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Larazotide (AT-1001) is a synthetic octapeptide that has become the most clinically advanced tight junction regulator in published research, having progressed further through human clinical trials than any other zonulin-targeting compound. Developed originally by Alba Therapeutics and now held by 9 Meters Biopharma, larazotide acts as a zonulin antagonist — blocking the molecular pathway that regulates the opening and closing of tight junctions between intestinal epithelial cells.
Search interest in “larazotide peptide” has grown substantially as gut permeability research has expanded across celiac disease, inflammatory bowel disease, and the broader gut-brain axis literature. This guide covers the mechanism, the clinical trial data behind it, and sourcing considerations for researchers.
What Is Zonulin, and Why Does It Matter?
Zonulin is a protein — identified as the precursor to haptoglobin-2 — that physiologically modulates the permeability of tight junctions in the intestinal epithelium. Under normal conditions, zonulin release is tightly regulated. However, elevated gliadin (a gluten protein) exposure, certain gut bacteria, and other triggers can cause excessive zonulin release, opening tight junctions beyond their normal regulated state. This increased permeability — colloquially termed “leaky gut” — allows larger molecules, including undigested food antigens and bacterial components, to cross the intestinal barrier and interact with the immune system.
Dysregulated zonulin signaling has been implicated in research spanning celiac disease, type 1 diabetes, multiple sclerosis, and other autoimmune and inflammatory conditions where increased intestinal permeability is thought to play a mechanistic role.
Mechanism of Action
- Zonulin Receptor Antagonism: Larazotide binds at or near the zonulin receptor pathway, blocking zonulin’s ability to trigger tight junction disassembly
- Tight Junction Stabilization: Preserves the structural integrity of claudin and occludin-based tight junction complexes between enterocytes
- Localized, Non-Systemic Action: Larazotide is designed to act locally within the gut lumen with minimal systemic absorption — a key pharmacological feature that distinguishes it from systemically active compounds and is considered relevant to its favorable safety profile in trials
- Downstream Effect: By preventing pathological tight junction opening, larazotide reduces paracellular passage of antigens that would otherwise trigger immune activation in gluten-sensitive research models
Clinical Research Data
Phase 2b Celiac Disease Trial
The pivotal study establishing larazotide’s research profile was a Phase 2b randomized, double-blind, placebo-controlled trial in celiac disease patients who remained symptomatic despite adherence to a gluten-free diet. Key findings:
- Larazotide 0.5mg administered three times daily significantly reduced gastrointestinal symptom scores compared to placebo
- Improvements were observed in celiac disease patient-reported outcome (CeD PRO) measures
- Notably, symptom improvement occurred despite patients already maintaining a gluten-free diet — suggesting larazotide addresses residual gut permeability-driven symptoms not resolved by diet alone
- This makes larazotide the most clinically validated tight junction regulator published to date, ahead of other zonulin-pathway compounds still in earlier research stages
Additional Research Contexts
- Non-Celiac Gluten Sensitivity: Larazotide has been studied as a research tool for investigating symptom mechanisms in patients without confirmed celiac diagnosis but with gluten-related symptoms
- Inflammatory Bowel Disease: Gut barrier dysfunction is a recognized feature of IBD; larazotide is used in research models investigating whether restoring tight junction integrity affects disease activity
- Gut-Brain Axis Research: Because intestinal permeability has been proposed as a contributing factor in conditions with a gut-brain axis component, larazotide serves as a pharmacological tool to test the causal role of gut barrier integrity in these models
- Type 1 Diabetes: Preclinical models have investigated the zonulin pathway’s role in autoimmune diabetes onset, with larazotide used to test whether blocking zonulin-mediated permeability affects disease progression
Compound Specifications
| Property |
Value |
| Classification |
Synthetic octapeptide |
| Target |
Zonulin pathway / tight junction regulation |
| Molecular Weight |
825.9 Da |
| Developer |
Alba Therapeutics (now 9 Meters Biopharma) |
| Highest trial phase |
Phase 2b (celiac disease) |
| Systemic absorption |
Minimal — designed for local gut action |
Dosage Reference for Research
| Context |
Dose |
Route |
Notes |
| Phase 2b clinical trial |
0.5mg |
Oral |
3× daily |
| In vitro (Caco-2 permeability models) |
1–100 µM |
Apical media |
TEER and paracellular flux assays |
| Rodent gut permeability models |
0.1–1 mg/kg |
Oral gavage |
Zonulin-challenge protocols |
Research reference only. Not dosing guidance for human use.
Larazotide vs. Other Gut Barrier Research Compounds
| Compound |
Mechanism |
Clinical Stage |
| Larazotide (AT-1001) |
Zonulin receptor antagonist |
Phase 2b (most advanced) |
| BPC-157 |
NO/VEGF-mediated epithelial repair |
Preclinical (extensive rodent data) |
| KPV (Lysine-Proline-Valine) |
NF-κB suppression, barrier protein upregulation |
Preclinical |
Larazotide is mechanistically distinct from BPC-157 and KPV — it specifically blocks the zonulin pathway that opens tight junctions, whereas BPC-157 and KPV act more broadly on inflammation and epithelial repair. Researchers studying gut barrier integrity from a zonulin-specific angle typically select larazotide; those studying broader mucosal healing or inflammation often use BPC-157 or KPV, and some protocols combine mechanisms.
Where to Buy Larazotide for Research
Sourcing criteria for research-grade larazotide:
- HPLC purity ≥99% with published certificate of analysis
- Mass spectrometry confirmation of the octapeptide sequence
- Lyophilized format for long-term storage stability at −20°C, protected from light
- Third-party ISO-certified laboratory testing
HPLC Verified
Larazotide 5mg
Purity: 99%+ HPLC
Format: Lyophilized Powder
Testing: Third-Party COA
$95
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Frequently Asked Questions
What is larazotide used for in research?
Larazotide is used as a research tool to investigate the role of the zonulin pathway and intestinal tight junction permeability in disease models — primarily celiac disease, but also inflammatory bowel disease, non-celiac gluten sensitivity, and gut-brain axis research. It has reached Phase 2b clinical trials, the most advanced stage of any published zonulin antagonist.
Is larazotide the same as a gluten blocker?
No. Larazotide does not break down or neutralize gluten. It works downstream of gluten exposure by blocking the zonulin-mediated tight junction opening that allows gluten peptides and other antigens to cross the intestinal barrier. It addresses the permeability response, not the gluten itself.
How does larazotide compare to a gluten-free diet?
In the Phase 2b trial, larazotide reduced symptoms in celiac patients who were already following a strict gluten-free diet — meaning it addressed residual gut permeability-driven symptoms that diet alone did not resolve. This positions it as a potential complement to, not a replacement for, dietary gluten avoidance in research contexts.
Provided as educational and scientific reference. Larazotide is not approved for human use outside of clinical trials; material from Core Power Peptides is supplied strictly for in vitro and laboratory research, and researchers remain responsible for applicable local regulations.
