Larazotide: a zonulin antagonist that reached phase IIb and stopped there
Most peptides discussed for gut health have never been in a controlled human trial. Larazotide has been in several, in a real patient population, with a real endpoint — and it still is not approved. The gap between those two facts is the useful part of this page.
Regulatory status. Phase IIb clinical trials completed. Not FDA approved. IND status in US. That is the app’s own field, reproduced here rather than summarised. It means no regulator has reviewed a manufacturer’s evidence for identity, purity, potency or safety in people for this compound, so nothing below is a marketing claim about a product you can buy.
Purity, identity and concentration are therefore unverified by anyone but whoever made the vial. The storage rule in the fact box below is general practice for this formulation rather than a specification for a particular product: General handling practice for this formulation. Your supplier’s own insert or COA overrides anything here.
This page names no vendor, no clinic and no testing service, and there is no discount code anywhere on this site — the moment a page like this recommends where to buy, it stops being information.
- Also known as
- AT-1001, INN-202
- Class
- Peptide
- Regulatory status
- Phase IIb clinical trials completed. Not FDA approved. IND status in US.
- Before mixing
- Sealed powder refrigerated at 2–8 °C (36–46 °F), or frozen if it will sit for months. Keep it dark and dry. Kits are usually ten vials — only the vial you mix comes out of the freezer.
- After mixing
- Reconstituted, refrigerate at 2–8 °C and use within about 28 days if you mixed it with bacteriostatic water. Plain sterile water has no preservative and should be treated as a single day’s worth. This is swallowed rather than injected, so sterility matters less than it would for a shot — but the peptide degrades on the same clock either way.
- What ruins it
- Do not freeze a reconstituted vial. Do not leave it on the counter between doses — three doses a day before meals means three trips to the fridge, not a vial that lives in a gym bag.
- Handling caveat
- General handling practice for this formulation. Your supplier’s own insert or COA overrides anything here.
Zonulin, tight junctions and a specific mechanism
Established clinical use The cells lining the small intestine are sealed to one another by tight junctions, protein complexes that decide what crosses between cells rather than through them. Zonulin is a signalling protein that loosens those junctions. In celiac disease, gluten fragments trigger zonulin release, permeability rises, and immunogenic peptides reach the tissue underneath. Larazotide is an eight-amino-acid peptide that antagonises that pathway, and it is designed to act in the gut lumen rather than systemically.
That is a narrower and better-specified mechanism than most of this category offers. It is worth contrasting with BPC-157, which is discussed for gut repair on the basis of animal healing models and has no human trial data at all. Larazotide targets one protein interaction and was tested against a clinical endpoint; BPC-157 is a broader claim with a thinner base. The app’s own notes put them together as complementary, and the honest version of that is that one of them has been measured in patients.
Because the peptide is meant to work at the epithelial surface, systemic absorption is low by design. That is a deliberate feature, not a limitation, and it explains why the route is oral rather than injected.
What the trials actually found
Off-label or community practice Larazotide has been through phase II trials in celiac disease in patients already following a gluten-free diet but still symptomatic. A phase IIb study reported a reduction in symptom scores at the lowest of the doses tested, with the higher doses performing no better — an inverted dose response that the investigators discussed openly and that is unusual enough to be worth stating plainly.
A phase III trial was subsequently begun and was discontinued after an interim analysis indicated it was unlikely to meet its primary endpoint. That is the most important sentence on this page, and it is the one that marketing copy for the peptide tends to omit. Phase IIb data is a reason to keep studying a compound; it is not evidence of benefit, and here the larger, better-powered study did not confirm it.
Animal-only or theoretical Uses outside celiac disease — irritable bowel syndrome, non-alcoholic steatohepatitis, the broad idea of “leaky gut” as a driver of systemic disease — rest on the mechanism rather than on outcome data. Intestinal permeability is measurable and is genuinely abnormal in several conditions. Whether reducing it changes how a person feels is a separate question, and outside celiac disease it has not been answered.
What to watch, and what there is to watch with
The app records symptom tracking, inflammatory markers and zonulin levels through specialty laboratories. Serum zonulin assays are worth a caution: the commercial tests have been criticised for measuring proteins other than the intended target, so a number from one is weaker evidence than it appears. Symptom scores kept consistently over weeks are the more defensible measurement here.
Tolerability across the trials was broadly comparable to placebo, with gastrointestinal complaints the most commonly reported events on both arms. That is a reassuring profile within a trial population and a defined duration, and it says nothing about use for longer than the twelve weeks studied. Anyone with celiac disease considering this should be discussing it with the gastroenterologist already managing the diagnosis, not substituting it for the gluten-free diet the trials required participants to stay on.
Established clinical use Sourcing is a real constraint. The compound is an investigational drug under an IND, not a supplement, so material sold outside that framework is not the trial product and no one has verified that it is the same molecule at the same purity. This site names no vendor and this page does not tell you where to get it.
The dosing rows the app records
Off-label or community practice Reproduced from the app’s reference so you can see what it holds, not as a recommendation. Which row applies to a particular person, if any, is a clinical decision this page does not make — and rows describing supraphysiological or post-cycle use are filtered out before this table is built, so what you see here is a subset.
| Label | Amount | Route and frequency | Duration recorded |
|---|---|---|---|
| Gut Permeability and Celiac | 0.5-1mg | Oral 3x daily before meals | 12 weeks |
What the app monitors alongside it
The panel below is the app’s own monitoring note for Larazotide, verbatim. None of the analytes it names has a page here yet.
- Monitoring panel
- GI symptom tracking, zonulin levels if available via specialty labs, inflammatory markers.
Drawbacks and risks the app records
From the app’s own entry. The first line understates the position — the phase III programme was stopped early, which is more than an absence of approval.
- Not FDA approved despite advanced trials
- Oral bioavailability variable
- Long-term effects beyond trial periods unknown
- Celiac-specific data — other conditions still being studied
- Sourcing limited
- May need dietary changes alongside for full effect
Questions people actually ask
Is larazotide approved anywhere?
No. It has been through phase II trials in celiac disease and a phase III trial that was discontinued at interim analysis. It has no marketing approval in any jurisdiction.
Does it replace a gluten-free diet?
Nothing in the trial programme supports that. Participants remained on a gluten-free diet throughout; the peptide was studied as an addition for people who were still symptomatic despite the diet.
Is it the same idea as BPC-157?
No. Larazotide antagonises one signalling pathway at the tight junction and was tested against a clinical endpoint in patients. BPC-157 is a broad tissue-repair claim resting on animal models with no human trials.
Can I test my own zonulin?
Specialty laboratories offer it, and the assays have been criticised for cross-reactivity with other proteins. Treat a result as suggestive at best, and take a consistent symptom record more seriously than a single number.
Where the load-bearing numbers come from
Named rather than linked. Publisher URLs move, and a citation that resolves to a 404 two years from now is worse than one you can search for by name — every entry below is findable from the title and year alone.
- Zonulin regulates intestinal tight junctions
- Established mechanism in gastrointestinal physiology
- Phase IIb symptom reduction in celiac disease
- Randomised trial in diet-adherent symptomatic patients; benefit at the lowest dose tested
- Phase III discontinued at interim analysis
- Sponsor announcement of futility; the confirmatory evidence does not exist
- Use for IBS, NASH or general permeability
- Mechanistic extrapolation only; no completed outcome trials
- Oral route with low systemic absorption
- By design; the target is at the luminal surface
A compound assessed on symptom scores needs the symptoms written down consistently. TherapyLog keeps the dose and the daily record in one place.
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