Larazotide (AT-1001, marketed as INN-202) is an octapeptide that modulates intestinal tight junctions. It’s one of the few peptides to reach Phase 3 clinical trials for “leaky gut” related conditions.
What Is Larazotide?
- Type: Octapeptide zonulin antagonist
- Target: Intestinal tight junctions
- Developer: Innovate Biopharmaceuticals (originally Alba Therapeutics)
- Clinical status: Phase 3 trials completed for celiac disease
Mechanism of Action
The Zonulin Pathway
- Zonulin is released in response to certain triggers (gluten, bacteria)
- Zonulin opens tight junctions between intestinal cells
- Increased intestinal permeability follows
- Immune activation from gut contents entering bloodstream
How Larazotide Works
- Blocks zonulin receptors on intestinal cells
- Prevents tight junction opening
- Maintains intestinal barrier integrity
- Reduces translocation of gut contents into bloodstream
Clinical Research
Phase 3 Trial Results (Celiac Disease):
- Patients on gluten-free diet + larazotide
- Significant reduction in celiac symptoms
- Reduced intestinal permeability markers
- Well-tolerated with minimal side effects
Other Studied Conditions:
- Celiac disease (primary focus)
- Type 1 diabetes (gut permeability link)
- Multiple sclerosis (gut-immune axis)
- General intestinal permeability
Current Status
As of 2026:
- FDA New Drug Application filed
- Approval pending
- Currently available through clinical trials or research suppliers
- Generic peptide available from peptide research companies
Dosing (Research Context)
| Parameter | Trial Doses |
|---|---|
| Dose | 0.5-1 mg, three times daily |
| Timing | Before meals (10-15 min) |
| Duration | Ongoing (chronic use in trials) |
| Administration | Oral |
Note: These are clinical trial doses. Individual research use varies.
Who Might Benefit?
- Celiac disease — reduce accidental gluten exposure symptoms
- Non-celiac gluten sensitivity — some overlap with zonulin pathway
- Suspected increased permeability — “leaky gut” presentations
- Autoimmune conditions — if gut permeability is a contributing factor
Side Effects
Generally well-tolerated in trials:
- Mild GI symptoms (nausea, bloating) occasionally
- No significant systemic effects
- No immunosuppression
Important Limitations
- Not FDA approved yet (pending)
- Doesn’t treat underlying conditions — manages permeability
- Won’t cure celiac — gluten-free diet still necessary
- Doesn’t help if tight junctions aren’t the issue
Larazotide vs Other Gut Peptides
| Compound | Target | Mechanism |
|---|---|---|
| Larazotide | Tight junctions | Zonulin antagonist |
| BPC-157 | Gut healing | Growth factors, inflammation |
| Colostrum peptides | Gut lining | Various growth factors |
Different mechanisms — could theoretically complement each other.
Sourcing
- Clinical trials (if eligible)
- Research peptide suppliers (for research use)
- Pending FDA approval for prescription access
The Honest Take
Larazotide is the rare gut peptide with legitimate clinical trial data. It’s not fringe — it went through Phase 3 trials. If you have celiac disease or suspected increased intestinal permeability, this is worth watching as it moves toward approval. For research use before approval, standard peptide sourcing caveats apply.
For gut healing peptides, see BPC-157 Guide. For other gut health approaches, see Gut Health Peptides.