has been touted as an indispensible exercise
immune support supplement
since the early 90's and medical journals were raving about it years
before that. Now days, just about every bodybuilder on the planet
knows, uses and has seen the amazing results this amino acid champion
Although well established as an
exercise recovery supplement, many bodybuilders are unaware of its
truly profound benefit in assisting the immune system. Being the cold
and flu season, you might want to take particular note of its
well-documented immune system boosting and step up your use of this
particularly diverse and effective amino acid, ultimately important in
so many ways. Indeed, one of the more critical functions of
is its immune system support, as it is one of the primary precursor
compounds in the production of glutathione, the master antioxidant in
In a study to demonstrate its role in immune system function in
athletes, marathon runners reduced their incidence of respiratory
infection by one third when given oral glutamine immediately after the
race and then two hours later. Although the method of action from this
effect was not clear, it becomes apparent that
can be beneficial as a preventive supplement for athletes. 1
Other studies have indicated a strong immune boosting effect from
glutamine as well, even in the case of seriously ill patients
undergoing chemotherapy, bone marrow transplant and other serious
boosting along with exercise enhancement and recovery effects as well
makes glutamine one of the most indispensable athletic supplements next
. Although less revered than
creatine monohydrate (CM)
many experts feel that glutamine actually has more long-term potential
for promoting growth, strength and health than CM. CM works - no doubt
- but glutamine also works, and it does a lot more things than
creatine. To put it another way, if you look at creatine as if it's the
winner of the Olympic 100 meter dash - the fastest person in the world,
the absolute best at what it does - you could consider glutamine to be
the winner of the decathlon, the jack of all trades, the master of
many, and the world's best over all athlete.
Glutamine is an
one of the building blocks of protein. But it's much more than just a
building block for proteins. It has so many critical roles in so many
physiological processes - and especially those related to maintaining
and growing muscle mass - that even scientists consider it a legitimate
nutritional superstar. And athletes, from bodybuilders to marathon
runners, are increasingly accepting it as "standard issue", an
indispensable part of their supplement array.
Glutamine is the most abundant amino acid in the body. It's especially
concentrated in muscle where it makes up more than 60% of the "free"
amino acids, which are readily available for various uses by the muscle
or by other parts of the body.1
Although glutamine was once considered a non-essential amino acid,
meaning that the body did not need to take it in but could synthesize
it from others, it's recently been elevated to the status of a
conditionally essential amino acid, meaning that while the body can
indeed make glutamine, there are circumstances in which the need/use
outstrips the rate at which it can be made.1,2
This is true even though muscle can synthesize glutamine faster than it can any other amino acid. 3
Exactly why is glutamine so revered as a nutrient, especially for a
bodybuilder? One reason is because it serves as a direct regulator of
protein synthesis and breakdown in muscle. Muscle tissue is the major
site of synthesis and storage of glutamine.4
As doctors and scientists have been discovering over the past two
decades, any type of stress - trauma, surgery, burns, infections,
fasting, malnutrition, and hard or prolonged exercise - causes
glutamine to be released from muscle. 5,6,7,8
are proportional to the stress, and during the more extreme states of
stress/catabolism, glutamine stores can be very rapidly and
This occurs because glutamine is needed more critically by other
tissues of the body which cannot synthesize it, including cells of the
immune system and the intestines. Although this might sound strange,
the building of muscle tissue takes a back seat to functions which are
much more essential to actual survival, regardless of how mild or
extreme the situation might be. And, after all, the immune system does
play a critical role in the repair of tissue "damaged" by intense
Once depleted, glutamine is
virtually the last nutrient to be restored to pre-stress levels. What's
so important about this is that many experts feel that the amount of
glutamine in muscle is the single most important factor influencing the
rates of protein building and breakdown.10-12
When glutamine leaves muscle, not only is there no glutamine available
for incorporation to any muscle proteins that could've or would've been
branched-chain amino acids (BCAAs)
are also less available for protein synthesis because they are then used by the muscle to make up more glutamine (which may or may not be released from the muscle).
