L-Glutamine Benefits, Side Effects, Dosage and Foods

Have you heard about the incredible health benefits of L-glutamine? First used in powder form by people in the fitness industry (including bodybuilders) who were looking to preserve muscle tissue, L-glutamine (also simply called glutamine) is an amino acid that is a building block of protein and needed by your body in large amounts. 

The most common original uses of glutamine powder were to meet the following goals: to lose weight fast, burn fat and help build muscle.

While that remains the case, science now shows that glutamine benefits are abundant. It also promotes digestive and brain health, boosts athletic performance — plus it’s helpful in treating intestinal issues and leaky gut.

In fact, it is one of our top three most recommended supplements overall for treating leaky gut and/or building a lean body. Let’s find out why.

What Is Glutamine?

With the chemical formula C₅H₁₀N₂O₃, glutamine is one of 20 naturally occurring amino acids found in protein foods. It’s also the most abundant amino acid in the bloodstream. It makes up 30 percent to 35 percent of the amino acid nitrogen in your blood.

It’s known as a conditional essential amino acid.

What does “conditional essential amino acid” mean? It means that your body can make some on its own but uses it in large amounts.

It also becomes essential when an individual faces disease or specifically muscle wasting. This can happen in the course of certain diseases or even physical trauma.

Additionally, it’s a conditionally essential nutrient during certain catabolic states, including after bone marrow transplantation.

Amazingly, around 60 percent of your skeletal muscle is made up of glutamine – and supplementing with this amino acid can aid protein synthesis and help naturally balance your pH levels.

Food Sources

Found in both animal and plant proteins (including in high levels in both casein and whey protein), glutamine is also available in supplement form and widely popular in the fitness community and beyond.

Glutamine can be found in animal proteins, such as meats and dairy, along with plant-based protein sources, such as beans, raw spinach, parsley and red cabbage. It’s worth noting, though, that animal proteins tend to provide amino acids that are more digestible than plant proteins.

Studies estimate that most people probably consume between three and six grams of glutamine from their daily diets.

The foods with the most L-glutamine benefits include:

1. Eggs
2. Tofu
3. Milk
4. Bone broth
5. Grass-fed beef
6. Spirulina
7. Chinese cabbage
8. Cottage cheese
9. Asparagus
10. Broccoli rabe
11. Wild-caught fish (cod and salmon)
12. Venison
13. Turkey
14. Corn
15. Rice

To obtain a healthy amount, a general recommendation is to consume at least three servings of these L-glutamine-rich foods daily.

L-Glutamine Benefits

What are the benefits of taking glutamine? New research now shows that L-glutamine benefits the body in the following ways:

1. Improves Gastrointestinal and Immune Health

L-glutamine benefits your overall health by supporting gut function and digestive processes. It can be beneficial if you have a digestive condition, such as:

• irritable bowel syndrome (IBS)
• an inflammatory bowel disease like Crohn’s disease
• ulcerative colitis
• diverticulosis
• diverticulitis
• leaky gut or any of the issues associated with leaky gut (like joint pain, rosacea or any type of autoimmune response)

It’s worth noting that the man famous for discovering the Krebs cycle in the body (also known as the “citric acid cycle“) was the first person to recommend taking L-glutamine for gut-related issues. That’s because Sir Hans Adolf Krebs — a German-born British biochemist who received (with Fritz Lipmann) the 1953 Nobel Prize for Physiology — found that it helped improve a healthy gut-related immune response. Additional research supports this finding.

For example, a study published in the journal of Clinical Immunology found that L-glutamine normalizes the effects of the Th3 immune response that stimulates inflammatory cytokines. The effects of L-glutamine in these studies show that it reduces intestinal inflammation and can help people recover from food sensitivities.

It’s also known to play an important role in maintaining healthy gut microbiota and immunity. It seems helpful for reducing intestinal colonization and bacterial overgrowth of pathogens. This may reduce the risk for widespread issues ranging from constipation to weight gain.

