L-Glutamine Side Effects

Glutamine or L-glutamine is a semi-essential amino acid, which means the body can produce appropriate amounts of it, but an individual still needs to consume food rich in it.

a beijing cabbage on a plate

Amino acids are one of the critical elements that help buildup and synthesize protein. There are approximately 21 of them, and one of which is glutamine. So, what does this specific amino acid do in the body? Also, while it can be found in food, supplemental glutamine is also readily available, but what are the L-glutamine side effects? Learn this and more here.

What is L-Glutamine?

Glutamine or L-glutamine is a semi-essential amino acid, which means the body can produce appropriate amounts of it, but an individual still needs to consume food rich in it. There are two varieties of L-glutamine; the first being the free form of L-glutamine which must be consumed along with a well-balanced meal.

The other form is known as trans-alanyl-glutamine or TAG. It is combined with one more amino acid, which makes it a better variation than the free form L-glutamine. This can be taken without food. 


L-glutamine is useful for numerous medical conditions. These include the following.

1. Burns

L-glutamine is administered via IV or a feeding tube. It improves wound healing and reduces infections in individuals with burns. Thus, it shortens a patient’s stay at the hospital.

2. Weight Loss Treatment

In individuals with HIV, L-glutamine is said to be an effective treatment for weight loss as well as a treatment for intestinal disorders. Approximately 40 grams of the amino acid each day helps a patient absorb nutrients from food plus help them gain the needed weight.

3. Surgery

L-glutamine administered through IV helps reduce complications and improve immune function, especially after a major surgical procedure.


Aside from its uses in the hospital setting, numerous individuals consume L-glutamine for its wealth of benefits for their health. Some of the benefits are as follows.

1. Improves Diabetes and Burns Fat

Glutamine supplementation increases HGH levels by approximately 400 percent which, in turn, increases the after-burn effect and metabolic rate. This results in weight loss and the buildup of lean muscle mass. Apart from the after-burn effect, L-glutamine stabilizes blood glucose and suppresses insulin levels, which results in balanced blood glucose as well as healthy insulin sensitivity.

2. Improves Digestive Health

For individuals suffering from gastrointestinal disorders like ulcerative colitis, irritable bowel syndrome (IBS), Crohn’s disease, diverticulitis, or leaky gut, L-glutamine supplementation is an effective treatment since it helps rebuild and repair the intestines. Moreover, the amino acid reduces inflammation in the intestines and hastens the recovery from food sensitivity.

3. Heals Ulcers and Leaky Gut

Based on clinical trials, glutamine aids in healing a leaky gut. Supplementation of the amino acid lessened permeability of the intestines. It also protects the stomach and intestines from damage as well as heals stomach ulcers. The amino acid serves as an alternative to prescription antibiotics usually prescribed for stomach ulcers.

4. Decreases Muscle Wasting and Promotes Muscle Growth

L-glutamine is effective in building muscle, improving recovery, boosting metabolism, and increasing athletic performance. Studies claim that the amino acid improves muscle hydration which, in turn, makes it faster and easier for the muscles to recover quickly from an intense workout. This is why supplemental glutamine is an essential part of the bodybuilding industry.

5. Supports Detoxification and Improves Immune Function

The leading role of glutamine is detoxification by removing excessive levels of ammonia in the body. Furthermore, it converts excess ammonia into urea, amino sugars, and other amino acids. It also boosts immune system function by increasing the number of T-helper cells.

6. Enhances Brain Health

The amino acid glutamine serves as the precursor to glutamate, a neurotransmitter in the brain. Thus, glutamine is essential for brain health because disruption to the cycle of glutamine-glutamate may likely lead to brain disorders such as anxiety, schizophrenia, depression, bipolar disorder, epilepsy, alcohol addiction, and Reye’s Syndrome. Other than its effect on brain health, glutamine stalls the aging of the brain.

7. Improves Diarrhea and IBS

Glutamine balances the production of mucus which leads to healthy movement in the bowels. Thus, it is an effective treatment for diarrhea and IBS.


As mentioned above, glutamine is a semi-essential amino acid. So, while the body can produce adequate amounts of the amino acid, an individual still needs to include glutamine-rich food in the diet. However, a supplemental form is also available. Food containing the richest amount of glutamine are listed below.

  • Turkey
  • Venison
  • Salmon
  • Broccoli Rabe
  • Asparagus
  • Cottage Cheese
  • Chinese Cabbage
  • Spirulina
  • Grass-Fed Beef
  • Bone Broth


For supplemental glutamine, the recommended dosage is 2 to 5 grams taken two times a day. However, the amount is raised to 10 grams each day if you are a power athlete who undergoes intense training. Take note to supplement glutamine with B vitamins, specifically vitamin B12 as it controls the buildup of the amino acid in the body.

On the other hand, a doctor is likely to recommend varying doses for a specific treatment. In the treatment of mouth sores caused by chemotherapy, glutamine suspension of around 4 grams is given. It should be swished and swallowed every four hours, which starts at the first dose of chemotherapy. The treatment must continue until the symptoms of mouth soreness subside or when the patient is discharged from the hospital.

Individuals with IBS, however, are recommended to take 5 grams which is taken six times a day. The maximum dose is approximately 30 grams daily. Nonetheless, the treatment may vary depending on a patient’s case and the recommendation of the primary physician.

Side Effects

L-glutamine supplementation is safe but taking an excessive amount is likely to cause side effects – much like other supplements. Some side effects that users claim to experience include hives, joint pain, nausea, and vomiting. If any of these signs appear, then it is best to discontinue the supplement and seek immediate medical aid.

Before taking supplements, it is highly advised to speak with your primary caregiver. The appropriate dosage will be prescribed once a thorough medical history is made. Furthermore, the supplement is ill-advised for pregnant and breastfeeding women, especially if it has not been approved for use by a doctor.

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