What is it? Overview Usage Side Effects and Warnings

What is Glutamine?

Glutamine, or L-glutamine, is an amino acid derived from another amino acid, glutamic acid. Glutamine plays a role in the health of the immune system, digestive tract, and muscle cells, as well as other bodily functions. It appears to serve as a fuel for the cells that line the intestines. Heavy exercise, infection, surgery, and trauma can deplete the body's glutamine reserves, particularly in muscle cells.

The fact that glutamine does so many good things in the body has led people to try glutamine supplements as a treatment for various conditions, including preventing the infections that often follow endurance exercise, reducing symptoms of overtraining syndrome, improving nutrition in critical illness, alleviating allergies, and treating digestive problems.

Endurance athletes frequently catch cold after completing a marathon or similar forms of exercise. Preliminary evidence, including one small double-blind, placebo-controlled trial, suggests that glutamine supplements might help prevent such infections. 1 2 3 4 Another small double-blind, placebo-controlled trial suggests that glutamine might support standard therapy for angina . 5 Note: Angina is too dangerous a disease for self-treatment. If you have angina, do not take glutamine (or any other supplement) except on the advice of a physician.

Because, as noted above, cells of the intestine use glutamine for fuel, the supplement has been tried as a supportive treatment for various digestive conditions, with mixed results. Tested uses include reducing diarrhea...

Safety Issues

As a naturally occurring amino acid, glutamine is thought to be a safe supplement when taken at recommended dosages. There is strong evidence that glutamine is safe at levels up to 14 g per day, although higher dosages have been tested without apparent adverse effects. 6 Nevertheless, those who are hypersensitive to monosodium glutamate (MSG) should use glutamine with caution, as the body metabolizes glutamine into glutamate. Also, because many anti-epilepsy drugs work by blocking glutamate stimulation in the brain, high dosages of glutamine might conceivably overwhelm these drugs and pose a risk to people with epilepsy . Finally, in one case report, high doses of the supplement L-glutamine (more than 2 g per day) may have triggered episodes of mania...