Evidence-based·Last reviewed May 30, 2026·How we grade evidence

Endopeptidase

EnzymeBest with a meal

Useful mainly for non-celiac people wanting a backstop against accidental gluten cross-contamination.

Quick decision guide

May help most

Non-celiac people wanting a backstop against accidental gluten cross-contamination

Common dosing range

A few hundred units of prolyl endopeptidase per meal

When to expect effects

Acts during the meal it is taken with

Watch out for

Not a treatment for celiac disease and will not make gluten safe to eat

What is it

Endopeptidases are enzymes that cleave peptide bonds within protein chains (rather than at the ends). In supplements, the term most often refers to prolyl endopeptidase preparations (such as Tolerase G), used to help break down gluten peptides.

Is it worth it for you?

Use this as a quick fit check, not a diagnosis.

Worth considering if…

You eat out and worry about trace gluten cross-contamination
You are non-celiac and tolerate small gluten amounts already
You want enzymatic backup, not dietary freedom

Probably skip if…

You have diagnosed celiac disease and need strict avoidance
You expect to eat full gluten meals safely
You have no gluten sensitivity at all

Evidence at a glance

breakdown of small amounts of dietary gluten

Limited Evidence
Effect
Partial degradation of trace gluten
Best fit
Non-celiac people exposed to accidental cross-contamination
Time
During the meal

Evidence for 1 use

AI-assisted evidence assessment — talk to your doctor before relying on any single supplement.

breakdown of small amounts of dietary gluten

Mechanism only
Limited Evidence

Prolyl endopeptidases cleave the proline-rich gluten peptides that resist ordinary digestive enzymes, and small studies show they can degrade modest amounts of gluten in the stomach and upper small intestine. Evidence is limited to enzymatic and short-term measures rather than protection from celiac-level exposures, and these enzymes are intended only for accidental cross-contamination.

Effect size
Partial degradation of trace gluten
Time to effect
During the meal
Best fit
Non-celiac people exposed to accidental cross-contamination
Less likely
People with celiac disease who require strict gluten avoidance

Bottom line: May help break down trace gluten but is not a substitute for a gluten-free diet in celiac disease.

SourceScricciolo et al., 2022 — PubMedStefanolo et al., 2024 — PMC

How it works

Prolyl endopeptidases cleave peptide bonds next to proline residues. The peptides produced from gluten during digestion are unusually proline-rich, which makes them resistant to ordinary digestive enzymes. Prolyl endopeptidases can degrade these proline-rich gluten peptides into smaller, less immunogenic fragments. In small clinical studies, prolyl endopeptidases (often combined with other enzymes such as glutenase) have been shown to help break down small amounts of dietary gluten in the stomach and upper small intestine. They are intended to handle accidental cross-contamination, not to allow people with celiac disease to eat gluten freely.

How to take it

1. Typical dose
A few hundred units of prolyl endopeptidase, per product labeling
2. Timing
With the first bites of a meal that may contain trace gluten
3. With food
With food
4. How long to try
Use situationally with at-risk meals rather than continuously

What to track

Whether incidental-exposure symptoms feel reduced
GI tolerance of the enzyme itself

1 commercial form

Compare the main delivery options and what they’re best suited for.

Tolerase G (Aspergillus niger prolyl endopeptidase)

Most studied form, used in 'gluten digest' enzyme supplements.

Acts in the stomach and upper small intestine; not absorbed systemically.

Safety

Know the common side effects, key cautions, and who should avoid it.

Common side effects

Mild gastrointestinal upset

Who should avoid it

  • People with celiac disease relying on it for protection

Pregnancy & breastfeeding

Limited data; pregnant women should consult a clinician before use.

Interactions

No significant interactions reported.

Choosing a product

What to look for on the label — and what to be skeptical of.

Look for…

Named prolyl endopeptidase or Tolerase G
Stated enzyme activity units per serving

Be skeptical of…

Eat gluten freely
Safe for celiac disease
Cures gluten intolerance

Frequently asked questions

Can I eat gluten safely with this enzyme if I have celiac disease?⌄

No. Studies have not demonstrated that prolyl endopeptidases protect against the immune damage from gluten in celiac disease. They may help with accidental small exposures, but a strict gluten-free diet is essential.

Will this help with gluten sensitivity or just celiac?⌄

Evidence is strongest for breaking down small gluten amounts in the lab and stomach. People with non-celiac gluten sensitivity may notice some symptom relief with cross-contamination but should still minimize gluten.

References by claim

breakdown of small amounts of dietary gluten

Scricciolo et al., 2022 — PubMed (2022) link

Stefanolo et al., 2024 — PMC (2024) link

Track Endopeptidase with Pilora

Set up dose reminders, check interactions, and join the community in the Pilora iPhone app.

Coming to App Store
Evidence-based·Last reviewed May 30, 2026·Evidence current as of May 30, 2026·How we grade evidence

Disclaimer: These statements have not been evaluated by the FDA. This page is educational, not a substitute for personalized medical advice. Evidence grades are AI-assisted assessments — talk to your doctor before starting any new supplement, especially if you’re pregnant, breastfeeding, on medications, or managing a chronic condition.