L-Glutamine is a conditionally essential amino acid — your body makes it on its own, but during illness, intense exercise, surgery, or chronic stress, demand outpaces supply and you need more from food or supplements.

How does L-Glutamine work?

The cells lining your gut (enterocytes) and your immune cells (especially lymphocytes and macrophages) run almost entirely on glutamine as fuel, so keeping levels topped up keeps both systems functioning well.

How much L-Glutamine should you take?

5-10 g per day for general gut health and immune support; 10-20 g per day for athletic recovery or clinical gut repair protocols. Clinical use (post-surgical, IBD) may go up to 30-40 g/day under medical supervision.

How long does L-Glutamine take to work?

Gut lining and craving effects often noticed within 1-2 weeks; athletic recovery benefits typically within 2-4 weeks of consistent daily use.

What are the side effects of L-Glutamine?

Reported side effects of L-Glutamine include mild bloating or gas at high doses, loose stools or mild nausea in sensitive individuals, headache occasionally reported, particularly when starting supplementation, theoretical ammonia accumulation at very high doses in people with liver or kidney disease and people with a…

What forms does L-Glutamine come in?

Powder is the most popular and practical form — it's unflavored, mixes easily into water or smoothies, and allows flexible dosing. Capsules and tablets are convenient for travel or precise dosing but can require taking several at once to reach therapeutic amounts.

Which foods are rich in L-Glutamine?

Foods rich in L-Glutamine include beef and lamb, eggs, cottage cheese and ricotta, chicken and turkey and raw cabbage and spinach.

L-Glutamine

Traditionally used for: Leaky gut / gut lining repair; Muscle recovery; Sugar and alcohol cravings. Widely used to support gut lining health.

Home

What is L-Glutamine? L-Glutamine is a non-essential amino acid that is found abundantly in the body. It is produced naturally by the body and is also obtained through the diet. L-Glutamine plays a crucial role in various bodily functions such as the immune system, digestive system, and brain function. How does it work? L-Glutamine works by aiding in the production of proteins that help repair and regenerate tissues in the body. It also helps to strengthen the immune system and promote healthy digestion. L-Glutamine has been used for medicinal purposes to treat a wide range of conditions such as gastrointestinal disorders, muscle wasting, and immune dysfunction. What are the active ingredients that are important for its medicinal properties? The active ingredient in L-Glutamine is the amino acid L-glutamine. What forms does it come in? L-Glutamine is available in various forms such as capsules, powder, and liquid. What can happen if I have an imbalance or deficiency? A deficiency of L-Glutamine can lead to muscle wasting, impaired immune function, and digestive issues. If you have an imbalance or deficiency, it is recommended to consult a healthcare professional to determine the appropriate course of treatment. When was it first used for medicinal purposes? L-Glutamine has been used for medicinal purposes for several decades, with early studies dating back to the 1980s.

