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Some call it a bodybuilding staple.Others say it doesn't live up to thehype. Use our expert guide to see whatglutamine means for you! Tweet

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by Chris Lockwood, Ph.D.

Last updated: Mar 11, 2014

If your body was a country club for supplements, you'd see glutamine everywhere: chilling

by the pool, hobnobbing with directors, and playing entirely too much tennis.

As the most abundant amino acid in the body, glutamine can be found in muscle tissue,

plasma, and in nearly every animal product you ingest. On average, it constitutes a little

more than five percent of the amino acids found in animal-derived protein sources such

as meats, dairy products, and eggs. That may not sound like much, but make no doubt:

Glutamine is critically important to a wide range of bodily processes.

EXPERT GUIDES: GLUTAMINEWATCH THE VIDEO - 10:23

Something this important has to be an "essential" acid, right? Not exactly. Glutamine is

considered "conditionally essential." This means your body can produce enough to meet

its needs under normal circumstances, but not always. In other words, you need to

consume dietary sources of glutamine under certain circumstances when your body is

under extreme duress.

As a supplement, glutamine has plenty of die-hard fans. It also has detractors who say that

unless you are a recovering burn patient, this amino is best left on the shelf. I'm here to

sort through the research and help you decide if glutamine is right for you.

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"G LUTAMINE IS A NITR OG EN SPONG E.

IT MOPS UP AMMONIA AND SHUTTLES

NITR OG EN BETWEEN TISSUES."

WHAT IS GLUTAMINE?Glutamine is created in the human body when

the non-essential amino acid glutamate (or

glutamic acid) is broken down and binds with

nitrogen-containing ammonia molecules. Think

of glutamine as a kind of nitrogen sponge. It

mops up ammonia and shuttles nitrogen

between tissues, where it can be used for cell

growth and tissue repair, among many other

functions. It's been reported that some 30-35

percent of all nitrogen derived from protein

breakdown is transported in the form of

glutamine. Glutamine can also be broken down

to re-synthesize glutamate, which makes

glutamine a critical source of ammonia and

nitrogen.

Approximately 70 percent of your body's

internal glutamine is produced in skeletal

muscle, from where it travels to the small

intestine, kidneys, and white blood cells. These

are the dominant sites of glutamine usage.

Internal levels of this amino acid depend on various factors. Pregnancy and lactation

significantly deplete the body's glutamine stores, as do exhaustive exercise, illness,

disease, starvation or fasting, rapid growth and development, and other conditions of

extreme physiological stress. These are some of the conditions where increasing your

glutamine intake or considering supplementation is appropriate.

WHAT DOES IT DO?Glutamine—like other alpha-amino acids—is involved in regulating protein synthesis and

breakdown. However, there's far more to it than that. Glutamine significantly affects BCAA

metabolism, gut barrier maintenance, normal immune function, glucose formation, water

transport, neurotransmission, and more.

Your kidneys are a primary consumer of glutamine use that's where the ammonia cleaved

from glutamine works to maintain your body's acid-base balance. Anywhere you find

ammonia, you'll find glutamine. As metabolic acidosis increases—as in response to intense

training or a high-protein diet—renal uptake of glutamine soars. In fact, one study found

that just four days of a high-protein, high-fat diet, was enough to cause a 25 percent drop

in glutamine levels in the plasma and muscle tissue.

If all of these competing uses begin to outpace your body's ability to produce glutamine,

then you may start to show signs of deficiency, including muscle wasting, depleted

energy, and increased susceptibility to infections.

WHAT ARE THE PERFORMANCE AND PHYSIQUE APPLICATIONS?Despite glutamine's various functions, little evidence suggests it will directly result in

increased muscle mass, reduced body fat, or gains in muscle strength or power in normal,

healthy people. However, given how stressful intense training is on the human body,

athletes may see certain benefits from supplementing with significant levels of glutamine,

or from stacking it with other supplements.

One study found that when athletes suffered from mild dehydration, supplemental

glutamine increased exercise performance and enhanced fluid and electrolyte uptake

when combined with a glucose and electrolyte beverage. Supplementation has also been

shown to raise levels of growth hormone in response to cycling to exhaustion.