A 2018 article published in Nutrients also states that “in vitro and in vivo studies have determined that glutamine is an essential nutrient for lymphocyte proliferation and cytokine production, macrophage phagocytic plus secretory activities, and neutrophil bacterial killing. ” In fact, glutamine is currently part of clinical nutrition supplementation recommended for immune-suppressed individuals.

2. Can Help Treat Leaky Gut and Ulcers

There are millions of people struggling with a condition called leaky gut syndrome. It is essentially the main cause of autoimmune disease today.

Leaky gut  can contribute to thyroid issues like Hashimoto’s disease, along with arthritis, skin issues like psoriasis and other serious health concerns.

Because glutamine is the major fuel source for cells of the small intestine, it has been shown to support intestinal health and help treat leaky gut in clinical studies.

A study published in the medical journal Lancet referenced above examined 20 hospital patients and found that supplementing with L-glutamine decreased intestinal permeability. An animal study published in the British Journal of Surgery found that L-glutamine benefits ulcerative colitis and inflammatory bowel disease.

It also shows promise for treating ulcers by providing protection from further damage. Plus, it offers a healthier, natural alternative to antibiotics for the treatment of stomach ulcers.

If you’re unsure if you suffer from leaky gut, this leaky gut test can help. If, indeed, you appear to have leaky gut, L-glutamine is the No. 1 amino acid you need to help heal and repair it. 

3. Supports Brain Health

A precursor to the neurotransmitter glutamate in your brain, glutamine is key to boosting your brain health. Why? A disruption of the glutamine-glutamate cycle can result in all kinds of brain problems, including:

• Reye’s syndrome
• epilepsy
• bipolar disorder
• schizophrenia
• anxiety
• depression
• alcohol addiction

Glutamine can also help stall brain aging. Mitochondrial dysfunction causes abnormal increases in the neurotransmitter glutamate and, again, puts the brain at risk for developing the above problems.

A study conducted at the New York University School of Medicine showed that even mild traumatic brain injury caused brain atrophy, and most of this damage was due to the disrupted glutamine-glutamate cycle and an abnormal increase in glutamate levels.

4. May Improve IBS Symptoms and Diarrhea

Glutamine helps improve IBS and diarrhea by balancing mucus production. This results in healthier bowel movements.

If you have Hashimoto’s or an underactive thyroid, consider making it a part of your hypothyroidism diet. The same goes for anyone who suffers from IBS symptoms like constant diarrhea or ulcerations.

5. Promotes Muscle Growth and Decreases Muscle Wasting

Whether your goal is to increase athletic performance, boost metabolism, improve recovery or even build muscle, research shows that L-glutamine can significantly aid your efforts. During an intense workout, your body becomes stressed, and your muscles and tendons require more glutamine than the amount supplied by a normal diet.

After an intense workout, the levels of cellular glutamine can drop by 50 percent and plasma levels by 30 percent. This muscle-wasting state is a gateway for the body to use your muscle for energy rather than carbohydrates, but glutamine can help prevent this from happening.

Supplementing with L-glutamine allows your muscles to fight and push a bit further. This boosts your strength and helps repair your skeletal muscles.

A study found that glutamine supplementation makes it possible to recover quicker from intense weight training sessions because it improves muscle hydration. This aids the muscle recovery process and reduces recovery time for wounds and burns.

It’s why glutamine supplementation is not only common for bodybuilders in the bodybuilding industry, but in nearly every athletic pursuit these days.

6. May Improve Athletic Performance and Recovery from Endurance Exercise

One of L-glutamine’s main roles in the body is to support detoxification by cleansing the body from high levels of ammonia. It acts as a buffer and converts excess ammonia into other amino acids, amino sugars and urea.

Doing approximately one hour of exercise can cause a 40 percent reduction of glutamine in the body. It can also cause suppressed immune function. This has a negative impact on your resistance training and may lead to overtraining syndrome.

L-glutamine benefits long distance athletes as well by boosting the immune system (T-helper cells). Animal studies have indicated that this increase in T-helper cells may reduce the “stresses” associated with overtraining syndrome.