Helps

What does L-Glutamine help with? L-Glutamine is an amino acid. Your body makes it, and you also get it from food such as meat, eggs and dairy. It is sold as a powder or capsule, often for gut health or for sport. IBS with loose, frequent stools Good evidence — clinical trials in people with diarrhoea-type IBS; sizes and doses not recorded in this file. In clinical trials, people with diarrhoea-type IBS took glutamine. They had fewer bowel movements, firmer stools and less gut discomfort. The trial sizes, doses and journals are not on file here. Evidence grade B · Traditional tier T0 Getting back on your feet after major surgery Early evidence — use in hospital clinical nutrition; no trial sizes on file. After major surgery, the body uses up its glutamine fast. That drop is well documented, and it can slow healing. Hospital feeding plans often add glutamine to support repair and cut infection risk, but no trial sizes are on file here. Evidence grade C · Traditional tier T0 Sore muscles after hard training Early evidence — early human exercise studies; no sizes or doses on file. Hard training lowers glutamine in blood and muscle. That much is well measured. In exercise studies, topping it back up may cut muscle breakdown and shorten soreness, though no trial sizes or doses are recorded here. Evidence grade C · Traditional tier T0 The immune dip after long, hard endurance sessions Evidence doesn't support this — studied in athletes, but no clear result on file. Hard endurance work is followed by a few hours of weaker immune defence. Some people call this the open window. Glutamine has been studied around training for this, and this file holds no clear result. Evidence grade D · Traditional tier T0 Crohn's disease and ulcerative colitis, as an extra support Evidence doesn't support this — hedged clinical reports only; no trial result on file. In these conditions the gut lining is damaged, and glutamine turnover runs high. Some clinicians add it to support lining repair. No trial result is on file, and it is not a swap for medical care. Evidence grade D · Traditional tier T0 Keeping your defences up during stress or illness Not yet tested in people — cell biology only; no human trial on file. It is well established that immune cells use glutamine as a main fuel. Blood levels fall during illness, heavy training and high stress. Whether taking it keeps those cells working better in people is not shown by any study on file. Evidence grade insufficient · Traditional tier T0 Leaky gut and a loose gut wall Not yet tested in people — established cell biology; no human study on file. Glutamine is well established as the main fuel for the cells lining your small intestine. That is general biology, not a trial of this supplement. This file holds no human study showing that taking it tightens the gut wall. Evidence grade insufficient · Traditional tier T0 Sugar and carb cravings Not yet tested in people — user reports only; no human trial on file. The brain can turn glutamine into glucose, which is basic biochemistry. Many people say their sugar cravings drop within 1 to 2 weeks , taking it with water between meals. Those are reports, not trial results. Evidence grade insufficient · Traditional tier T0 Alcohol cravings in early recovery Not yet tested in people — long use in recovery programs; no human trial on file. Recovery programs have used glutamine for years, mostly for alcohol. Users and practitioners report fewer cravings and steadier mood and energy in withdrawal. No human trial is on file, and it is used beside other care, not alone. Evidence grade insufficient · Traditional tier T0 What L-Glutamine has not been shown to do No study on file shows it seals or heals a leaky gut wall in people. No trial here shows it helps IBS with constipation; the trials were in the diarrhoea type. No human trial on file shows it stops drinking or treats alcohol addiction on its own. No result on file shows it prevents colds or infections in healthy

L-Glutamine

Quick Facts

What it is: L-Glutamine is the most abundant amino acid in the human body, serving as a key fuel source for gut cells, immune cells, and muscle tissue.
Main uses: Widely used to support gut lining health, speed muscle recovery, reduce sugar cravings, and maintain immune function during stress or illness.
Best for: Leaky gut / gut lining repair, Muscle recovery, Sugar and alcohol cravings
Active ingredients: L-Glutamine
Forms: powder, capsule, tablet, IV solution (clinical use)
Time to effect: Gut and craving benefits often noticed within 1-2 weeks; muscle recovery improvements typically within 2-4 weeks of consistent use.
Side effects: Generally very well tolerated at standard doses; high doses may cause mild digestive discomfort in some people.
Pregnancy & breastfeeding: Avoid unless your clinician advises otherwise.

Educational information, not medical advice — ask your doctor or midwife.

Track this remedy in the app

Track L-Glutamine with reminders and see your options for Gluten Sensitivity in the app.

What is L-Glutamine?

L-Glutamine is a non-essential amino acid that is found abundantly in the body. It is produced naturally by the body and is also obtained through the diet. L-Glutamine plays a crucial role in various bodily functions such as the immune system, digestive system, and brain function.

How does it work?

L-Glutamine works by aiding in the production of proteins that help repair and regenerate tissues in the body. It also helps to strengthen the immune system and promote healthy digestion. L-Glutamine has been used for medicinal purposes to treat a wide range of conditions such as gastrointestinal disorders, muscle wasting, and immune dysfunction.

What are the active ingredients that are important for its medicinal properties?

The active ingredient in L-Glutamine is the amino acid L-glutamine.

What forms does it come in?

L-Glutamine is available in various forms such as capsules, powder, and liquid.

What can happen if I have an imbalance or deficiency?

A deficiency of L-Glutamine can lead to muscle wasting, impaired immune function, and digestive issues. If you have an imbalance or deficiency, it is recommended to consult a healthcare professional to determine the appropriate course of treatment.

When was it first used for medicinal purposes?

L-Glutamine has been used for medicinal purposes for several decades, with early studies dating back to the 1980s.

