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Forget L-Glutamine Supplements for Muscle Growth

Brian Turner

Posted on June 01 2018

By: Robert A. Schinetsky


 The supplement industry is littered with all kinds of ingredients touted to deliver game-changing gains, superhuman performance, and Wolverine-like recovery. Truth be told though, there’s a relatively small number of ingredients that actually have been proven to work time and again in humans. Among these proven supplement commodities are creatine, beta alanine, betaine, and caffeine, and they’ve been used in supplements for quite a long time.

 There’s another OG supplement that’s still used in vast quantities these days, and it too was once considered a “must have” for building muscle and improving recovery. Today’s ingredient spotlight is on Glutamine, and it’s time to shed some light on this wannabe muscle building supplement.

What is Glutamine?

 Glutamine is a conditionally essential amino acid. In your body, you have essential amino acids, which are amino acids that your body CANNOT produce on its own and it must obtain through the diet, either from whole foods or amino acid supplements. Nonessential amino acids are one that the body can produce on its own from other amino acids, fats, and carbohydrates.

 Now, conditionally essential amino acids are ones that under normal circumstances, the body has ample supply of; however, in times of illness, injury, or extreme stress, the body can’t synthesize enough to keep up with demand, shifting the amino acid from conditionally essential to essential. Glutamine falls into the category of conditionally essential, as your body usually has more than enough glutamine stored for its needs. In fact, glutamine is the most abundant amino acid in the body, stored all over your body, but especially rich in your skeletal muscles (61% of your muscles consist of glutamine).

What does Glutamine do?

 Glutamine is involved in a number of processes in the body. As an amino acid, glutamine is involved in the construction of various proteins in the body, which is in part why many mistakenly assume it’s a “muscle building” supplement.

Glutamine is produced in your muscles and is sent out into the blood to the organs that require it. It serves as a type of “fuel” for many different cells (including lymphocytes and macrophages) in the body, due to its high nitrogen and carbon content. This becomes especially important following severe injury and/or surgery, as nitrogen is needed for wound repair and optimal organ function. In fact, about ⅓ of the nitrogen needed for these processes is derived from glutamine. It’s in these type of situations that demand for glutamine increases, and the body cannot produce sufficient glutamine.

 Glutamine is also involved in cognitive function as well, as it serves as the precursor for the excitatory neurotransmitters glutamate and aspartate as well as the inhibitory amino acid, gamma-aminobutyric acid (GABA).

Glutamine for Muscle Building?

 Given glutamine’s high concentration in muscle and its rich nitrogen content, it’s easy to see why many would think that supplementing with it could enhance muscle growth and recovery. Afterall, muscle growth and recovery boils down to maintaining a net positive nitrogen balance in your muscles where nitrogen input exceeds nitrogen output.

 So, in theory during periods of “injury” (i.e. skeletal muscle breakdown induced by exercise) nitrogen (from glutamine) is needed to support the repair efforts and fuel the immune cells that are repairing your damaged muscle cells. It’s easy to see why supplementing with glutamine can be beneficial.

 However, when you really start to look at the science of glutamine supplementation, the research tells a very different story. While early studies with glutamine noted that it was useful for burn victims, individuals with stomach ulcers, and muscle-wasting diseases (such as AIDS), those studies by an large administered glutamine intravenously, meaning it was injected directly into the bloodstream.

 However, in otherwise healthy individuals who are looking to use glutamine to enhance recovery and muscle growth, the research tells a very different story. Multiple studies have been conducted and found absolutely no benefit on recovery, muscle growth, athletic performance, or strength from glutamine supplementation.

Glutamine & Exercise Reserach

 A study involving healthy young adults performing resistance training supplemented with 0.9g/kg of bodyweight for six weeks. At the conclusion of the trial, researchers concluded:

 “We conclude that glutamine supplementation during resistance training has no significant effect on muscle performance, body composition or muscle protein degradation in young healthy adults.”

 Another trial assessed whether glutamine could be useful for accelerating muscle repair following eccentric exercise. Researchers found no evidence of a beneficial effect of oral glutamine supplementation on muscle repair following training or muscle soreness, two commonly cited reasons for using glutamine.

 A 2007 research review also concluded:

 “This review examines the effects of glutamine on exercise and demonstrates a lack of evidence for definitive positive ergogenic benefits as a result of glutamine supplementation.”

 And, another 2008 review on glutamine supplements in athletes stated:

 “the majority of studies have found no beneficial effects of maintaining plasma glutamine concentration, with glutamine supplements during exercise and recovery, on various immune responses after exercise.”

 Essentially what these studies are showing is that glutamine supplements do virtually nothing for increasing plasma glutamine concentrations, enhancing recovery, or building muscle.

 By now, you’re probably wondering why the early studies with glutamine demonstrated it was effective, but when used by the gym bros, it wasn’t.

Glutamine has terrible bioavailbility

 Early research studies with glutamine were in critically injured or ill individuals. They received their glutamine via injection or administered through an IV. That means the glutamine is directed put into your bloodstream. Studies with glutamine supplementation in athletes used oral supplementation, where glutamine was ingested via liquid, capsule, or powder, and it’s here we see the problem with glutamine.

 It has incredibly low bioavailability. In other words, when you consume glutamine orally, it’s not taken up very well by the body. This has to do with the fact that the stomach, liver, and intestines LOVE glutamine. They’re greedy, they don’t want to share glutamine. And, when you consume glutamine supplements, the glutamine passes through all of those organs before it has the opportunity to enter your bloodstream and be delivered to your muscles.

 Essentially, those expensive glutamine supplements are gobbled up by your GI system, and never really make it to your muscles.

 And, to further drive home the point, other research indicates that supplementing with glutamine may actually harm you.

Negative Effects of Glutamine

 A 2014 review analyzed effects of glutamine supplementation on ventilated patients. Researchers noted that supplementing with glutamine did not reduce muscle protein breakdown (catabolism) and even increased de novo glutamine production, indicating that supplementing with glutamine may accelerate muscle breakdown.

 Furthermore, that same study noted glutamine supplementation can potentially increase the inflammatory response, and lead to excessive inflammation and complications.

 Other research indicates that glutamine supplementation can actually reduce phosphorylation of mTOR, the exact opposite of what you want when trying to maximize muscle growth.

 As if that wasn’t bad enough, other research indicates that certain tumors can “reprogram” themselves to run on different fuel sources (glucose is their preferred fuel source). Science has identified glutamate (derived from glutamine) can satisfy the glutamine needs of glioblastoma, one of the most aggressive forms of brain cancer.

 Given all the negative research on glutamine supplements, it’s only natural to wonder -- why do supplement companies continue to sell it?

Quite simply, GREED!

 Glutamine is an incredibly cheap ingredient, and a big reason it’s used to “fill out” low quality pre workouts, amino acid supplements, and protein powders. On top of that, supplement companies are hedging their bets that the average consumer doesn’t really know all that much about supplements, and they’re making millions off of the uninformed consumer.

 Advanced Molecular Labs is here to help sort through all the nonsense and deliver the truth about supplements to you, which is why we use only ingredients backed by human research in our supplements.


 At the end of the day, you don’t need to supplement with Glutamine. It’s not an essential amino acid, and can readily be synthesized from other amino acids in the body or obtained from any number of foods you consume on a daily basis, as the BCAAs naturally found in protein serve as precursors of glutamine.


As such, you won’t find any glutamine in either AML Pre Workout or AML Post Workout. We’ve done the research and provide only those supplements proven to deliver real results all in the effort to push your performance, muscle growth, and recovery to the next level.



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