However, not every study has found that it necessarily boosts performance. One 2019 review that included data from 55 studies observed that glutamine improved some fatigue markers, such as increased glycogen synthesis and reduced ammonia accumulation, but this intervention did not always increase physical performance.

7. Supports Metabolic and Heart Health

Research has indicated that human growth hormone (HGH) levels go up nearly 400 percent after glutamine supplementation. This hormonal response leads to an increase in resting metabolic rate and improves the afterburn effect or EPOC post-exercise.

This afterburn effect is essential for burning fat, weight loss and building lean muscle mass.

Is glutamine good for weight loss? There’s evidence suggesting that it helps burn fat and build lean muscle mass by suppressing insulin levels and stabilizing blood glucose. This enables the body to use less muscle mass to maintain blood sugar and insulin sensitivity in the cells.

In fact, six weeks of supplementation with 30 grams per day of glutamine powder “markedly improved some cardiovascular risk factors, as well as body composition, in patients with type 2 diabetes” in one study. For this reason, L-glutamine benefits diabetics and those with sugar and carb cravings as well.

Emerging evidence also indicates that l-glutamine plays a fundamental role in cardiovascular health by serving as a substrate for the synthesis of DNA, ATP, proteins and lipids. Additionally it seems to have potent antioxidant and anti-inflammatory effects that can reduce risk factors for cardiovascular disease, such as:

• hypertension
• hyperlipidemia
• glucose intolerance
• obesity
• diabetes

Related: Do Digestive Enzymes Prevent Nutrient Deficiencies & Boost Gut Health?

Deficiency

L-glutamine is synthesized by the body from glutamic acid or glutamate. If the body is unable to produce enough it needs to get it directly from your diet.

It’s estimated that 70 million Americans now suffer from digestive diseases, so it’s apparent that our diets severely lack certain nutrients that support the digestive tract. While L-glutamine is synthesized by the body from glutamic acid or glutamate, sometimes the body is unable to produce enough — plus the majority of people don’t seem to get enough L-glutamine from their food alone if they eat low-protein diets.

Some reasons that you may run low in glutamine include:

• Eating a low-protein diet
• Undergoing lots of stress
• Exercising intensely
• Battling infections and illnesses
• Undergoing treatments, including radiotherapy and chemotherapy
• Having an immune disorder
• Having a chronic gastrointestinal disorder

This is why supplementing your diet with it is an excellent way to boost your immune system and improve your ability to fight infection and diseases.

Glutamine has even become a common supplement for critically ill patients. According to a study published in the medical journal Critical Care, glutamine dipeptide-supplemented parenteral nutrition “continues to be associated with a significant reduction in hospital mortality and hospital length of stay.”

Supplements and Dosage

Types of L-Glutamine

There are two forms of L-glutamine. You can get regular L-glutamine in what’s called its free form, and it should be taken with food ideally for proper absorption by the body. 

The other type is called trans-alanyl-glutamine or alanyl-L-glutamine. It’s an amino acid attached to another amino acid. That basically means you can digest it much better.

Unlike free-form glutamine powder, you can take it on an empty stomach.

Both forms are best taken right after or right before workouts — with your small meals right before or after workouts for it to support your metabolism and weight loss as well as for muscle building, recovery and preservation.

Dosage Recommendations

Typically, the best dosage is an ingestion between two to five grams taken twice daily and up to 10 grams twice daily for serious power athletes. 

When should you take glutamine? Replenishing glutamine levels after an intense session could take up to five days, so it is important to take it on a regular basis if you do intense exercise.

Some bodybuilders say that glutamine works best when combined with certain brained chain amino acids (BCAAs), especially leucine. Others consume it post-workout with creatine in order to try to improve muscle recovery and restore the body’s energy stores.

Risks and Side Effects

Overall, glutamine seems safe to consume in moderate amounts, especially if taken short term. There seems to be low risk for side effects when taken in doses up to 20 to 30 grams per day, which are considered higher doses but have been used safely in some studies short term.

Although the effects of excess glutamine rarely cause problems, if you take oral glutamine long term, it’s a good idea to also supplement with B vitamins. This especially applies to vitamin B12, which controls glutamine buildup in the body.

