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What is L-Glutamine and Where Does it Come From?
Glutamine or L-glutamine is what is known as a conditionally essential amino acid, which means that they can be synthesized within the human body except under certain conditions, for example illness or nutritional deficiency.
Approximately 90% of all glutamine in the body is produced in the muscle tissues, synthesized by the enzyme glutamine synthetase from glutamate and ammonia, with the remainder typically deriving from the lungs and brain.
Production of Glutamine
Regulated by the liver, glutamine is typically taken up in the gut by the cells of the intestinal wall.
Glutamine can also be taken up and utilized by the kidneys and macrophages, playing a somewhat relevant role in maintenance of pH balance in the body as well as general functioning of the immune system.
What Types of Glutamine are There?
Aside from L-glutamine that only major form of glutamine is isoglutamine which is derived from glutamic acid.
Isoglutamine doesn’t play any role as a dietary or sports supplement so we won’t be discussing it here.
What are the Benefits of Glutamine?
Glutamine can play a number of different roles within the body:
- Use as a fuel source similarly to glucose
- Transportation of ammonia throughout the body
- Maintenance of the positive nitrogen balance essential for muscle hypertrophy
- Stimulation of protein synthesis
While glutamine does play a role in protein synthesis and muscle hypertrophy in general it is important to note that its role is not nearly as vital as that of the essential amino acid L-leucine.
What’s more, it is not yet concluded whether the utilization of glutamine as a fuel source is actually worthwhile or if it is simply a wasteful consequence of overconsumption of this conditionally essential amino acid.
Who Can Benefit from Using Glutamine Supplements and How?
Bodybuilders and athletes are typically those of will tend to use glutamine supplements, and while it hasn’t been conclusively shown to provide any dramatic benefits it is still worth considering.
Anyone engaging in frequent high volume training with a lot of intensity could potentially benefit from using glutamine because of its apparently modest impact on muscle protein synthesis and immune function.
If you have ever felt rundown towards the end of a training cycle and are looking for something to perk you up a little then adding some glutamine to your existing supplements might be worth considering.
If you are working on a tight budget and are looking to really get the most bang for your supplement buck then you would probably be wise to opt for supplements that are more extensively backed by conclusive research because glutamine does not fall into this category.
Which Foods Contain Glutamine?
Examples of foods that contain glutamine include:
- Dairy products
Animal proteins will tend to contain higher concentrations of glutamine due to their very nature, and if you are consuming a large amount of protein then you may find that you are already consuming more than enough glutamine, thereby negating the need for glutamine supplementation.
Does Glutamine Have any Side Effects?
There are currently no known side effects associated with supplementation of glutamine in otherwise healthy adults; however, if you suffer from sensitivity to monosodium glutamate or MSG then you may experience side effects because glutamine is converted to glutamate within the body.
As with any dietary supplement, we recommend that women who are pregnant or breastfeeding consult their doctor or physician prior to use. This also applies to people under the age of 18 and individuals who suffer from pre-existing medical conditions or who are taking any kind of prescription medication.
Note: We recommend speaking to a doctor before taking any supplements.
How and When Should I Use Glutamine?
We recommend that you refer to the manufacturer’s guidelines.
Having said this, using glutamine first thing in the morning with breakfast and as part of your post-workout protocol seems to make the most sense anecdotally.
How Much Glutamine Should I Use?
Doses as high as 15g of per day have been shown to provide no side effects in healthy adults, but we recommend that you refer to the manufacturer’s guidelines on any product you purchase.
The exact amount you use will typically depend on your bodyweight and / or lean body mass (LBM) because this will dictate how much muscle tissue capable of taking up and utilizing glutamine you actually possess.
Is Glutamine Worth Using if the Science is Inconclusive?
None of the purported benefits of glutamine supplementation in healthy adults are backed up by conclusive peer-reviewed studies, so at this point in time it is important to bear this in mind when trying to look beyond the marketing claims of supplement manufacturers.
Context is the most important thing here, so if you are already using a wide range of supplements and can say with a great deal of certainty that they are all providing you with the benefits you seek then there is nothing wrong with running your own experiment and seeing if glutamine works well for you.
Whether or not you do this will depend on your budget, but please don’t think that glutamine is a magical supplement that will somehow fly in the face of the huge body of research that shows it to be ineffective compared to a placebo.
Author’s Note: Speaking somewhat anecdotally from experience, the main benefit of glutamine supplementation in bodybuilders seems to be that of immune support, especially during the winter months when the flu and common cold are running rampant.
Choosing the Right Glutamine Supplement
Choosing a glutamine supplement is not very difficult because it is typically only available in the form of L-glutamine, meaning there are no complicated choices to be made.
With this in mind it seems as if the main distinguishing factor is going to be the quality and reputation of the brand you are purchasing. There is more on this below so be sure to keep reading if you’re looking to get a clearer idea of which brands are more favorable over others.
1. Transparent Labs CoreSeries BCAA Glutamine
2. Optimum Nutrition Glutamine Capsules
3. BSN Glutamine DNA
4. MusclePharm Glutamine
5. Universal Nutrition Glutamine
6. Evlution Nutrition Glutamine 5000
7. Dymatize Micronized Glutamine
8. Betancourt Nutrition Glutamine Plus
9. BPI Sports Best Glutamine
10. AllMax Nutrition Micronized Glutamine