Diet & Nutrition

L-Glutamine Supplement: 5 Quality Checks You Must Look For

Have you considered taking an L-Glutamine supplement and you want to make sure you take it correctly? Perhaps you've never heard of this supplement, and you want to know more. If so, this is for you. We're going to go over five comprehensive quality checks that you want to look for when it comes to L-Glutamine. These checks can ensure that you get the most out of your L-Glutamine supplement.


What is L-Glutamine
What is L-Glutamine Typically Used For?
5 Quality Checks You Must Look For in Your L-Glutamine Supplement

  1. L-Glutamine vs. Glutamine: L-Glutamine Should be the Active Ingredient
  2. Know Your L-Glutamine Source: A Fermented Plant Source Is Superior
  3. Powdered vs. Encapsulated L-Glutamine: Powdered is a Better Choice
  4. Isolated L-Glutamine vs. Mixed L-Glutamine: Depends on Usage
  5. Look for Accurate Instructions on How to Take L-Glutamine for Your Needs

Bottom Line

What is L-Glutamine

L-Glutamine is a conditionally essential amino acid. This means that your body usually makes enough of it on its own without needing an additional supplement. L-Glutamine works like other amino acids, and it helps form the building blocks for the protein in your system. (1)

This amino acid is the most abundant in your system, and is primarily made and stored in your muscles. It performs several important functions including fighting inflammation, boosting your immune system's function, repairing cell damage, improving your digestive health and directing the other amino acids in your body to perform their jobs. (2)

Despite being a conditionally essential amino acid, there are instances where your body's natural supply of it isn't able to keep up with the demand. People who suffer from prolonged stress, traumatic injuries or illnesses may find themselves short or deficient in L-Glutamine. When this happens, you'll want to take a supplement to balance your flagging levels. (3)

What is L-Glutamine Typically Used For?

Although L-Glutamine has a variety of uses, it's popular for Leaky Gut, sugar cravings, weight loss, and exercise performance. We've summarised the following below.

  • Exercise Performance- Taking an L-Glutamine supplement increases your muscle's hydration levels, and it also enhances your cell volume. These two things allow you to exercise longer and harder without feeling fatigued or tired as quickly. (5)
  • Weight Loss- You have bacteria in your gut called Firmicutes that cause you to crave calorie rich foods because they feed on carbohydrates. In overweight people, their levels of Firmicutes are much greater those with a healthy weight. L-Glutamine has been shown to reduce levels of firmicutes in the gut. It also promotes fat burning, helps to prevent your cells from holding onto excess fat, boosts human growth hormone levels and increases lean body tissue and reduces waist circumference in non dieting overweight people. (6)(7)(8)(9)
  • Sugar Cravings- L-Glutamine helps to decrease sugar cravings by temporarily increasing endogenous blood sugar levels (but no more than a glass of water does). It does this by converting the glucose in your blood and increasing the amount of glucagon-like peptide 1 (GLP-1). (10) Incredibly however, l-glutamine has also been shown to balance blood sugar levels over a long period of time by stabilising the H1ac biomarker.
  • Leaky Gut- Inflammation and cellular damage are hallmarks of Leaky Gut, and L-Glutamine has two main ways it helps to heal it. First, it has anti-inflammatory properties that reduce the intestinal wall's inflammation levels. Secondly, it starts to heal any small cracks or holes that allow the bacteria and toxins to slip through. (11)(12)

Five Quality Checks You Must Look For in Your L-Glutamine Supplement

Not all supplements are created equal, and you want to make sure that you get the correct supplement to help support your body. The choice can be overwhelming at first, and this is why we picked out the five quality checks that you should apply to your L-Glutamine supplement to ensure that it's the correct one for your needs.

1. L-Glutamine vs. Glutamine (L-Glutamine Should be the Active Ingredient)

Many people use Glutamine and L-Glutamine interchangeably, but they're not identical. There are a few very small differences between the two, mostly where the atomic structure is concerned. You may see supplements advertising "Glutamine" as the active ingredient, but you want to look for supplements that have "L-Glutamine" instead. (13)

This is down to your body's digestion. If you're already having issues, you don't want to take something that your body has trouble breaking down, as this could add to your problems.

L-Glutamine typically comes from plant products, and goes through a thorough and unique filtration process to make it very easy to digest. This may not be the case with Glutamine. (14)

The amino acids in your body link together by peptide bonds, creating two mirror images that can coexist together but are not identical. These mirror-image peptide bonds are D-Glutamine and L-Glutamine. D-Glutamine helps with things like bacteria fermentation and is resistant to natural antibiotics. It has no nutritional value. (15) While unusual, some products labelled as glutamine may only contain d-glutamine which does not stimulate metabolism and has little to no benefit.

Double check that whatever supplement you choose to buy has L-Glutamine listed on the packaging as the active ingredient. For example look for something which says '100% Plant Based L-Glutamine'. It'll break down and absorb into your body quicker, and this can help you obtain the benefits faster.

