) was halted after interim analysis for likely futility.
- 06Not FDA- or EMA-approved; remains investigational with a failed pivotal trial.
Larazotide: research formats
Choose the format you are researching to see route-specific notes.
Designed to act locally in the small intestine rather than be absorbed. Investigational, never approved.
Larazotide acetate is an oral, gut-restricted eight-amino-acid peptide investigated for celiac disease. Its whole design premise is the opposite of most peptides on this site: it is meant to stay in the intestinal lumen and act on tight junctions there rather than reach the bloodstream. It reached Phase 3, but the pivotal CeD-2001 trial was halted at interim analysis for likely futility, so no approved product or labeled regimen exists.
Because the target is the intestinal barrier itself, systemic absorption is not the goal. That makes injectable formats irrelevant to how this compound was studied.
Larazotide is not approved by the FDA or EMA. Anything sold under that name outside a clinical trial is not an approved drug.
Sources
Every factual claim above resolves to a real, published source.
- Larazotide acetate for persistent symptoms of celiac disease despite a gluten-free diet: a randomized controlled trialLeffler DA, et al. Gastroenterology, 2015 (PMID 25683116)
- PubMed: larazotide celiac diseasePubMed literature search (includes Phase 2/3 program reports)
- Larazotide acetate induces recovery of ischemia-injured porcine jejunum via repair of tight junctionsPLoS One, 2021 (PMID 33886649); preclinical tight-junction repair
- Current pharmacological approaches and potential future therapies for Celiac diseaseEur J Pharmacol, 2021 (PMID 34418405); places larazotide among tried strategies
- ClinicalTrials.gov: larazotide acetate celiac disease trialsRegistry search including the discontinued Phase 3 program
Cite this page
PepCue. “Larazotide: the evidence.” PepCue, reviewed June 1, 2026. https://www.pepcue.app/p/larazotide.
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