Glutamine or L-glutamine is a precursor of glutathione, an amino acid and anti-oxidant that occurs naturally in the body. It is used in the growth and repair of muscle tissue and as a fuel for cells in the intestine.

Glutamine is available as a nutritional supplement, often in combination with other anti-oxidants and vitamins.

Low levels of glutathione are seen in people with advanced HIV disease, and have been associated with high viral loads, low CD4 cell counts and reduced survival^[1]. Although it is not known whether low levels of glutathione are a cause or a symptom of disease progression, a test tube study found that glutathione can interfere with HIV replication. Support for this theory has come from one clinical study, which found improved immune markers and decreased viral load in people taking glutamine^[2].

Glutamine can also improve HIV-associated wasting, during which the body breaks down muscle to produce glutathione. Two randomised, placebo-controlled studies have shown that glutamine, taken alongside other supplements, can reverse muscle wasting and increase weight^[3][4]. There is also evidence that glutamine may improve intestinal function. One study compared glutamine with placebo as a treatment for leaky gut syndrome. A daily dose of 8g glutamine showed a trend towards improved intestinal function and better absorption of simple sugars. However, this result was not statistically significant and the researchers suggested that 20g of glutamine may be required to produce a significant effect^[5].

A daily dose of 30g glutamine can also improve diarrhoea, as can the more stable alanyl-glutamine^[6]. Glutamine has also been examined as a treatment for diarrhoea caused by nelfinavir (Viracept) and ritonavir-boosted lopinavir (Kaletra)^[7].

Glutamine comes in pill and powder form. The powdered form of glutamine should be dissolved in water or juice and taken immediately with food to increase absorption and reduce the chance of side-effects, such as upset stomach. It is taken three or more times a day. Experimental dosages for diarrhoea range from 5 to 40g a day.