What Is Larazotide? Dosage, Half-Life & How to Track It

What Larazotide is and how it works

Larazotide (also known by its development code AT-1001) is a synthetic octapeptide developed specifically to address a mechanism in celiac disease: when someone with celiac eats gluten, a protein called zonulin gets released and loosens the tight junctions between intestinal cells, letting gluten fragments and other molecules cross into the bloodstream and trigger an immune reaction.

Larazotide is designed to block that zonulin-driven loosening, keeping the tight junctions closed even in the presence of gluten. That is a meaningfully different approach from a gluten-free diet: it does not neutralize gluten or prevent the immune system from recognizing it, it targets the permeability step that lets gluten reach immune tissue in the first place. It has been studied as an adjunct for people on a gluten-free diet who still have symptoms from accidental gluten exposure, not as a replacement for the diet itself.

Larazotide has gone through multiple Phase 2 trials and a Phase 3 trial (CeDLara) for celiac disease, making it one of the more clinically advanced compounds in this library — but it is still investigational, has not received FDA approval, and the Phase 3 trial was halted in 2022 for futility at an interim analysis, so approval is not guaranteed.

Typical dosing

Larazotide is taken orally, immediately before meals — the opposite administration pattern from most peptides in this library, which are typically injected because oral peptides are usually destroyed by digestion. Larazotide is specifically engineered to survive the gut and act locally on the intestinal lining without needing to be absorbed into the bloodstream, which is also why it has a favorable systemic safety profile in trials.

Clinical trial dosing has tested a range from 0.25–8 mg per dose, taken before each meal, with 0.5 mg three times daily emerging as the optimal dose in a Phase 2b trial among the range studied. There is no reconstitution step and no injectable form — it is a capsule or oral solution.

Half-life & what it means for frequency

Because Larazotide is engineered to act locally in the gut rather than enter systemic circulation, a conventional blood half-life is not the relevant number the way it is for an injectable peptide — trials report minimal systemic absorption, which is the point: the drug does its job at the intestinal lining and is largely excreted rather than distributed through the body.

That local mechanism is exactly why it is dosed before each meal rather than on a fixed daily clock — the goal is to have the tight junctions protected at the moment gluten exposure happens, not to maintain a constant blood level.

What to track & common side effects

Across clinical trials, Larazotide has been generally well tolerated, with the most common reported issues being mild GI symptoms — headache and gastrointestinal discomfort — similar in frequency to placebo in several trials, consistent with its minimal systemic absorption.

For someone using it as an investigational option, the practical thing to track is straightforward: whether the pre-meal dose actually happened (missing it defeats the local-protection mechanism) and GI symptom severity after known or suspected gluten exposure, to see whether the pattern is actually shifting.

Frequently asked questions