Glutamine Side Effects
Very few side effects of glutamine have been reported, but there has been one case of high liver enzymes probably related to IV glutamine supplementation. It has also been reported that the supplement may cause mania in people with bipolar disorder. There are also some theoretical side effects that could occur, but these have not been shown to be a problem in humans.
As with any medication or supplement, side effects are possible with glutamine (also known as L-glutamine). Many people assume that natural products such as glutamine are always free from problems. However, this is simply not the case.
It is reasonable to assume that any supplement potent enough to have medicinal properties may also have side effects. Although very few glutamine side effects have been reported, this does not mean negative reactions aren't possible.
In general, studies have reported no significant side effects with glutamine supplementation. There has been one case of high liver enzymes, probably related to IV glutamine supplementation, and it has been reported that glutamine supplementation may cause mania in people with bipolar disorder (also known as manic depression).
Some people find the grittiness of glutamine powder to be rather unpleasant when taken orally. Trying different products may help with this problem.
There are some concerns that glutamine could cause certain side effects based on how it works in the body. However, these theoretical problems have not been shown to be a concern in humans. Since rapidly growing tumor cells use glutamine as a fuel, there is concern that the supplement may cause or worsen cancer, although studies have not shown this to be the case.
There is also concern that high doses of glutamine could cause side effects in the brain, such as psychological problems, due to a buildup of glutamate and ammonia, since the body can break down glutamine into ammonia and glutamate. In theory, the supplement may also increase the risk of seizures.