There is no standard glutamine dosage, since glutamine is a dietary supplement that is not regulated the same way as medications. In studies, doses ranging from 4 to 40 grams per day have been used (for oral use). When used as part of IV nutrition, the glutamine dosage is carefully calculated based on several factors, including body weight and the other components of IV nutrition.
Glutamine (L-glutamine) is an amino acid sometimes used in dietary supplements. It is important to note that unlike medications (for which the standard doses have been well established), there is less information for determining the best dose for supplements, including glutamine.
In studies, a wide range of glutamine dosages (4 to 40 grams per day) for oral use have been used. When used as part of IV nutrition, the glutamine dosage is carefully calculated based on several factors, including body weight and the other components of IV nutrition.
Because glutamine is not an essential amino acid (which means that it does not need to be obtained through the diet), there is no Recommended Dietary Allowance (RDA) for glutamine. Also, there is no Tolerable Upper Intake Level (UL, the "maximum dose") for glutamine, because there is not enough information to determine a safe maximum glutamine dose.
Since there is little strong evidence to guide you in your choice of a glutamine dosage, a good plan is to start with a reasonable dose (such as the recommended starting dose on the label of your glutamine product, or perhaps a little less) and see how your body reacts to that dose. If it seems to be working a little, but not quite well enough, perhaps a higher dose (but not more than recommended on the label) would be right for you. If you find that you are experiencing glutamine side effects, perhaps a lower dose would be better.