L-Glutamine: Health Benefits, Dosage, Side Effects & Supplements


L-Glutamine is the most common amino acid in the body and is manufactured by the human body. It helps maintain muscle, ligaments, cartilage and skin.

Studies have shown L-Glutamine can help fight oxidative stress and chronic fatigue by modulating inflammation, cortisol levels and insulin resistance.

Glutamine is an amino acid, one of the building blocks of protein. It is synthesised in the body from the essential amino acid lysine and ammonia and can be found in a wide array of foods. Glutamine has been shown to be helpful for many different health conditions. It may help with chronic fatigue syndrome, depression, and various digestive conditions.

There are many benefits to glutamine and this article aims to show you some of the most important ones. It also discusses how safe glutamine supplements can be in certain circumstances.

What is Glutamine: A Brief Overview

What is Glutamine
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Glutamine is an important amino acid required to serve many critical roles in the body. This conditionally essential amino acid, being the most abundant, is found in the liver, skeletal muscles, plasma, lungs, intestines and brain.  

The body can produce glutamine. Its concentration and availability depend on the balance between its synthesis, release and uptake by organs and tissues in the whole body. Glutamine requirement increases in our body under conditions like intense physical activities, surgery, or infections. Under such cases, it becomes essential to supply glutamine externally to meet the demands. 

The low glutamine concentration affects the whole body because many metabolic pathways and mechanisms dependent on glutamine availability are affected, resulting in low immunity levels.

Glutamine exists in two forms: L-Glutamine present in food sources and dietary supplements and D-Glutamine, which is biologically unavailable. Eggs, meat, dairy products and tofu are some glutamine-rich foods. Glutamine supplements are available in powder and capsules form that is pretty popular among bodybuilders and fitness lovers.

As mentioned above, glutamine is involved in many bodily processes, and the next section will discuss why you should not underestimate glutamine. 

Why do we Need Glutamine?

Why do we Need Glutamine
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To understand why glutamine is necessary, let’s take a closer look at its benefits and uses.

1. Strengthen immune health

Studies indicate that glutamine is an essential modulator of our immune cells – macrophages and lymphocytes. During infections, the utilisation of glutamine by the immune cells rises; hence the external supply of glutamine becomes imperative to maintain the total plasma glutamine concentration. 

Low levels may increase the risk of subsequent infections. In addition, glutamine has been shown to suppress the levels of certain inflammatory compounds. Therefore, make sure that you don’t have glutamine deficiency if you want your immune system to run strongly.

2. Amplify athletic performance

If you are into intense workouts or any endurance sport, glutamine supplementation might benefit you. Athletes prefer taking glutamine because of its potential to boost the recovery process. This amino acid has been shown to ease muscle soreness and speed up recovery.

A study published in the Journal of Human Sport and Exercise observed that glutamine supplementation improved male athletes’ exercise performance during an eight-week resistance training program. Another study published under the British Journal of Sports Medicine noticed that L-glutamine supplementation weakens DOMS effects when ingested for four weeks.  

3. Promote muscle growth

Glutamine assists in the transportation of nitrogen in the body required for new muscle synthesis and maintaining a positive nitrogen balance. Also, glutamine supports the secretion of the Human Growth Hormone (HGH), leading to lean muscle mass gain and fat loss.  

4. Healthy gut

Lack of glutamine can affect intestinal health significantly. People suffering from severe gut issues like leaky gut or Inflammatory Bowel Syndrome (IBS) can go for L-glutamine supplements to improve the symptoms and gut functioning. 

Glutamine serves as fuel for synthesising the gut lining that acts as a protective barrier between the small intestine and external blood and prevents the entry of harmful toxins and pathogens. Go for Nutrabay Pure L-Glutamine, the best glutamine supplement for leaky gut. 

5. Support rehydration

Muscle cramp is a common issue faced during intense workouts due to sweating and sodium excretion. Some studies also indicate that glutamine might help prevent sodium loss, dehydration and muscle cramps when consumed during a workout or post-workout in the presence of glucose. 

When to take glutamine?

When to take glutamine
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Glutamine supplements come in various forms, including powder, tablets, and capsules. For beginners, it is recommended to take 5 grams of L-glutamine tablets or powder before or after a workout.

However, professional athletes may require higher doses of glutamine, with up to 30 grams per day divided into three doses of 10 grams each before, during, and after exercise.

It’s important to note that pregnant or lactating women and individuals with pre-existing medical conditions should consult their healthcare provider before starting any glutamine supplement regimen.

Are there any side effects of taking glutamine?

side effects of taking glutamine
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There is no need to worry about any negative effects when taking glutamine through oral supplementation for an extended period. 