Who should not take glutamine?

Anyone with a history of kidney disease, liver disease, Reye’s syndrome or cancer should not take this supplement unless working with a doctor, since these conditions can affect how amino acids are absorbed.

If you’re battling cancer and/or undergoing cancer treatments, always speak with your doctor about which supplements may or may not be helpful.

In rare cases, allergic reactions to this supplement have been reported. Stop taking it right away if you experience symptoms like nausea, vomiting, hives, dizziness or pain.

Conclusion

• Glutamine is one of 20 naturally occurring amino acids found in protein foods. It’s the most abundant amino acid in the bloodstream.
• It’s known as a conditional essential amino acid because your body uses it in large amounts. This means you need to keep replenishing your supply. 
• Research suggests that are several important l-glutamine benefits for muscle mass, digestion and brain health. Galera SC, Fechine FV, Teixeira MJ, Coelho ZC, de Vasconcelos RC, de Vasconcelos PRThe safety of oral use of L-glutamine in middle-aged and elderly individualsNutrition.(2010 Apr)

  Useful properties of glutamine and recommendations for use. ✔️Blog SAYYES

  Glutamine is one of the most important amino acids in the human body, as it is used to support many functions, including protein building blocks, immune system function, and gastrointestinal function. However, this substance is of greatest importance for the normalization of bowel function.

  This amino acid is naturally generated in the human body, but can also be obtained from food. But in some cases, glutamine from natural foods may not be enough to meet the needs of the body. In such cases, experts recommend the use of specialized nutritional supplements.

  In this article, we will look at what glutamine is, its positive effect on the human body, as well as the rules of administration and possible side effects.

  The amino acid glutamine, like a number of other amino acids in the human body, is a multifunctional molecule. The main task of this substance is to generate building blocks for protein, which in turn are used to transport nutrients to internal organs, muscle fibers and skin, as well as to fight viral diseases and harmful bacteria.

  Like a number of other amino acids, glutamine occurs in two forms, D-glutamine and L-glutamine. These forms have some similarities, but differ from each other in molecular arrangement.

  L-glutamine is found in natural products and specialized food supplements. According to scientists, it is this form of amino acid that is used by the human body to generate proteins, while D-glutamine is almost useless.

  A useful form of this amino acid can be produced naturally in the body. Moreover, it is worth paying attention to the fact that L-glutamine is the most abundant amino acid found in human blood.

  In some cases, the human body is not able to generate glutamine in sufficient quantities, which implies the need for this amino acid from external sources, especially during illness and recovery after injury. That is why many scientists call L-glutamine a conditionally essential amino acid.

  In addition to all of the above, this amino acid is necessary for the normal functioning of the intestines and the immune system.

  Natural sources of glutamine

  As mentioned earlier, glutamine can be obtained not only from supplements, but also from natural products. So, the standard daily diet of an average person contains from 3 to 6 grams of this amino acid, depending on the products used. However, it is worth noting that the greatest amount of this substance is found in foods high in protein.

  Although the highest concentration of glutamine is found in animal products, this amino acid can also be found in high protein plant foods.

  Recently, scientists conducted a study in which they determined the percentage of glutamine in a number of products. The results were as follows:

  • eggs – 4.4 percent;
  • beef – 4.8 percent;
  • skimmed milk – 8. 1 percent;
  • tofu – 9.1 percent;
  • white rice, 11.3 percent;
  • corn – 16.2 percent.

  Although plant sources have the highest percentage of glutamine, their protein content is considered negligible. Based on this, the researchers concluded that the best way to obtain this amino acid is to include beef in the diet.

  Due to the fact that glutamine is an integral part of protein, almost any food high in it will contain this amino acid. In this regard, experts recommend that when compiling a diet, pay attention to foods high in protein, which will provide the body with the necessary amount of glutamine.

