Larazotide
A synthetic peptide that regulates intestinal tight junctions, in clinical trials for celiac disease and studied for leaky gut conditions.
What is Larazotide?
Larazotide acetate is a synthetic peptide derived from Vibrio cholerae zonula occludens toxin (ZOT). Unlike ZOT which opens tight junctions, larazotide acts as a tight junction regulator that prevents pathological opening of intestinal tight junctions. It has undergone multiple Phase 2 and Phase 3 clinical trials for celiac disease and is also being studied for MIS-C (multisystem inflammatory syndrome in children) and other barrier-dysfunction conditions.
What Larazotide Is Investigated For
Larazotide is investigated primarily as an adjunctive therapy for celiac disease — a tight junction regulator designed to block zonulin-mediated paracellular opening and reduce symptoms from inadvertent gluten exposure in patients already on a gluten-free diet. It reached Phase 3 as the most clinically advanced investigational peptide for celiac, earned FDA Fast Track designation, and generated positive Phase 2 signals at 0.5 mg three-times-daily pre-meal. The central fact, however, is that the Phase 3 CeDLara trial did not meet its primary endpoint in 2022, leaving the regulatory path forward uncertain and prompting reassessment of the zonulin-pathway hypothesis itself. Extensions to 'leaky gut,' MIS-C, and other barrier conditions rest on smaller case series and preclinical work rather than confirmatory RCTs. Larazotide is a locally-acting orally dosed peptide with minimal systemic absorption and a generally good short-term tolerability profile — but as of current review, it is clinically unvalidated, not approved, and not a substitute for a gluten-free diet.
History & Discovery
Larazotide acetate (AT-1001) was developed from work originating in the laboratory of Alessio Fasano in the early 2000s, where researchers identified zonulin — a human protein homologous to Vibrio cholerae's zonula occludens toxin (ZOT) — as a physiologic regulator of intestinal tight junctions. The mechanistic insight was that gluten exposure in celiac disease triggers zonulin release, which opens paracellular tight junctions and allows immunogenic gluten peptides to cross the epithelial barrier and drive the autoimmune response. Larazotide was engineered as an eight-amino-acid zonulin-pathway antagonist designed to block this pathological opening. Alba Therapeutics led early clinical development; the program was subsequently acquired by Innovate Biopharmaceuticals, which became 9 Meters Biopharma. Through the 2010s and early 2020s, larazotide became the most clinically advanced non-dietary investigational agent for celiac disease, reaching Phase 3 as the CeDLara trial. In 2022, CeDLara's topline readout reported that larazotide did not meet its primary endpoint for reduction of celiac symptoms in gluten-exposed patients on a gluten-free diet. The failure was a significant setback for the zonulin-pathway hypothesis as a pharmacologic target in celiac and for 9 Meters Biopharma, which subsequently underwent corporate restructuring. As of the site's current revision, larazotide has no FDA-approved indication, and its regulatory future in celiac disease is uncertain. Research activity has continued in adjacent indications (MIS-C in pediatrics, acute mucosal barrier conditions), but the celiac program's Phase 3 miss remains the central fact of the drug's clinical trajectory.
How It Works
Larazotide acts like a gatekeeper for the spaces between cells in your gut lining. It helps keep these gates properly closed, preventing unwanted substances from leaking through the intestinal barrier into your bloodstream.
Larazotide acetate acts as a zonulin receptor antagonist, preventing zonulin-mediated disassembly of tight junction proteins (claudins, occludin, ZO-1). It blocks the myosin light chain kinase (MLCK) pathway that leads to cytoskeletal contraction and tight junction opening. By maintaining tight junction integrity, it reduces paracellular permeability and prevents translocation of gluten peptides and other antigens.
Evidence Snapshot
Human Clinical Evidence
Strong. Multiple Phase 2 and Phase 3 clinical trials with hundreds of patients. FDA Fast Track designation received.
Animal / Preclinical
Extensive. Well-characterized in animal models of intestinal permeability.
Mechanistic Rationale
Strong. Zonulin pathway and tight junction biology are well-understood.
Research Gaps & Open Questions
What the current literature has not yet settled about Larazotide:
- 01The Phase 3 CeDLara miss — whether the failure reflected mechanism limitations, trial design (endpoint choice, gluten-exposure control, patient selection), or dose selection (the non-monotonic dose-response pattern that led to 0.5 mg) remains debated; definitive attribution would require additional Phase 3 work that is not currently planned.
- 02Role in non-celiac barrier conditions — MIS-C, acute liver failure with gut origin, and other acute mucosal barrier conditions have generated small positive signals in case series and preclinical work; adequately powered trials would be needed to establish clinical utility.
