About Tolerase G
AN-PEP (sold as Tolerase G, also in GliadinX) is a fungal prolyl endopeptidase that stays active at gastric pH and resists pepsin, cleaving proline-rich gluten epitopes into short non-immunogenic peptides before they reach the small intestine. Marketing positions it as protection against gluten cross-contamination. The honest read: human RCTs confirm it degrades gluten in the stomach (a pharmacodynamic endpoint), but the single clinical-outcome trial in celiacs on a gluten-free diet failed to beat placebo on stool gluten immunogenic peptides, serology, or symptom scores. It is a digestive aid for INCIDENTAL/hidden gluten only — NOT a treatment for celiac disease, and it does not make gluten safe for celiacs or replace a gluten-free diet. Brands implying otherwise overstate the evidence.
What Tolerase G supports
- Degrades incidental/hidden gluten in the stomach (RCT-confirmed mechanistically)
- Stays active at gastric pH and resists pepsin, unlike most digestive enzymes
How much Tolerase G to take
The RDA prevents deficiency. The effective range is what clinical trials used to actually move the outcome.
Effective
300–1200
mg
Trials dose in proteolytic units, not mass: König 2017 used 80,000-160,000 PPI per meal; Salden 2015 up to 174,000 PPI; the 2024 celiac trial used 650 mg/meal. Commercial Tolerase G products label ~300-1200 mg per gluten-containing meal; mg-to-PPI conversion is product-specific. Dose is per meal, not a daily total.
Clinical evidence
Limited clinical evidence. RCTs prove AN-PEP degrades gluten in the stomach (König 2017), but the only clinical-endpoint trial (celiacs on a gluten-free diet, 2024) found no reduction in stool gluten immunogenic peptides vs placebo and no change in serology or overall symptoms — mechanism is real, proven clinical benefit is not
NIH Fact Sheet