If this is an emergency

Some reactions to L-Glutamine need urgent care. Call your local emergency number or go to an emergency department straight away — do not wait to see whether it passes.

Who should avoid L-Glutamine?

Do not take high doses if you have liver disease, unless your doctor is guiding you.
Do not take high doses if you have kidney disease, unless your doctor is guiding you.
Don't start it on your own if you have bipolar disorder or past mania.
Avoid doses above 15 g a day unless a doctor is watching you.
Avoid starting at a big dose, since gas, bloating and loose stools are more likely.
Stop taking it if you get bad nausea or loose stools that do not settle.
Do not take glutamine if you have seizures or take seizure drugs, unless your doctor agrees.
Never add it to a low-protein diet your doctor has ordered without asking them first.
Avoid it if you react badly to MSG (monosodium glutamate), a related food additive.
Don't take supplement doses while pregnant or breastfeeding unless your doctor approves.

When should you see a doctor?

Mild gas, loose stools or a headache in the first week is common. Drop back to a smaller dose and take it with food. If it still bothers you after a week, talk to your doctor.

Some signs need faster help. Call your doctor the same day if you feel confused, very sleepy or shaky, or your speech slurs. This matters most if your liver or kidneys are weak, or if you take large doses.

What does L-Glutamine help with?

L-Glutamine is an amino acid. Your body makes it, and you also get it from food such as meat, eggs and dairy. It is sold as a powder or capsule, often for gut health or for sport.

IBS with loose, frequent stools
Good evidence — clinical trials in people with diarrhoea-type IBS; sizes and doses not recorded in this file. In clinical trials, people with diarrhoea-type IBS took glutamine. They had fewer bowel movements, firmer stools and less gut discomfort. The trial sizes, doses and journals are not on file here.
Evidence grade B · Traditional tier T0
Getting back on your feet after major surgery
Early evidence — use in hospital clinical nutrition; no trial sizes on file. After major surgery, the body uses up its glutamine fast. That drop is well documented, and it can slow healing. Hospital feeding plans often add glutamine to support repair and cut infection risk, but no trial sizes are on file here.
Evidence grade C · Traditional tier T0
Sore muscles after hard training
Early evidence — early human exercise studies; no sizes or doses on file. Hard training lowers glutamine in blood and muscle. That much is well measured. In exercise studies, topping it back up may cut muscle breakdown and shorten soreness, though no trial sizes or doses are recorded here.
Evidence grade C · Traditional tier T0
The immune dip after long, hard endurance sessions
Evidence doesn't support this — studied in athletes, but no clear result on file. Hard endurance work is followed by a few hours of weaker immune defence. Some people call this the open window. Glutamine has been studied around training for this, and this file holds no clear result.
Evidence grade D · Traditional tier T0
Crohn's disease and ulcerative colitis, as an extra support
Evidence doesn't support this — hedged clinical reports only; no trial result on file. In these conditions the gut lining is damaged, and glutamine turnover runs high. Some clinicians add it to support lining repair. No trial result is on file, and it is not a swap for medical care.
Evidence grade D · Traditional tier T0
Keeping your defences up during stress or illness
Not yet tested in people — cell biology only; no human trial on file. It is well established that immune cells use glutamine as a main fuel. Blood levels fall during illness, heavy training and high stress. Whether taking it keeps those cells working better in people is not shown by any study on file.
Evidence grade insufficient · Traditional tier T0
Leaky gut and a loose gut wall
Not yet tested in people — established cell biology; no human study on file. Glutamine is well established as the main fuel for the cells lining your small intestine. That is general biology, not a trial of this supplement. This file holds no human study showing that taking it tightens the gut wall.
Evidence grade insufficient · Traditional tier T0
Sugar and carb cravings
Not yet tested in people — user reports only; no human trial on file. The brain can turn glutamine into glucose, which is basic biochemistry. Many people say their sugar cravings drop within 1 to 2 weeks, taking it with water between meals. Those are reports, not trial results.
Evidence grade insufficient · Traditional tier T0
Alcohol cravings in early recovery
Not yet tested in people — long use in recovery programs; no human trial on file. Recovery programs have used glutamine for years, mostly for alcohol. Users and practitioners report fewer cravings and steadier mood and energy in withdrawal. No human trial is on file, and it is used beside other care, not alone.
Evidence grade insufficient · Traditional tier T0

What L-Glutamine has not been shown to do

No study on file shows it seals or heals a leaky gut wall in people.
No trial here shows it helps IBS with constipation; the trials were in the diarrhoea type.
No human trial on file shows it stops drinking or treats alcohol addiction on its own.
No result on file shows it prevents colds or infections in healthy people.
No study here shows it builds muscle size or makes you stronger.
The craving reports are what people said, not a measured drop in sugar intake in a trial.

