Library / Peptides / Gut & Inflammation / Larazotide

Emerging evidence · Grade B

Larazotide

Larazotide (AT-1001)

Score

76 / 100

Class

Gut & Inflammation

Brand

AT-1001

Status

Emerging

TL;DR

Larazotide (AT-1001) is an experimental oral peptide that was tested as a helper to the gluten-free diet for people with celiac disease who still feel unwell despite avoiding gluten. It is meant to act only inside the gut — tightening the junctions between gut-lining cells so fewer gluten fragments slip through — and is barely absorbed into the body. In trials the results were mixed: it did not reliably change a lab measure of gut "leakiness," but at one low dose it was associated with modest symptom relief and was generally well tolerated. It reached late-stage testing but that program was stopped, and it is NOT FDA-approved. For now, the proven approach to celiac disease remains a carefully managed gluten-free diet under medical and dietitian guidance.

Part 01 · How it works

Mechanism.

Larazotide (also called larazotide acetate or AT-1001) is an oral eight-amino-acid peptide that acts as a "tight-junction regulator" in the gut lining. It was studied as an add-on to the gluten-free diet for people with celiac disease who still have symptoms despite avoiding gluten. Because it is barely absorbed into the bloodstream, it works locally inside the intestinal lumen rather than systemically. It advanced through phase 2 trials and into a phase 3 program but is NOT FDA-approved for any use, and its late-stage development has been discontinued.

Picture the gut lining as a brick wall whose bricks are held together by mortar. In celiac disease, gluten loosens that mortar so unwanted fragments slip between the bricks and alarm the immune system. Larazotide is studied as a kind of mortar-stabilizer applied to the wall's surface, aiming to keep the gaps from widening when gluten shows up — it patrols the wall rather than entering the bloodstream behind it.

Mechanism · technical

Larazotide is a synthetic octapeptide that antagonizes zonulin, a protein that loosens the tight junctions binding intestinal epithelial cells together. In celiac disease, gluten-triggered zonulin release is thought to open these junctions, allowing gluten peptides to cross the epithelium into the lamina propria, where they provoke a tissue-transglutaminase and T-cell-mediated immune response. By acting at the apical surface of the gut lining to keep tight junctions closed, larazotide is proposed to limit paracellular passage of gluten fragments. It has minimal systemic absorption and is designed to act within the gut lumen.

Part 02 · Dosing & administration

How it's taken.

Clinical · trial-validated

Values below describe how Larazotide has been administered in human clinical trials and/or approved labeling. Provided for educational purposes only — this is not medical advice and not instructions for self-administration. Consult your healthcare provider before making any health decision.

Standard dose

Studied at ~0.25–8 mg three times daily in trials; 0.5 mg three times daily was the only dose that separated from placebo in phase 2b. No FDA-approved or recommended consumer dose exists.

Oral · Three times daily before meals (as used in clinical trials)

Duration

Trial durations generally ran 2 weeks to 12 weeks; long-term use is not established

NOT FDA-approved; investigational only and phase 3 development discontinued. Larazotide acts locally in the gut lumen with minimal systemic absorption, so it was always studied as an adjunct to — not a replacement for — the gluten-free diet. The figures describe research dosing, not a regimen for self-administration; any product sold online is outside the FDA approval framework.

Need help with reconstitution?

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Part 03 · Safety

Side effects, rare serious events, who shouldn't.

Reported side effects

In clinical trials larazotide was generally well tolerated, with an adverse-event profile broadly similar to placebo and no serious drug-related safety signals reported. The most commonly reported events included headache, urinary tract infection, abdominal pain, nausea, diarrhea, and nasopharyngitis. Because absorption into the bloodstream is minimal, systemic side effects were uncommon in the studied populations. Long-term safety beyond the trial durations (generally up to several months) has not been established, and the safety of non-pharmaceutical or compounded versions sold outside clinical trials is unknown.

