Gluten challenge is a medically supervised process, whereby an individual already on a gluten-free diet (GFD) receives a specified amount of dietary gluten, to evaluate response in their clinical course, celiac serology, intestinal histology, and/or other parameters for diagnostic or research purposes. Gluten challenge is used in current clinical practice primarily as a complementary diagnostic test to differentiate between celiac disease (CeD) and other gluten-associated disorders (GADs), such as non-celiac gluten sensitivity (NCGS).