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Health Benefits, Uses, Side Effects & More


Updated June 25, 2014

Written or reviewed by a board-certified physician. See About.com's Medical Review Board.

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L-glutamine is an amino acid found in high levels throughout the body (primarily in skeletal muscle). It is also available in a number of foods and in dietary supplement form. L-glutamine supplements are often used to increase muscle mass, as well as treat certain health conditions.

L-glutamine has many functions in the body, including protein synthesis. It is also essential to proper function of the immune system. In addition, L-glutamine appears to play a role in brain function and digestion.

Health Benefits of L-Glutamine

Although research on the health effects of taking L-glutamine supplements is fairly limited and often dated, some studies suggest that L-glutamine supplements may offer certain health benefits. Here's a look at several key study findings:

1) Athletic Performance

There's little scientific evidence to support the claim that taking L-glutamine supplements is beneficial to athletes, according to a 2008 report published in the Journal of Nutrition. The report's authors note that, while many athletes take L-glutamine supplements to protect against exercise-related impairment of the immune system, L-glutamine supplementation does not appear to prevent post-exercise changes in immune function.

To date, few clinical trials have looked at the effects of L-glutamine supplements on sports performance. However, a small study published in the Journal of Sports Medicine and Physical Fitness in 1998 found that L-glutamine failed to enhance high-intensity exercise performance in a group of 10 male athletes.

READ MORE: Nutritional Supplements to Improve Sports Performance.

2) Cancer Treatment

Some studies indicate that L-glutamine may be beneficial to people undergoing cancer treatment. For a report published in Alternative Medicine Review in 1999, for instance, scientists looked at the available data on supplemental use of L-glutamine may help offset the muscle glutamine depletion that often occurs in cancer patients. In addition, the report's authors note that L-glutamine may help prevent toxic side effects of chemotherapy and radiation therapy and possibly increase the effectiveness of some chemotherapy drugs. However, the authors also caution that L-glutamine may stimulate the growth of some tumors.

In a more recent study (published in the journal Colorectal Disease in 2007), researchers found that L-glutamine supplementation decreased post-operative complications and reduced the duration of hospital stay among patients undergoing colorectal surgery for cancer. The study involved 109 patients with colorectal cancer.

Uses For L-Glutamine

L-glutamine supplements are purported to enhance exercise performance, as well as help with the following health conditions:

Additionally, L-glutamine is used to protect against the adverse effects of certain medical treatments (such as chemotherapy). L-glutamine is also said to help restore health in people who have experienced traumatic injuries or undergone surgery.


Although L-glutamine is generally considered safe, there's some concern that using L-glutamine supplements in combination with certain medications (including chemotherapy drugs and anti-seizure medications) may produce harmful effects.

Additionally, taking L-glutamine may be harmful to people with certain health conditions, such as severe liver disease, mania, and epilepsy.

Given these safety concerns, it's important to seek medical advice prior to using L-glutamine supplements.

Sources of L-Glutamine

Food sources of L-glutamine include:

  • barley
  • beef
  • cabbage
  • corn
  • cottage cheese
  • egg whites
  • milk
  • peanuts
  • pork
  • poultry
  • raw parsley
  • raw spinach
  • soy
  • yogurt

Where to Find L-Glutamine Supplements

Available for purchase online, L-glutamine supplements are sold in many natural-food stores and in stores specializing in dietary supplements.


Gleeson M. "Dosing and efficacy of glutamine supplementation in human exercise and sport training." J Nutr. 2008 Oct;138(10):2045S-2049S.

Haub MD, Potteiger JA, Nau KL, Webster MJ, Zebas CJ. "Acute L-glutamine ingestion does not improve maximal effort exercise." J Sports Med Phys Fitness. 1998 Sep;38(3):240-4.

Miller AL. "Therapeutic considerations of L-glutamine: a review of the literature." Altern Med Rev. 1999 Aug;4(4):239-48.

Oguz M, Kerem M, Bedirli A, Mentes BB, Sakrak O, Salman B, Bostanci H. "L-alanin-L-glutamine supplementation improves the outcome after colorectal surgery for cancer." Colorectal Dis. 2007 Jul;9(6):515-20.

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