- 03The zonulin-pathway hypothesis itself — larazotide's Phase 3 result has prompted reassessment of how central zonulin-mediated tight junction dysregulation is to celiac pathology, and whether the antagonist approach engaged the relevant biology.
- 04Long-term safety — although larazotide has been generally well-tolerated in shorter trials, multi-year safety data in any population is limited.
- 05'Leaky gut' as a pharmacologic target — outside of celiac disease, the clinical utility of pharmacologically modulating intestinal permeability in functional GI disorders, irritable bowel syndrome, or autoimmune conditions has not been adequately studied.
- 06Research-chemical quality — the identity, purity, and potency of larazotide sold outside of trial programs has not been independently verified and represents a significant unknown for anyone using it outside of clinical research.
Forms & Administration
Larazotide is taken orally as a capsule, typically three times daily before meals. This oral route is a significant advantage for patient compliance.
Dosing & Protocols
The ranges below reflect protocols commonly discussed in the literature and by clinicians — not a prescription. Actual dosing for any individual should be determined by a qualified healthcare provider who knows the patient.
Typical Range
In the Phase 2 and Phase 3 celiac programs, larazotide was dosed as oral capsules at 0.5 mg three times daily, taken 15 minutes before meals. Earlier Phase 2 work explored 0.25 mg, 1 mg, and 2 mg three-times-daily regimens; the 0.5 mg dose was selected for Phase 3 based on a non-monotonic dose-response pattern in which the lowest tested dose produced the most robust effect — itself an unusual finding that complicated later interpretation. No FDA-labeled dose exists.
Frequency
Three times daily, timed 15 minutes before the main meals (breakfast, lunch, dinner). The pre-meal timing reflects the mechanistic intent: larazotide acts locally in the intestinal lumen, and the goal is to have drug present at tight junctions when gluten peptides or other triggers arrive post-meal. Unlike systemically absorbed drugs, larazotide is not expected to accumulate and dosing is timed to food, not to steady-state plasma concentrations.
Timing Considerations
No specific timing requirements: can be administered at any time of day, with or without food, and is not tied to exercise timing. Consistency matters more than the specific clock — dose at roughly the same time each day (or same day each week, for weekly protocols) to keep exposure steady.
Cycle Length
In the celiac program, larazotide was studied as chronic adjunctive therapy to a gluten-free diet, with the intent of providing protection against inadvertent gluten exposure on a continuous basis. Typical trial exposure periods ran 12–52 weeks. Because larazotide is not FDA-approved and Phase 3 missed its primary endpoint, there is no established chronic-use regimen outside of clinical trials.
Protocol Notes
Larazotide's mechanism is intentionally local: as an eight-amino-acid peptide taken orally, it is presumed to act in the intestinal lumen without significant systemic absorption. This is a feature, not a limitation — systemic exposure to a tight-junction-regulating peptide would raise broader concerns. The lack of systemic absorption also means larazotide does not have the typical pharmacokinetic parameters (peak plasma concentration, half-life, clearance) that dominate the discussion of most peptides on this site. An important practical note: larazotide sold through research-chemical suppliers as 'zonulin antagonist for leaky gut' is removed from its clinical context. The Phase 3 program failed to demonstrate symptomatic benefit in celiac disease — the best-characterized zonulin-driven barrier condition — and the clinical case for using larazotide to address looser, less-validated 'leaky gut' framings is correspondingly weaker. Quality, potency, and identity of research-chemical larazotide cannot be assumed to match what was used in the clinical program.
Larazotide is not FDA-approved for any indication. The Phase 3 CeDLara trial in celiac disease did not meet its primary endpoint in 2022. Access outside of a registered clinical trial is not legitimate, and research-chemical sourcing is unverified.
Timeline of Effects
Onset
In trials, any symptomatic effect of larazotide was intended to emerge over weeks of continuous pre-meal dosing, not acutely after individual gluten exposures. Phase 2 studies that used gluten-challenge paradigms found modest reductions in some celiac symptoms and antibody markers at the 0.5 mg dose, with effect sizes measured over treatment periods of 4–6 weeks.
Peak Effect
Peak symptomatic effect in Phase 2 was modest — reductions in abdominal symptoms on patient-reported outcome scales at 4–6 weeks. The Phase 3 CeDLara trial, designed to confirm and extend these effects over a longer period, did not show statistically significant separation from placebo on its primary symptom endpoint. This is the central data point for understanding larazotide's clinical peak: a positive Phase 2 signal that did not replicate at Phase 3 scale.