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Extracellular concentrations of glutamine have also been shown to activate the signaling

pathway mTOR, which is known to be responsible for increasing muscle size. However,

here again, the benefits of glutamine supplementation required that other conditions be

met: in this case, mTOR signaling appeared to require the presence of BCAAs (leucine,

most importantly), as well as some threshold level of cellular hydration.

In another case, collegiate track and field athletes who consumed four grams of glutamine

per day for eight weeks, along with a loading and maintenance dose of creatine, saw

greater gains in lean body mass than those who used creatine alone. This may sound

significant, but it's hard to draw conclusions over a mere eight weeks at such a low

dosage. Whether higher doses or a longer study would have resulted in significant

differences is anyone's guess.

WHAT ARE THE DIFFERENCES BETWEEN TYPES OF GLUTAMINE?Other than your stack, the most important thing to consider when selecting a glutamine

product is the delivery system. If you're purchasing a powder, capsule or tablet, then free

form L-glutamine works best. However, because glutamine is unstable, avoid ready-to-

drink beverages or protein bars claiming to contain supplemental L-glutamine.

If you favor RTDs and bars, look for the peptide-bound forms of glutamine, such as L-

alanyl-L-glutamine, glycyl-L-glutamine hydrate, or an ingredient listed as "glutamine

peptide." Just remember that the glutamine concentration of one of these peptide forms is

typically approximately 65-70 percent. In other words, there's only about 6.5-7g of

glutamine per 10g of glutamine peptide. Dose accordingly.

Regardless of the form, up to 90 percent of ingested glutamine is eliminated during first

pass. A mere fraction of the glutamine you consume will make it beyond your liver. The

majority of the glutamine you consume being eliminated by the digestive enterocytes and

immune cells within your gut.

It's best to avoid products that contain n-acetyl-l-glutamine (not to be confused with N-

acetyl glucosamine) or alpha-ketoisocaproyl-glutamine (also known as aKIC-glutamine).

Both the acylated and aKIC forms may be stable, but the existing evidence suggests that

they're both poor delivery forms for glutamine.

WHAT SHOULD I USE IT WITH?Consider stacking glutamine with sodium and other electrolytes first and foremost.

Glutamine transport occurs via a sodium-dependent mechanism, and it has been shown to

significantly increase cell volume, electrolyte absorption, and hydration. This might be

helpful for both endurance and physique athletes, the latter because cell water volume is

one of the many aspects of muscle hypertrophy. Significant decreases in cell water

volume can also inhibit mTor signaling, which is crucial to building muscle.

Other candidates to stack with glutamine include:

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"G LUTAMINE MAY INCR EASE CELL

VOLUME, ELECTR OLYTE ABSOR PTION, AND

HYDR ATION. THIS MAY BE HELPUL F OR

ENDUR ANCE AND PHYIQUE ATHLETES."

Other candidates to stack with glutamine include:

BCAAs: There are two main reasons why combining BCAAs and glutamine may promote

greater gains in muscle mass and performance. First, ammonia concentrations, and

therefore glutamine, directly affects BCAA metabolism. And second, mTOR signaling from

extracellular glutamine first requires the uptake of BCAAs, primarily leucine. BCAAs plus

glutamine might promote performance and muscle gains.

Citrulline: Glutamine functions as a precursor for arginine and NO synthesis by

transporting citrulline between tissues. Using glutamine with citrulline might boost

citrulline's ability to stimulate the production of

nitric oxide, which might lead to better oxygen

delivery and nutrient transport to skeletal

muscle. More nutrients to the muscle might

translate to better recovery and growth. That

may sound somewhat indirect, but then again,

a messenger substance like glutamine has its

hand in a lot of processes.

Alpha-Ketoglutarate: Like glutamine, aKG

serves as a precursor to glutamate and has

been shown to dose-dependently spare

glutamine degradation and increase mTOR

signaling pathways, as well as glutathione.

