L-glutamine is an amino acid that supports a healthy intestinal lining and immune function, and assists in healing after injury or surgery and in muscle cell repair. Evidence suggests supplemental L-glutamine benefits gastrointestinal health, supports wound healing, maintains immune health, and helps restore plasma glutamine levels depleted after periods of physical stress, such as prolonged exhaustive exercise. L-glutamine is the most prevalent amino acid in the bloodstream. It is found in high concentration in the gastrointestinal tract, which is its greatest user. Various stress factors – such as trauma, infection, malnutrition, chemotherapy,
injury, and high-level athletic training – can adversely affect absorption in the small intestine, leading to food allergies. In numerous animal studies, the addition of L-glutamine improved absorption, as well as the gut's immune function.
Skeletal muscles contain the greatest intracellular concentration of L-glutamine. But that concentration can be adversely affected by various insults, including injury, infection, chronic stress, malnutrition, and glucocorticoid use. Intense exercise lowers blood levels of glutamine, which can remain low if intense training is repeated without adequate recovery. Research indicates L-glutamine supplementation can offset these conditions.