Several studies have been conducted to evaluate the safety of long-term use of glutamine, and they have consistently shown that taking up to 45 grams per day for six weeks did not cause any adverse reactions or glutamine side effects. Therefore, it is safe to say that glutamine is a well-tolerated supplement when taken within the recommended dosage range. 1

What are some best glutamine supplements?

best glutamine supplements
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If you’re considering taking an oral glutamine supplement, it’s recommended that you choose one that contains L-glutamine. Here are some of the top glutamine supplements to consider:

Nutrabay Pure L-Glutamine

1. Nutrabay Pure L-Glutamine

It is the best L-glutamine oral powder as it contains pure glutamine powder from a vegetarian source without any added artificial additives. The unflavoured form provides the flexibility to add it in water, juice or your favourite protein shake. Nutrabay Pure L-Glutamine is the perfect option if you need a high-quality supplement in an affordable range.

MuscleBlaze L-Glutamine

2. MuscleBlaze L-Glutamine

It provides pure and unadulterated micronized glutamine with a faster absorption rate to speed up recovery and reduce catabolic state. The supplement is available in flavoured and unflavoured forms and free from harmful substances.

MuscleTech Glutamine

3. MuscleTech Glutamine

MuscleTech Platinum 100% Glutamine contains a 5 g dose of glutamine to rapidly replenish the glutamine used during training. It is tasteless, mixes instantly with any of your drinks and is a non-stimulant formula to use any time.

GNC Glutamine

4. GNC Glutamine

It is an excellent choice for fitness enthusiasts willing to maintain muscle glutamine levels. GNC Pro Performance L-Glutamine 5000mg is a gluten-free dietary supplement featuring micronized glutamine for muscle growth and fuel immune cells.

BigMuscles Glutamine

5. BigMuscles Glutamine

Looking for pharm grade glutamine for muscle growth and tissue repair, go for BigMuscles Nutrition Glutamine. Every serving provides you with 5 g of L-Glutamine to help gain lean muscle by keeping the cells hydrated during intense workouts and eliminating the risk of dehydration causing fatigue.

A Quick Recap

L-Glutamine: Health Benefits, Dosage, Side Effects & Supplements
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L-glutamine is a versatile amino acid with numerous health benefits. It plays an essential role in the immune system, gut health, and muscle recovery. The recommended daily dosage of glutamine varies depending on the individual’s age, weight, and health status. However, taking up to 45 grams per day for six weeks has been shown to be safe and well-tolerated in studies.

While L-glutamine supplementation is generally safe, some people may experience mild side effects such as nausea, stomach pain, or headache. It is always recommended to consult a healthcare professional before starting any new supplement, especially if you have a medical condition or are taking medication.

There are several forms of L-glutamine supplements available, including capsules, powders, and liquids. It’s essential to choose a reputable brand and follow the manufacturer’s instructions for dosage and administration.

Overall, L-glutamine can be a beneficial supplement for those looking to support their immune system, improve gut health, or enhance muscle recovery. With proper dosage and administration, it is safe and well-tolerated for most people. 

However, as with any supplement, it’s essential to do your research, consult a healthcare professional, and listen to your body to determine what works best for you.

When should I take l-glutamine?

You can take l-glutamine any time of the day. If using it to improve workouts and reduce the onset of fatigue, try using it 30 minutes prior to your workout, during your workout, and/or immediately following a strenuous workout.

Can I get enough l-glutamine from food?

Yes, you can get plenty of l-glutamine from your diet. Because l-glutamine is an amino acid, choosing high protein foods will help ensure you’re getting more than your fair share.

How long does it take glutamine to heal gut?

In fact, studies in both adults and children have demonstrated that supplementing with L-glutamine was able to help to tighten the gut lining in as little as 10 DAYS – a super important improvement for those of you experiencing leaky gut.01

Can I take L-glutamine and probiotics at the same time?

To achieve synergistic benefits in the treatment of intestinal injury following severe burns, glutamine and probiotics can be used together.

What happens if you take L-glutamine after eating?

Glutamine taken with food is more likely to join with other amino acids in the formation of muscle protein. If instead your purpose for taking glutamine is to increase the production of GABA, for its calming effects, you can use a lot less (1 to 4 grams per day), if you take it apart from food

Does L-glutamine help heal gut lining?

Your intestinal lining actually uses L-glutamine as fuel to create a strong surface for digestion and absorption. Supplementing with L-glutamine is the most effective treatment to heal the gut lining for those suffering from leaky gut, malabsorption, or inflammatory bowel disease (IBS, Crohn’s, Ulcerative colitis).

  1. Bowtell, J. L., Gelly, K., Jackman, M. L., Patel, A., Simeoni, M., & Rennie, M. J. (1999). Effect of oral glutamine on whole body carbohydrate storage during recovery from exhaustive exercise. Journal of Applied Physiology, 86(6), 1770-1777.[]
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