After Discontinuation
Because larazotide is intended to act locally in the intestinal lumen and does not appear to have meaningful systemic accumulation, any protective effect would be expected to recede within the dosing interval — hours to days — after discontinuation. There is no long-term residual effect after stopping.
Common Questions
Who Larazotide Is NOT For
- •Pregnancy and breastfeeding — human safety data is limited; trial exclusion criteria have typically required effective contraception.
- •Pediatric use — except within specific trial programs (such as the MIS-C case series work), larazotide has not been adequately studied in pediatric populations.
- •Known hypersensitivity to larazotide or to the excipients used in oral capsule formulation.
- •Conditions where baseline intestinal barrier function is fundamentally structurally altered (extensive inflammatory bowel disease with active stricturing, advanced short-gut syndrome) — clinical data in these populations is minimal and the mechanistic target may not be the rate-limiting step.
- •Concurrent participation in other investigational gastrointestinal agent trials — for practical interaction and confounding reasons.
Drug & Supplement Interactions
Because larazotide is designed to act locally in the intestinal lumen with minimal systemic absorption, classical pharmacokinetic drug-drug interactions via hepatic metabolism, plasma protein binding, or renal clearance are not the primary concern. The more plausible interaction domain is intestinal: larazotide's effect on paracellular permeability could in principle alter the absorption of other orally administered drugs whose bioavailability depends on tight-junction-mediated uptake. In practice, most clinically important orally absorbed drugs use transcellular rather than paracellular routes, so the magnitude of this theoretical interaction is likely small. Clinical trials have not systematically characterized interactions with common co-medications, and the absence of post-marketing use means real-world interaction data is sparse. Patients using larazotide through any channel should disclose it to their prescribing clinicians as they would any investigational agent.
Safety Profile
Common Side Effects
Cautions
- • Not yet FDA-approved
- • Not a replacement for gluten-free diet
- • Clinical trial data is promising but approval pending
What We Don't Know
Long-term effects of chronic tight junction modulation are being studied. Post-marketing safety data is not yet available.
Legal Status
United States
Larazotide is not FDA-approved for any indication as of the site's current revision. It received FDA Fast Track designation for celiac disease during its development program, but the Phase 3 CeDLara trial did not meet its primary endpoint in 2022, and the regulatory pathway in celiac disease is uncertain. The drug's sponsor (9 Meters Biopharma, previously Innovate Biopharmaceuticals, previously Alba Therapeutics) has undergone corporate transitions that have further complicated the development trajectory. Access is limited to any ongoing clinical trials that may be enrolling; legitimate prescription access is not currently available.
International
No regulatory authority has approved larazotide for marketing in any major jurisdiction. Investigational use has occurred at clinical trial sites in the US, EU, and select other regions.
Sports & Competition
Larazotide is not named on the WADA Prohibited List. It is a locally acting intestinal peptide with no plausible performance-enhancing mechanism, and athletes are unlikely to encounter regulatory issues specific to this compound — though the broader WADA S0 framework (unapproved investigational agents) technically applies.
Regulatory status changes over time. Verify current local rules with a qualified professional.
Myths & Misconceptions
Myth
Larazotide is close to FDA approval for celiac disease.
Reality
The Phase 3 CeDLara trial did not meet its primary endpoint in 2022, and the regulatory path forward in celiac disease is uncertain. Larazotide had FDA Fast Track designation before that readout, but Fast Track confers expedited review, not approval, and a failed pivotal trial substantially disrupts the approval timeline. As of the site's current revision, there is no near-term FDA approval pathway for larazotide in celiac disease.
Myth
Larazotide fixes leaky gut.
Reality
'Leaky gut' is a popular framing that ranges from well-characterized celiac barrier dysfunction to loose hypothesis-level descriptions in functional GI conditions. Larazotide's best-studied indication — celiac disease — failed Phase 3. Extending the drug's use to broader 'leaky gut' scenarios, which have weaker evidence for zonulin-mediated pathology in the first place, is not supported by clinical trial data. The mechanism is scientifically coherent; the clinical translation has been more limited than the mechanistic story suggests.
Myth
Larazotide lets people with celiac disease eat gluten safely.
Reality
Even in its best Phase 2 data, larazotide was never designed or positioned as permission to consume gluten. Its intended role was adjunctive protection against inadvertent gluten exposure in patients already on a strict gluten-free diet. A gluten-free diet remains the only established treatment for celiac disease, and even under the most generous interpretation of larazotide's data, deliberately consuming gluten is not what the drug was developed to enable.
Myth
Research-chemical larazotide is as good as clinical larazotide.
