Glutamine - The Who, What, Why, When & How

Posted in: Sports Nutrition  on Monday, August 18, 2008
The who, what, why, when and how of glutamine use as an ergogenic aid.

There are a lot of questions regarding Glutamine as a supplement for bodybuilders and fitness enthusiasts alike.  Both men and women seem to have an interest in knowing the who, what, why, when, and how of Glutamine use as an ergogenic aid.  Let’s start with the basics.

The proper name for Glutamine is L-Glutamine, and it is a conditionally essential amino acid.  Amino acids are the building blocks your body uses to synthesize protein, which makes up much of your body structures (muscle, skin, enzymes, hair, etc.).  At one time Glutamine was considered non-essential, not necessary to obtain in your food as your body is capable of making it from other amino acids.  The reason it is now considered conditionally essential is due to more recent research that determined the need or use of Glutamine within the body can often outpace the ability of the body to produce it.  Glutamine is actually the most abundant amino acid in the entire body.  What is more amazing is that Glutamine makes up more than 60% of the free amino acids within the muscles.  The term "free" generally means that this Glutamine within the muscle is not bound within protein structures and can be used within the muscle (for protein synthesis) or taken to other areas of the body where it is needed.  The muscles are actually the most adept at producing Glutamine compared to other tissues within the body.  As you will see, this might not be such a good thing for those trying to maintain their muscle mass.  It will be helpful if, for our discussion, you consider the muscles to be a Glutamine storage and production facility for the rest of the body.

One of the most important works that Glutamine is involved in is maintaining and synthesizing muscle protein.  In fact, it is this role that causes deficits in Glutamine to have a very negative effect on the skeletal muscles.  Whenever your body is under stress, from an illness, a burn, trauma, surgery, calorie deficit, excessive or intense prolonged exercise, or even mental stress, Glutamine will be released from the muscles.  Now you know why bodybuilders hate stress and always want to nap daily (believe me they are not just lazy, they want to get big).  Any time you remove Glutamine from the muscles you are not going to be helping yourself with muscle mass gains or your metabolism (less muscle = lower metabolism).  The reason your body takes Glutamine so easily from the muscles is that it is the most efficient at making the stuff.  The other tissues and cells of the body need the Glutamine to effectively perform their individualized duties such as your immune system cells or your intestinal tract.  Both of these systems and their cells use lots of Glutamine, especially during times stress to the body.  At this point you are in a depleted situation within the muscles and you end up chewing up muscle tissue to provide even more Glutamine.

If stress continues at high levels your body is forced to make more Glutamine by mobilizing Branched Chain Amino Acids (BCAA’S) (L-Leucine, L-Isoleucine, L-Valine) which are essential amino acids (you have to eat them in your diet because your body cannot make them).  In order to mobilize BCAA’s your body sends a chemical signal to start breaking down muscle proteins because that is where much of the BCAA’s are located.  Now we have real problems, not only are we not making muscle but we are starting to lose muscle to get to the BCAA’s which in turn are used to make Glutamine.  Part of what triggers the muscles to begin breaking down is when the Glutamine pool within the muscle is depleted the muscles begin to dehydrate.  When dehydration takes place protein synthesis stops and breakdown begins so the Glutamine pool can be replenished by making Glutamine out of the BCAA’s.  By the simple fact that Glutamine, if depleted, draws upon the BCAA’s for replenishment, and the BCAA’s are essential then you can easily see why Glutamine is considered to be conditionally essential.  The best thing that could happen when your body is under attack from some form of stress is to make sure that you provide it with lots of Glutamine and BCAA’s in the form of foods and/or supplements.

Let me share a little known fact about some of the products out there in the supplement marketplace today.  Have a look at some of the labels and you will see companies touting something called "Glutamine Peptide".  Sounds high tech right?  Actually Glutamine Peptide is an industry term that really has limited meaning.  Glutamine Peptide by definition is L-Glutamine, peptide bonded (a chemical bond between two amino acids) to another amino acid or several other amino acids in a chain (protein).  Within the supplement industry Glutamine Peptide means . . . . wheat protein.  What’s so great about wheat protein?  It is about 37% Glutamine compared to whey protein, which averages between 6% to 10% Glutamine.

There are two forms of Glutamine powder available, Glutamine Peptide and plain L-Glutamine.  Glutamine Peptide is usually found in meal supplement powders or added to other protein mixes because it is not a pleasant tasting ingredient.   However, the major benefit to Glutamine Peptide is that, because it is bound to other amino acids, it cannot be easily converted to Glutamic Acid (Glutamate) in the stomach.  The acidic environment of the stomach can cause some conversion of L-Glutamine powder to Glutamate, so that is why Glutamine Peptide has merit.   The other form, L-Glutamine powder, is not bad tasting, in fact it is slightly sweet.  As mentioned, the acid in the stomach affects it, or at least could convert it to Glutamate.  You want to consume the L-Glutamine powder on an empty stomach, usually with water so that it is not in your stomach for extended periods of digestion, and subsequent acid exposure, as would occur if consumed with a meal.  Capsules are generally filled with L-Glutamine and therefore you want to follow the same conditions as with the powder.  Take note, Glutamine Peptide in a capsule is absurd.  You would have to consume 10 capsules, assuming 1g per capsule, to get a 3g dose of Glutamine. You want to shoot for at least 10 grams per day, but more ideally you want to get 20 - 25 grams daily (5 grams five times per day).  You can mix the L-Glutamine powder in water or simply put a serving in your mouth and wash it down with water (don’t try this with the Glutamine Peptide, gag-o-rama).  No matter the method you will not be disappointed in the results.

As always, if you have questions, email me at  Until next month, "Train Smart, Eat Healthy, Supplement Wisely, Rest Well"