Evidence Level
Moderate
L-Glutamine has strong mechanistic rationale as the primary fuel for intestinal epithelial cells. Clinical evidence supports its role in preserving gut barrier function during physiological stress (surgery, critical illness, intense exercise). For "leaky gut" in otherwise healthy adults, the evidence is moderate — mechanistic studies are strong, but large RCTs in the functional GI population are still limited. Integrative gastroenterologists commonly recommend 5-10g daily as part of gut repair protocols.