This means that glutamine, taken with aKG,

might boost the potential for muscle growth

and the production of glutathione, a powerful

antioxidant.

Glucose or N-Acetylglucosamine: Glucose

deprivation reduces glutamine uptake and

negatively affects cell growth and survival. If

you're on a low-carb diet, it appears that the

glycoprotein N-acetylglucosamine (NAG),

which is available in supplement form, might

be able to restore glutamine uptake and

metabolism, potentially boosting recovery and

cell function.

HOW SHOULD I TAKE IT?It appears that the daily intake of supplemental glutamine needs to be high—at least 20-30

g per day, consumed frequently—in order to raise plasma glutamine concentrations.

To provide some perspective, consider that critically ill patients usually receive a constant

intravenous infusion of between 20-30 g of glutamine per day. However, the bioavailability

of infused glutamine they receive is 100 percent. It's no more than 30 percent from orally

consumed glutamine. Thus, I recommend up to 30 g of glutamine per day in divided

doses throughout the day, preferably with meals or snacks containing carbohydrates to

support glucose utilization.

On training days, I recommend you consume glutamine prior to or during exercise to

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On training days, I recommend you consume glutamine prior to or during exercise to

support hydration, electrolyte transport, and BCAA metabolism. You could take 10 g

before, during, and after your workout, or you could reduce those dosages to 5 g if you

also dose in the hours leading up to or following exercise. On non-training days, consume

at least 5 g of glutamine at frequent intervals, at least every 2-3 hours, to sustain an

increase in plasma glutamine concentrations.

There appears to be no need to cycle glutamine. In fact, there's more evidence to support

the need for chronic ingestion of glutamine during periods of extreme physiological

stress.

ARE THERE ANY SIDE EFFECTS?There's a considerable amount of data supporting the lack of adverse reactions to

glutamine doses as high as 30 g per day. A recent 13-week toxicity study concluded that

the "no-observed adverse effect level" (NOAEL) for L-glutamine occurred at the highest

daily dose provided to male and female rats.

In a human, this dose equates to roughly 0.308 g of glutamine per pound of body mass

per day. For a 170-pound adult, that's a little more than 52 g of glutamine per day. Again,

this dose was shown to result in an extremely high level of safety with no documented

adverse effects.

WHAT'S THE BOTTOM LINE?Yes, glutamine is a key player in a whole host of functions that dramatically impact your

ability to achieve your overall health and fitness goals. However, if you're depending

solely upon glutamine or aren't using enough, you may be disappointed.

Maximizing glutamine's effects on your body requires you to use your head first. If you're

not training hard, your body probably can supply you all you need. But if you're the type

who punishes your body regularly, taking it in the right way could help you keep

performing at an elite level.

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ABOUT THE AUTHOR

Chris Lockwood, Ph.D.Dr. Chris Lockwood earned his Ph.D. in Exercise

Physiology and his M.S. in Exercise & Sports Science.

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48 Comments

Rep Power: 0

Body Stats

ht: 5'11"wt: 199 lbsbf: 21.0%

Doughboy818

Bioavailability is no more than 30 percent from orally

consumed glutamine. Recommended amount is 30G. Does

that mean to take 100G of glutamine daily? O_o

Feb 27, 2013 6:09pm | report

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Rep Power: 0

philipphilipx

Feb 28, 2013 12:31pm | report

Rep Power: 0

Body Stats

ht: 5'7"wt: 170 lbsbf: 11.8%

Mikeyhouser

There is so many holes in glutamine, but I swear I

recover faster whenever I take it consistently

Feb 28, 2013 1:38pm | report

Rep Power: 0

DrChrisLockwood

No, I am not recommending you consume 100g to

derive 30g. I am recommending up to 20-30g of L-

glutamine be consumed, per day.

Feb 28, 2013 8:14pm | report

Rep Power: 0

KammingaJ

The safety blurb says you can basically that .308g

times your body weight and this will give you the

correct dosage. Ex. .308g which is roughly 30% so

.308 x 200lbs=61.6grams per day to get your fully

absorbed 100%....