Absolute · do not use

Not FDA-approved — no established medical use; phase 3 development was discontinued

Pregnancy or breastfeeding (no safety data in these settings)

Known hypersensitivity to larazotide or any component of a given formulation

Should not be used as a substitute for a gluten-free diet in celiac disease

Not a substitute for medical evaluation of persistent celiac symptoms (which can have other causes)

Use of unregulated or research-chemical sources, where purity and identity are not assured

Interactions

Gluten-free diet (standard of care)

Larazotide was only ever studied as an adjunct to a gluten-free diet, not a replacement; relying on it to 'cover' gluten exposure is not supported by the evidence

Major

Orally administered medications

Larazotide acts at the intestinal barrier and is taken before meals; because robust co-administration interaction data are limited for an unapproved agent, theoretical effects on the absorption of other oral drugs cannot be excluded

Moderate

Other investigational celiac therapies (e.g., gluten-degrading enzymes)

No data on combined use; stacking unproven agents adds uncertainty without established benefit

Moderate

Live gluten challenge / intentional gluten intake

In studies, larazotide did not reliably prevent gluten-induced changes in the lactulose-to-mannitol permeability biomarker, so it should not be assumed to protect against deliberate gluten exposure

Moderate

Labs to monitor

Tissue Transglutaminase IgA (tTG-IgA)

Baseline and periodically per celiac follow-up

Standard serologic marker of celiac disease activity and dietary adherence; tracked in larazotide gluten-challenge studies

Total Serum IgA

Baseline (once)

Needed to interpret tTG-IgA, since selective IgA deficiency is more common in celiac disease and can cause false-negative results

Complete Blood Count (CBC)

Baseline and periodically

Screens for iron-deficiency anemia, a common consequence of celiac-related malabsorption

Iron Studies, Vitamin D, B12, Folate

Baseline and periodically

Celiac malabsorption commonly causes micronutrient deficiencies that warrant monitoring and repletion

Comprehensive Metabolic Panel

Baseline and as clinically indicated

General assessment of liver enzymes and nutritional/metabolic status in celiac disease

Part 04 · Evidence

How strong is the evidence?

Scores derived from rating, indexed studies, regulatory status, and catalogued safety data for this peptide. Curated per-peptide scoring replaces this when available.

Grade B

Grade B. Signal is real but maturing. Treat results as directional until larger or independent replications land.

Clinical efficacy

Emerging signal across multiple indexed studies; effect sizes still firming up.

Study quality

5 indexed studies in our dataset. Designs vary — see Research log for per-study grades.

Regulatory clarity

FDA-approved for at least one indication.

Safety profile

Based on 6 documented contraindications, 4 interactions, 5 lab checkpoints.

Long-term data

Long-horizon data not yet available outside research settings.

Part 05 · Research log

Every study we cite.

Each study with its published finding and a plain-language note on limitations or funding.

2015

Larazotide acetate for persistent symptoms of celiac disease despite a gluten-free diet — phase 2b randomized controlled trial

In a multicenter, double-blind, placebo-controlled trial of 342 adults with celiac disease symptomatic despite a gluten-free diet for at least 12 months, larazotide 0.5 mg three times daily met the primary endpoint, with fewer gastrointestinal symptoms than placebo over 12 weeks (mixed-model P = .005); the 1 mg and 2 mg doses were no different from placebo on any endpoint.

Industry-sponsored (Alba Therapeutics), with multiple company authors. Results were mixed and the dose-response was non-monotonic (only the lowest dose worked), raising concern about chance findings; the trial relied on symptom self-report rather than histology.

PMID 25683116 ↗

2012

Larazotide acetate to prevent activation of celiac disease during gluten challenge — randomized controlled trial

In 86 diet-controlled celiac patients given a 14-day gluten challenge, the urinary lactulose-to-mannitol permeability ratio did not differ significantly between larazotide and placebo, but some lower doses appeared to limit gluten-induced worsening of gastrointestinal symptom severity; the agent was generally well tolerated.

Industry-sponsored and small. The permeability biomarker was highly variable in the outpatient setting, which the authors said precluded an accurate assessment of the primary endpoint; symptom effects were secondary and exploratory.