  Importance of glutamine for the immune system

  One of the most important functions of glutamine is to support the functioning of the immune system. This amino acid is the most significant source of fuel for cells that provide strong immunity, namely for leukocytes and some intestinal cells. It should be noted that the level of glutamine in the blood can decrease due to injuries, operations and burns.

  Under the condition of an acute need for this amino acid, the human body is able to independently use the reserves of protein stored in the body to release it, which is manifested in a decrease in muscle mass.

  Lack of glutamine can also impair the functioning of the immune system. Therefore, high-protein supplements or diets that involve eating protein foods are prescribed for people recovering from injuries and burns.

  During research, scientists have also found that high glutamine supplements can improve well-being, reduce infections in the body, and reduce hospital stays after surgery. This amino acid has also been found to reduce the risk of death and the need for medications in critically ill people.

  Animal experiments have shown that glutamine can also improve the functioning of the immune system and speed up the recovery of individuals infected with viruses or harmful bacteria.

  However, despite all of the above, scientists have found no evidence that glutamine supplementation can in any way improve the condition of completely healthy people.

  Effects of Glutamine on Gut Health

  The immune-boosting benefits of glutamine stem from its effects on the gut, one of the most important components of the immune system.

  The human intestine contains a huge number of cells and bacteria responsible for the functioning of the immune system and for well-being in general. According to scientists, it is glutamine that is the main source of energy for these cells.

  Glutamine helps to maintain a barrier between the intestines and other internal organs, thereby protecting them from the penetration of harmful substances, toxins and pathogenic bacteria into the blood. This substance is also necessary for the normalization of growth and strengthening of intestinal cells.

  By improving the functioning of the intestines, glutamine can have a positive effect on improving the functioning of the immune system.

  The effect of glutamine on muscle growth

  Due to the fact that this amino acid is used by the human body to generate protein, scientists began to study its effect on the increase in muscle mass and the body of athletes.

  So, during one of the experiments involving two groups, the first was given supplements of glutamine, and the second – a placebo. After completion of the study, both groups showed an increase in strength and muscle volume. However, no significant differences were observed between the participants of both groups.

  In additional research in this area, scientists have found that this amino acid has no effect on performance levels and increase in muscle mass.

  However, despite this, some studies have shown that adding glutamine to the diet can speed up the recovery process after intense training using heavy weights. Also during this experiment, it was found that this amino acid, when used in combination with carbohydrates, can reduce fatigue during long-term exercise, such as a 2-hour run.

  In other studies, scientists have not found any additional benefits for athletes. Thus, the researchers concluded that the addition of glutamine to the diet of athletes does not affect the increase in muscle mass.

  However, it is worth noting that many athletes consume a large amount of protein per day, because of which their body receives the necessary amount of glutamine daily, which eliminates the need for supplements with a high content of this amino acid.

  Glutamine recommendations and side effects

  Due to the fact that the human body is able to generate glutamine on its own, and can also get it from natural foods, the likelihood of an overdose of this amino acid is extremely low, and its use in the recommended amount is absolutely safe.

  According to the results of studies, the standard diet of an average person contains from 3 to 6 grams of glutamine. However, during the studies, completely different amounts of this amino acid were used, which ranged from 5 to 45 grams per day. It is important to note that even at the highest dosages of this substance, the participants in the experiments did not experience any side effects.

  According to scientists, the use of glutamine is absolutely safe provided that it is consumed over a short period of time. However, some scientists have expressed concern about the use of this substance over a long period of time, despite the fact that long-term studies have also not revealed any side effects. Despite this, scientists need to do more research to identify possible side effects of regular intake of this amino acid.

  Most likely, taking glutamine supplements on a high protein diet will not have any positive effect on the body. However, when following a vegetarian diet, this supplement is necessary.

  Glutamine supplementation is recommended to start with small amounts – from 5 grams per day.

  Conclusion

  Glutamine is an amino acid that is naturally generated in the human body. This element exists in several forms – L-glutamine and D-glutamine.

  The active and most beneficial form of this substance is L-glutamine, which is produced by the human body and can be found in some high protein foods. According to statistics, the standard diet of an average person contains from 3 to 6 grams of this amino acid.