Mar 13, 2013 8:48pm | report

Rep Power: 0

atokad

well I drink a shake in the morning, 2 scoops after i workout

and casein at night. The protein bottle says it has 5g of

glutamine per scoop so i think i'm good

Feb 27, 2013 6:37pm | report

Rep Power: 0

Body Stats

ht: 5'6"bf: 9.0%

AlexisBT

I have to rate this article as a 1.... You mostly point out that

studies have proven over and over again that glutamine

supplementation is mostly useless. Then you go on and

provide a mostly unclear bottom line, in which you don't

provide any real conclusion.

Article Rated: 1

Feb 27, 2013 6:49pm | report

Rep Power: 0

DrChrisLockwood

I'm sorry that you felt the article wasn't up to your

expectations. I do, however, feel that I provided a

sound background about glutamine, in an easy to

understand format. I presented both sides of the

argument, for and against. Since much of research

occurs in a bubble (so to speak), and I have over 19

years of experience within this industry upon which I

also draw upon when I posit a theory, I tend to take

some liberties based upon those experiences. In

other words, it would have been irresponsible of me to

strongly recommend glutamine, as the data doesn't

currently support such a strong recommendation.

Equally irresponsible, though, would be to discount

glutamine supplementation altogether, b/c doing so

first and foremost assumes that EVERY study within

EVERY subject population and under EVERY

physiological and environmental condition has been

tested. It's good for my academia friends whom I

support with research grants that that isn't the case, or

else they'd be out of jobs and research would cease.

The point I'm trying to make is that I intentionally try to

provide an unbiased, but realistic perspective when I

author these articles. If you're expecting something

other than that, then I can see where you're

disappointed. Hope that helps. - chris

Feb 28, 2013 8:22pm | report

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Rep Power: 0

Body Stats

ht: 5'8"wt: 165 lbsbf: 7.0%

elzachary

Excellent article Doc! There is to much derision on this

particular topic. Glad to see an open minded approach in your

presentation. 30 grams a day.....wow!

Feb 27, 2013 7:41pm | report

Rep Power: 0

DrChrisLockwood

Thank you! Am glad you liked the article.

Feb 28, 2013 8:22pm | report

Rep Power: 0

Body Stats

ht: 6'0"wt: 180 lbsbf: 15.0%

Basketball22

Honestly all I see here is an article that says there isn't alot of

science backing glutamine but there still MIGHT be some

benefits so please keep spending money buying glutamine. I

love bb.com but most science I've seen on glutamine is too

inconclusive and other educated lifters who's opinions I trust

say roughly the same thing.

Feb 27, 2013 9:50pm | report

Rep Power: 0

Body Stats

ht: 5'10"wt: 140.8 lbsbf: 17.9%

boxedindj

Long story short with the article; if you push yourself

to really hard in the gym, then this can help to repair

as quicker than your body would do it on it's own.

If you are an easy going person during work outs, and

don't leave sore and sweating like a pig needing to

recover, your own body can fix that.

Feb 28, 2013 3:08pm | report

Rep Power: 0

DrChrisLockwood

@Basketball22. FWIW, I could care less if someone

continues purchasing glutamine, and anyone who

knows me would tell you the same about my

character. In fact, if you go back and re-read how I

wrote my recommendation, you'll see that I only stated

that the daily dose needs to be very hight to

potentially raise plasma glutamine levels; that IF you're

going to take glutamine, then here's how I recommend

consuming it.... Thanks.

Feb 28, 2013 8:28pm | report

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ht: 5'10"wt: 215 lbsbf: 12.0%

scubasqueekers

30 grams! Thats crazy! Here is a study concerning the long

term side effects of taking 40 grams of glutamine per day!

http://www.ncbi.nlm.nih.gov/pubmed/22990615

Feb 27, 2013 10:49pm | report

Rep Power: 0

Body Stats

ht: 5'10"wt: 163.14 lbsbf: 12.0%

WissamShami

very informative ... I will save some money to buy some

Glutamine .. I think it will help me ..