Reality
Larazotide sold through research-chemical channels has not been independently verified for identity, purity, or potency against the material used in 9 Meters Biopharma's clinical program. Even if the molecule were identical, the Phase 3 clinical data in celiac disease did not show symptomatic benefit at the studied dose and schedule — so the mechanistic bet is not actually validated clinically. Research-chemical use combines unverified product with an unproven clinical case.
Published Research
34 studiesLarazotide Acetate Protects the Intestinal Mucosal Barrier from Anoxia/Reoxygenation Injury via Various Cellular Mechanisms
Antibacterial hyaluronic acid hydrogel with sustained release of larazotide as effective colitis treatment
Viral spike antigen clearance and augmented recovery in children with post-COVID multisystem inflammatory syndrome treated with larazotide
The PAR2 Antagonist Larazotide Can Mitigate Acute Histamine-Stimulated Epithelial Barrier Disruption in Keratinocytes: A Potential Adjunct Treatment for Atopic Dermatitis
Ameliorative Effects of Larazotide Acetate on Intestinal Permeability and Bacterial Translocation in Acute Pancreatitis Model in Rats
Zonulin Antagonist, Larazotide (AT1001), As an Adjuvant Treatment for Multisystem Inflammatory Syndrome in Children: A Case Series
Effects of larazotide acetate, a tight junction regulator, on the liver and intestinal damage in acute liver failure in rats
Peptide Derivatives of the Zonulin Inhibitor Larazotide (AT1001) as Potential Anti SARS-CoV-2: Molecular Modelling, Synthesis and Bioactivity Evaluation
Larazotide acetate for treatment of celiac disease: A systematic review and meta-analysis of randomized controlled trials
Multisystem inflammatory syndrome in children is driven by zonulin-dependent loss of gut mucosal barrier.
Larazotide acetate induces recovery of ischemia-injured porcine jejunum via repair of tight junctions
Larazotide acetate: a pharmacological peptide approach to tight junction regulation
In vivo assessment of a delayed release formulation of larazotide acetate indicated for celiac disease using a porcine model
Tight junction regulation in celiac disease: role of larazotide acetate
In silico Analysis Revealed Potential Anti-SARS-CoV-2 Main Protease Activity by the Zonulin Inhibitor Larazotide Acetate
The Therapeutic use of the Zonulin Inhibitor AT-1001 (Larazotide) for a Variety of Acute and Chronic Inflammatory Diseases
Targeting zonulin and intestinal epithelial barrier function to prevent onset of arthritis.
The α3β4 nAChR partial agonist AT-1001 attenuates stress-induced reinstatement of nicotine seeking in a rat model of relapse and induces minimal withdrawal in dependent rats
[Larazotide as an option in case of failure of a gluten-free diet]
The potential utility of tight junction regulation in celiac disease: focus on larazotide acetate
High affinity α3β4 nicotinic acetylcholine receptor ligands AT-1001 and AT-1012 attenuate cocaine-induced conditioned place preference and behavioral sensitization in mice
AT-1001 Is a Partial Agonist with High Affinity and Selectivity at Human and Rat α3β4 Nicotinic Cholinergic Receptors
Pharmacological stress is required for the anti-alcohol effect of the α3β4* nAChR partial agonist AT-1001
Larazotide acetate for persistent symptoms of celiac disease despite a gluten-free diet: a randomized controlled trial
AT-1001: a high-affinity α3β4 nAChR ligand with novel nicotine-suppressive pharmacology
Functional characterization of AT-1001, an α3β4 nicotinic acetylcholine receptor ligand, at human α3β4 and α4β2 nAChR
Commentary: larazotide acetate - an exciting new development for coeliac patients? Authors' reply
Commentary: larazotide acetate - an exciting new development for coeliac patients?
Larazotide acetate in patients with coeliac disease undergoing a gluten challenge: a randomised placebo-controlled study
A randomized, double-blind study of larazotide acetate to prevent the activation of celiac disease during gluten challenge
Larazotide acetate promotes tight junction assembly in epithelial cells
Larazotide acetate regulates epithelial tight junctions in vitro and in vivo
Reducing small intestinal permeability attenuates colitis in the IL10 gene-deficient mouse.
The safety, tolerance, pharmacokinetic and pharmacodynamic effects of single doses of AT-1001 in coeliac disease subjects: a proof of concept study
Quick Facts
- Class
- Tight Junction Regulator
- Tier
- B
- Evidence
- Moderate
- Safety
- Well-Studied
- Updated
- Mar 2026
- Citations
- 34PubMed
Also known as
Tags
Peptide Families
Related Goals
Conditions Discussed
Evidence Score
Clinical Trials
View Clinical TrialsLinks to ClinicalTrials.gov for reference. Listing does not imply endorsement.