PMID 22825365 ↗

2012

Larazotide acetate in coeliac disease undergoing a gluten challenge — randomised placebo-controlled study

In an exploratory trial of 184 celiac patients given 2.7 g of gluten daily for 6 weeks, no significant difference in the lactulose-to-mannitol ratio was seen between larazotide and placebo, but the 1 mg dose was associated with fewer gluten-induced symptoms (P = .002) and all doses showed lower rises in anti-tissue-transglutaminase IgA than placebo.

Industry-sponsored and explicitly described by the authors as exploratory and hypothesis-generating. The primary permeability endpoint was negative; the favorable symptom and antibody findings were secondary and require confirmation.

PMID 23163616 ↗

2021

Larazotide acetate for treatment of celiac disease — systematic review and meta-analysis of randomized controlled trials

Pooling four RCTs (626 patients), change in the lactulose-to-mannitol permeability ratio did not differ significantly between larazotide and placebo regardless of gluten status; in the gluten-challenge subgroup, larazotide was associated with greater improvement in gastrointestinal symptom rating scores and less gluten-related diarrhea, while no symptom benefit was seen in patients on a gluten-free diet alone.

All pooled trials were industry-sponsored. The authors concluded additional RCTs are warranted to validate the findings and noted the underlying permeability biomarker was inconsistent; benefits were limited to symptom subgroups.

PMID 34339872 ↗

2024

Celiac disease: hope for new treatments beyond a gluten-free diet — systematic narrative review

A systematic review of phase 1–3 celiac therapies grouped larazotide under agents that modulate intestinal permeability and prevent paracellular gluten uptake, and noted that as of review no celiac treatment — including larazotide — had completed a successful phase 3 trial, positioning such drugs as potential adjuncts to rather than replacements for the gluten-free diet.

Narrative review reflecting author selection and interpretation rather than pooled data. It summarizes a fast-moving pipeline; the discontinuation of larazotide's phase 3 program underscores that its late-stage efficacy was not established.

PMID 38648685 ↗

Part 06 · Cost & access

Where you can get it.

Regulatory status

Not FDA-approved for any indication. Larazotide (AT-1001) is an investigational peptide that completed phase 2 trials and entered a phase 3 trial (CeDLara) for celiac disease, but the late-stage program was discontinued by its developer (Innovate Biopharmaceuticals/9 Meters Biopharma) and it has not been approved by the FDA or any major regulator. It is not a controlled substance. It is not available as a prescription medication; any product marketed online as "larazotide" is sold outside the FDA approval framework and is not quality-assured as a finished drug.

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Part 07 · Your appointment

Questions to bring.

Larazotide is not FDA-approved and its phase 3 program was discontinued — what does that mean for whether I could ever access it?

I still have symptoms despite a strict gluten-free diet — what proven steps (dietitian review, checking for hidden gluten, ruling out other conditions) should we take first?

Are there any active clinical trials of tight-junction or other non-dietary celiac therapies I might qualify for?

If a compounded or research-chemical version of larazotide is sold online, what are the safety and quality risks of using an unapproved product?

References

Every citation, numbered.

Citation list. For our editorial read of each study — including bias flags and quality grades — see the Research log above.

01.
Larazotide acetate for persistent symptoms of celiac disease despite a gluten-free diet — phase 2b randomized controlled trial · 2015 · PMID 25683116 ↗
02.
Larazotide acetate to prevent activation of celiac disease during gluten challenge — randomized controlled trial · 2012 · PMID 22825365 ↗
03.
Larazotide acetate in coeliac disease undergoing a gluten challenge — randomised placebo-controlled study · 2012 · PMID 23163616 ↗
04.
Larazotide acetate for treatment of celiac disease — systematic review and meta-analysis of randomized controlled trials · 2021 · PMID 34339872 ↗
05.
Celiac disease: hope for new treatments beyond a gluten-free diet — systematic narrative review · 2024 · PMID 38648685 ↗