Feb 28, 2013 1:47am | report

Rep Power: 0

Body Stats

ht: 5'7"wt: 182 lbsbf: 12.0%

Musclefriendly

Smart athletes know which supplements work and which

ones are bogus. Glutamine is one of many ********

supplements and totally useless for bodybuilders.

Nonetheless the most successful bodybuilders and fitness

athletes emphatically promote the use of this nonessential

amino acid (glutamine), claiming all sorts of unfounded

benefits because these athletes are talking puppets owned

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benefits because these athletes are talking puppets owned

by their glutamine-selling sponsors within the greedy fitness

industry so they will promote whatever ******** supplements

their sponsors tell them to!

Feb 28, 2013 11:43am | report

Rep Power: 0

Body Stats

ht: 5'10"wt: 140.8 lbsbf: 17.9%

boxedindj

Pretty much, and now they are taking use of

bodybuilders to try and do the same. Then again,

some people may need it due to working long hours

or highly physical work etc etc, but unless you literally

put your body through absolute hell, then there's no

need for it and your body can repair itself naturally.

Feb 28, 2013 3:15pm | report

Rep Power: 0

DrChrisLockwood

@Musclefriendly. Not certain if you're attempting to

belittle me b/c you perceive that I'm some 'greedy

fitness industry talking puppet', or that I'm just not that

smart. I hope that, in time, you'll find that perspective

is enlightning, and that a re-read of the above article

will show that I attempt to remain scientifically neutral;

anything else, with so few human oral use

interventions from which to draw upon, would be

irresponsible and equally ignorant. Thank you

Feb 28, 2013 8:35pm | report

Rep Power: 0

Body Stats

ht: 5'7"wt: 170 lbsbf: 11.8%

Mikeyhouser

The one thing I wish he would touch on more is glutamine

supplmentation during a cutting phase vs. a bulking/building

phase.

My question: How much glutamine does one really need who

is eating plenty of carbs protein, fat and calories all

together??? Is it still dependent on exercise?

Feb 28, 2013 1:37pm | report

Rep Power: 0

Body Stats

ht: 5'10"wt: 140.8 lbsbf: 17.9%

boxedindj

It has nothing to do with diet or exercise, and will not

effect your body goals whatsoever. It will not help you

gain nor lose, is what I mean. It's used to help with a

quick recovery after putting your body through

torturing hell.

Feb 28, 2013 3:12pm | report

Rep Power: 0

DrChrisLockwood

@Mikeyhouser: To directly answer your question:

Nodoby knows at this point. There simply hasn't been

enough clinical trials, under enough conditions and

with varying types of exercise interventions, to

provide you with a definitive answer. I do tend to

agree with @boxedindj, though; that is, whatever is

occuring needs to be eliciting an over-reaching

(precursor to overtraining) response to probably make

any kind of noticeable difference.

Feb 28, 2013 8:39pm | report

Rep Power: 0

Body Stats

ht: 5'10"wt: 140.8 lbsbf: 17.9%

boxedindj

Informative, but confusing. I think short and simple with

minimum science and statistic ******** would have proven to be

a better article. But that's my opinion.

Feb 28, 2013 3:10pm | report

Rep Power: 0

DrChrisLockwood

Thanks for the feedback. I think it comes across as

confusing b/c I neither strongly recommend or don't

recommend this product. That is, people like answers

in 'black' or 'white'; the world, however, more times

than not exists in the grey.

Feb 28, 2013 8:41pm | report

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Feb 28, 2013 8:41pm | report

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ht: 5'10"wt: 140.8 lbsbf: 17.9%

boxedindj

@DrChrisLockwood

I got taught in my First Aid course all about grey and

how much it sucks. We got taught to think in black and

white. Yes, there are some grey, noticeably, in the

world. Even with supplements, exercises (etc). But

people just don't like them. Though, I do.. gives time

to be creative and uncertain. :p

Again, entirely my opinion and I applaud your research

and what not. It was educational, nonetheless.

Feb 28, 2013 10:25pm | report

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ht: 6'0"wt: 250 lbsbf: 20.0%

sk1951

How about buy the stuff and use it...like I do. *s*

Mar 11, 2013 7:12pm | report