Since the antioxidant capacity of IBD patients is compromised, many researchers have speculated that antioxidant therapies may benefit IBD patients.51 Although administration of glutathione is safe, research suggests that glutathione is poorly absorbed by the oral route.52–55 In contrast, oral γ-glutamylcysteine is readily absorbed by the PEPT1 and PEPT2 transporters, increases glutathione levels, and is safe for use in patients.56–65 Unfortunately, the commercial production of pure γ-glutamylcysteine is relatively cost-prohibitive. This evidence concerns the gene SLC15A2 and inflammatory bowel disease.