How to read this:

Grades run from A to D, plus insufficient. A means several good human trials agree. B means at least one good human trial. C means small or early human studies. D means the human evidence is weak or mixed. Insufficient means no human study is on file, only lab work, body chemistry or long use. This page sets out options and findings. It is not advice, and it is not a plan for treating illness.

What can L-Glutamine help prevent?

Gut lining breakdown during high physiological stress (surgery, critical illness, intense training)
Exercise-induced drops in immune cell activity in high-volume athletes
Chemotherapy-related oral mucositis (mouth sores): supported by clinical evidence

Which foods are rich in it?

L-Glutamine is found in high concentrations in protein-rich foods such as meat, fish, poultry, and dairy products. Other sources include legumes, nuts, and certain fruits and vegetables such as cabbage, spinach, and beets.

Interactions

These are some possible interactions. Please consult with your doctor.

Anticonvulsants (phenytoin, carbamazepine, valproate)

glutamate conversion may reduce seizure control.

Type: Documented interaction

Interaction level: Medium

Lactulose in hepatic encephalopathy

added ammonia load may oppose treatment.

Type: Documented interaction

Interaction level: Medium

Methotrexate

glutamine may alter tumour uptake and toxicity; oncology supervision needed.

Type: Documented interaction

Interaction level: Medium

Cisplatin and other chemotherapy

glutamine timing debated; coordinate with oncology team.

Type: Documented interaction

Interaction level: Medium

Growth hormone therapy

additive effects on gut and nitrogen balance, generally unstudied.

Type: Documented interaction

Interaction level: Medium

Reference

What are possible side effects?

L-Glutamine is generally well-tolerated, but some people may experience mild side effects such as:

Nausea
Diarrhea
Headaches
Stomach upset
Dizziness
Fatigue
Skin rashes

What's the recommended daily dose?

The recommended daily dose of L-Glutamine for adults is between 5-15 grams per day, depending on individual needs and health goals.

How many days does it take to work?

The time it takes for L-Glutamine to work varies depending on the individual and the condition being treated. Some people may experience benefits within a few days, while others may take several weeks to see improvement.

What time of day is best to take it?

There is no specific time of day that is best to take L-Glutamine. It can be taken at any time of day, depending on individual preference.

Is it best to take it with or without food?

L-Glutamine can be taken with or without food, although it is recommended to take it on an empty stomach to increase absorption

Track this remedy in the app

Track L-Glutamine with reminders and see your options for Gluten Sensitivity in the app.

Evidence grades and traditional-use labels are explained in our methodology. Nothing here is medical advice.

L-Glutamine

Home

Helps

L-Glutamine

Quick Facts

Track this remedy in the app

What is L-Glutamine?

How does it work?

What are the active ingredients that are important for its medicinal properties?

What forms does it come in?

What can happen if I have an imbalance or deficiency?

When was it first used for medicinal purposes?

If this is an emergency

Who should avoid L-Glutamine?

When should you see a doctor?

What does L-Glutamine help with?

What L-Glutamine has not been shown to do

How to read this:

What can L-Glutamine help prevent?

Which foods are rich in it?

Interactions

Anticonvulsants (phenytoin, carbamazepine, valproate)

Lactulose in hepatic encephalopathy

Methotrexate

Cisplatin and other chemotherapy

Growth hormone therapy

What are possible side effects?

What's the recommended daily dose?

How many days does it take to work?

What time of day is best to take it?

Is it best to take it with or without food?

Track this remedy in the app

Remedies related to L-Glutamine

People take L-Glutamine when they say

Conditions where L-Glutamine is recommended

Natural options for Gluten Sensitivity, ranked by evidence