Thorne's L-Glutamine Powder is NSF Certified for Sport®. 

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 sensitivities. 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 help to offset these conditions.

Because an athlete needs to know that his or her supplements are trustworthy and compliant, every batch of an NSF Certified for Sport® product is tested for compliance with label claims and to ensure the absence of more than 200 substances banned by many major athletic organisations, including stimulants, narcotics, steroids, diuretics, beta-2 agonists, and masking agents.