2. Know Your L-Glutamine Source: Fermented Plant Source is Superior

Did you know that your L-Glutamine supplements can come from a variety of sources? This can make it confusing for someone who is trying to compare different L-Glutamine supplements. L-Glutamine traditional comes from:

  • Fermented Plant (Mainly Beets) Is Best- Your L-Glutamine should come from a fermented plant source. This type of L-Glutamine goes through a more drawn out filtration process that makes it ultra fine and bioavailable. This process involves fermenting plant products (breaking them down) with bacteria in a controlled setting, helping the L-Glutamine remain in a purer, rawer form. (16) Beets are the most common plant source used for l-glutamine.
  • GMO Corn- A lot of L-Glutamine products come sourced from GMO corn. This can cause problems because most grain products contain or are contaminated with gluten. Gluten can cause inflammation in people who are allergic, or who have problems with gluten sensitivity. Corn is also technically a grain so can cause cross-reactivity for people who have issues with gluten. Additionally, GMOs have links to transferring toxins to your blood, an increased risk of developing Alzheimer's Disease, and have been shown to cause stomach inflammation + much more. (17)
  • Shellfish- Another popular source for L-Glutamine supplements is shellfish. Although it can be a slightly better source than GMO corn for your L-Glutamine, there is still a risk for allergies or inflammation. Additionally, it's not broken down as much as when you get your L-Glutamine supplement from a plant source. (18) There may also be higher risks of heavy metal contamination as opposed to a plant source.

Double check the source for your L-Glutamine supplement if you begin to notice issues like reactions, bloating, gas or abdominal discomfort. Sometimes people will report one L-glutamine will agree with them more than another is this typically comes down to source.

3. Powdered vs. Encapsulated L-Glutamine: Powdered is a Better Choice

One of the first things you'll notice is that L-Glutamine supplements come in one of two forms. You can either purchase pre-measured L-Glutamine capsules, or you can purchase L-Glutamine powder. Simply because it's more convenient, a lot of people make the mistake of grabbing the encapsulated form. (19)

If you take a look at most L-Glutamine pills, you'll find that there is usually around one gram of L-Glutamine per capsule. This means that if you need to take 15 to 20 grams of L-Glutamine each day for your Leaky Gut Syndrome, you're going to swallow 15 to 20 pills. This can be counter productive and lead to more problems for your gut. (20)

Additionally, capsules contain other substances which can cause problems for your gut. For example:

  • Cellulose/Hyper Cellulose- The outer layers of each capsule contain cellulose, and this can cause you problems if you're taking L-Glutamine for gut health. Our bodies don't have the capability to break cellulose down, and this can cause digestive upset, gas, and more problems. (21)(22)(23)
  • Magnesium Stearate- Magnesium Stearate is a substance found in capsules. Ingesting too much of this substance at one time can cause diarrhoea, irritation to your mucosal layer in your intestines and it can potentially interfere with how well your body absorbs the L-Glutamine. (24)(25)

The L-Glutamine powder doesn't contain any of these ingredients because it doesn't have to stay contained when you ingest it. Instead, you can dissolve it in water or in a shake and take it that way without any problems. You are also able to pick the dose for your condition.

4. Isolated L-Glutamine vs. Mixed L-Glutamine: Isolated Is Better But May Depend on Usage

Often you will find that the l-glutamine found in supplements is mixed with other ingredients. For instance, to improve taste it may be mixed with additives, thickeners, artificial flavours plus other nasties. L-Glutamine may also be used as apart of different formulas which affects how it is absorbed.

How you ultimately decide to take l-glutamine depends on what you intend to use it for, because certain conditions require different requirements.

For instance, if you are taking L-Glutamine for Leaky Gut Syndrome, IBS, or weightloss, l-glutamine should be the only ingredient in the product. This will ensure that it does not compete with amino acids and other ingredients for absorption. (26)(27)

However, if you choose to take l-glutamine for muscle growth or exercise performance, l-glutamine can be taken with other amino acids and this may enhance its effectiveness for overall muscle growth and performance. (29)(30)(31)

5. Look for Accurate Instructions on How to Take L-Glutamine for Your Needs

One of the first things you'll notice when you start looking at L-Glutamine supplement labels is that the dosage instructions are very vague. They may also not be relevant to why you want to take the product.

  • For Leaky Gut, You should take your L-Glutamine for leaky gut on an empty stomach or between mealtimes with water. You shouldn't mix it with other supplements, food or smoothies, and you shouldn't eat right after you take it. Leaky Gut can require between 5 and 20 grams of L-Glutamine per day to help heal the small cracks or fissures in your intestinal walls. One study showed that you should take at least 0.5g of L-Glutamine per kg of body weight. For example, someone who weighs 60kg would take 60kg x 0.5g to get 30g of L-Glutamine per day. (32)(33)
  • For Weight Loss- You should take L-Glutamine for weight loss following the same structure as you would for leaky gut. L-Glutamine has been found to be an effective weight loss tool because it helps to curb food cravings, reduce calories hungry firmicutes and prevents appetite stimulation. Studies show that people tend to use between 70 to 100mg of L-Glutamine per kg of body weight for effective weight loss. This works out to roughly 4.7 to 6.8g from a 70kg individual, 6.3 to 9.1g for a 90kg individual and 7.9 to 11.1g for a 110kg individual. (34)
  • For Sugar Cravings- A serving size of 3 grams will usually stop the cravings. You can take it when you feel the cravings coming on. These sugar cravings should stop once you take L-Glutamine. Most sugar cravings will go away with a three gram dosage. (35) (36)
  • For Exercise Performance- There are no hard and fast rules for taking L-Glutamine with for muscle growth. It can be taken by itself or with other amino acids or foods. When you exercise, you burn L-Glutamine because you're working your muscles. To increase your exercise performance, you want to take between 5 to 20g of L-Glutamine per day to offset the amount you burn. (37)(38)(39)

L-Glutamine Supplement

Bottom Line

You want to get the most out of your L-Glutamine supplement, and following our five quality checks can help ensure that you take it properly. Additionally, it'll also help ensure that you're taking the correct form of L-Glutamine for your situation. Always talk to your doctor before you add something to your diet because they'll be able to tell if it's a good idea or if you should consider another option.

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