  Among the beneficial properties of glutamine, researchers highlight:

  • improved bowel condition;
  • strengthening the immune system;
  • acceleration of the recovery process after injuries;
  • reduction in the duration of illnesses.

  This amino acid is often used as a sports supplement, but many studies show that it is not able to have a positive effect on the process of increasing muscle mass.

  This supplement is completely safe in the short term, but more research is needed to determine its effects on the body in the long term.

  Research links

  1. What are proteins and what do they do?

  https://ghr.nlm.nih.gov/primer/howgeneswork/protein

  2. Protein design with L- and D-alpha-amino acid structures as the alphabet.

  https://www.ncbi.nlm.nih.gov/pubmed/18642934

  3. On the origin of terrestrial homochirality for nucleosides and amino acids.

  https://www. ncbi.nlm.nih.gov/pubmed/19478058

  Glutamine description, functions, benefits for athletes

  Glutamine is a conditionally essential amino acid that is present in human blood and muscles. Glutamine plays an important role in nitrogen metabolism and protein synthesis, supports important functions of the brain, kidneys, intestines, lungs, and immune system. This amino acid is widely used in bodybuilding as a sports supplement with a wide spectrum of action. In medicine, glutamine is sometimes used as a means to regulate the metabolic processes of the body, treat the gastrointestinal system, prevent psychological disorders, and treat certain brain diseases.

  Many amino acids are precursors for glutamine synthesis, in particular the branched chain amino acids (BCAAs). This highlights the importance of consuming amino acids and confirms why it is so important to eat quality foods rich in proteins from which these amino acids are actually extracted. However, glutamine, which is used as an L-form amino acid, plays an important role in the muscle building process. Back in the mid-1980s, scientists discovered a relationship between glutamine levels and the rate of muscle protein synthesis.
  The higher the level of free glutamine in the blood, the faster the growth of muscle cells.

  Although glutamine is produced by the body, under conditions of prolonged hard training, the body needs much more glutamine to meet the huge consumption of this substance.

  Glutamine, which is used as an L-form amino acid, plays an important role in the muscle building process. The higher the level of free glutamine in the blood, the faster the growth of muscle cells.

  The effects of glutamine are as follows. Glutamine takes part in the synthesis of muscle proteins and, like glucose, serves as a source of energy. By inhibiting the secretion of cartisol , it prevents muscle catabolism. A daily intake of 5 g of glutamine helps to raise the level of growth hormone by four times. Helps speed up the recovery process after training, prevents the development of overtraining, strengthens the immune system.
  Glutamine also acts as a powerful ammonia scavenger. Ammonia is highly toxic to muscle cells. Ammonia is used to make glutamine and deliver it to the blood. It is then transferred to other tissues to be used as fuel, especially in the cells of the immune system. Glutamine is directly involved in the regulation of protein synthesis and has a strong influence on anabolism. If human physiology is affected by any external factors, for example: stress, mental work, hard physical work, the body’s needs for glutamine can increase dramatically. One of these effects in the form of stress on the human body is long-term physical training with heavy weights. During training, the body’s need for glutamine increases in proportion to the applied stress. As a result of this stress, the level of glutamine in the body is markedly reduced. To replenish these reserves, the muscles begin to secrete glutamine from the reserve into the blood. Therefore, glutamine is one of the main amino acids in the body. Hard training also leads to the production of catabolic hormones such as corticosteroids. These glucocorticoids also deplete muscle stores of glutamine. An excessive concentration of corticosteroids in the blood leads to the fact that glutamine continues to be released into the blood even after exercise has ceased and the body no longer needs glutamine in large quantities. As a result, glutamine stores are significantly depleted.

  How to take glutamine?

  The recommended dose for taking glutamine is 4-8 g per day. This dose should be divided into two doses: one taken immediately after the end of the workout, and the second taken before bedtime on an empty stomach. Reception after training is necessary in order to saturate the body exhausted by training, suppress catabolism and start the growth of muscle tissue. Taking glutamine before bed increases the production of growth hormone, which is produced at night.