When glutamine leaves muscle, the muscle begins to dehydrate. And it's
now well known by bodybuilders, as well as scientists, that dehydration
leads to protein degradation. Conversely, as you might expect,
increasing the amount of water inside muscle fibers - which glutamine,
like creatine, does although not quite as dramatically - leads to an
increase in protein synthesis. 13
Studies with animals and many different groups of patients have
demonstrated that adding glutamine to their nutrient intake can reverse
protein catabolism and loss of muscle mass. Even though these studies
have not been conducted on healthy human athletes, the basic
physiological changes/responses to the situation are very similar to
those of hard training; and it's strongly suggestive that in these
studies glutamine prevented the loss of what are called myosin, heavy
chain proteins, because these are the ones that determine a muscles
contractile properties and capabilities.14
Over training in athletes - all too common in serious bodybuilders -
can lead to glutamine depletion and a weakened immune system, in
addition to impaired energy and performance. Experts have, in fact,
suggested that plasma glutamine concentrations - reduced from
severe/over training - can be used as a measure of both the relative
state of over training/overreaching and the recovery from this
Again, animal studies indicate that supplemental glutamine can mitigate
or neutralize the loss of muscle glutamine following exercise. 17
In addition to its anticatabolic and anabolic effects, glutamine also affects carbohydrate metabolism.18
A recent study in humans found that infusions of glutamine lead to
increases in blood glucose without any changes in either insulin or
glucagon, the two primary hormones that regulate glucose levels. 19
This could have a major impact when dieting down, cutting carbs, and
trying to minimize and stabilize insulin levels (to inhibit fat
deposition) and glucagon (to minimize cell dehydration and related
effects), especially since cutting carbohydrates and calories can
result in muscle protein catabolism. With glutamine converting to
glucose and fueling the brain and nervous system, precious muscle mass
In another study, glutamine
infusion, prior to exercise, resulted in an increased muscle glycogen
concentration two hours after exercise causing the researchers to
speculate that glutamine might serve as a direct precursor for muscle
glycogen replenishment after exercise.20
Glutamine has also been shown to affect the metabolism of free fatty
acids and fat deposition, all in ways that reinforce its potential
benefits for over weight individuals, as well as bodybuilders and other
Glutamine also appears to lower
the amount of exercise induced ammonia which can in turn increase
performance ability. High amounts of ammonia have been associated with
fatigue, nausea and mental confusion as well as lowering the ability of
muscle to contract. A study from 2007 involving football players showed
that this ammonia lowering ability of glutamine is "exercise intensity
dependent," giving further credence to its importance as an exercise
enhancement supplement. 21
Along with immune system support, exercise recovery and many other
benefits, studies have indicated glutamine can also have a beneficial
effect on the digestive tract showing a remarkable ability to support
the epethilial cell lining in the intestines to the degree that some
clinicians have suggested it as a serious remedy for gastro intestinal
disorders and diseases. For bodybuilders (even without any serious
digestive ailments) this equates to improved digestion of much needed
Another important function of glutamine was shown in a recent study
from May of 2008 which demonstrated that glutamine is an important
precursor to arginine, which further adds to its list of anabolic
With a good basic bodybuilding diet it should be almost impossible for
someone not to achieve significant and noticeable differences from just
20-25 grams a day.
To maximize recovery and growth, you have to keep glutamine stores in
muscle topped off. Every day. This is not a supplement that you need to
or should cycle. To reiterate: As long as glutamine content remains
high in the cell, cell hydration and anabolic processes remain
elevated. When glutamine leaves muscle, the cells lose water and
catabolic processes begin.27,28
It's not enough to take just a protein powder, not if you're really
serious, even if it's a really good one. Glutamine is not just another
amino acid building block of protein. You need glutamine just as much,
if not more, than you need creatine. In fact, the actions of glutamine
and creatine on cell hydration and increasing the energy stores of
muscle are mutually supportive and complement one another.
You can get glutamine from food as
it makes up roughly 4-8% of most food protein with the highest
concentrations occurring in milk, meat, and some nuts. You may get as
much as 10 grams a day from your diet, but that's very likely still not
optimal for serious training. And since the cells of the intestines are
such voracious consumers of glutamine, not much makes it through to
your muscles, except in very high protein diets. 29
To keep your muscles really flush, you probably need around 20-25 grams
a day in your diet and maybe more during the more extreme periods of
training and/or dieting. That means supplementing. And not just with
glutamine-enriched protein supplements. They may help, but they won't
usually give you that much unless you use very large amounts every day.
Taking glutamine will actually
enhance the biological value of the rest of the protein in your diet,
whether food or supplement. It does this by reducing the use of the
aminos in those proteins to make glutamine. They are therefore
available for use in synthetic - anabolic - processes in the muscles
The simple, easy way is to use a
supplement consisting of pure glutamine powder. Simply take a slightly
rounded teaspoon three or four or even five times a day: when you get
up, before bed, before and after your workout, and maybe one other
time. You can put it on your tongue and then take a drink. You can mix
it in a little water. It has very little taste, and certainly not an
The key is to include glutamine in
your supplement program and to take it consistently. Even 10 grams a
day will make a difference in your recovery. And better recovery is the
foundation for more overload, which is the foundation of bigger,
stronger muscles. And glutamine is not just for use when training hard,
it's made to order for whenever you're stressed, whether fighting off a
cold, flu, sore throat, dieting, sleep deprived, emotionally out of
whack, or more severely impacted by wasting diseases.
1. Lacey JM et al. Is glutamine a conditionally essential amino acid? Nutrition Reviews 1990; 48(8):297-309.
2. Smith RJ. Glutamine metabolism and its physiologic importance.
Journal of Parenteral and Enteral Nutrition 1990; 14(4
3. Golden MN et al. Glutamine
production rate and its contribution to urinary ammonia in normal man.
Clinical Science 1982; 62:299-305.
4. Newsholme EA et al. Properties
of glutamine release from muscle and its importance for the immune
system. Journal of Parenteral and Enteral Nutrition 1990; 14:635-675.
5. Newsholme EA et al. A role for
muscle in the immune system and its importance in surgery, trauma,
sepsis and burns. Nutrition 1988; 4:261-268
6. Wernerman J et al. The effect
of trauma and surgery on inter-organ fluxes of amino acids in man.
Clinical Science 1987; 73:129-133.
7. Rennie MJ. Muscle protein
turnover and the wasting due to injury and disease. British Medical
Bulletin 1985; 41(3):257-264.
8. Bulus N et al. Physiologic
importance of glutamine. Metabolism Clinical and Experimental 1989;
38(8 Supplement 1):1-5.
9. Furst P et al. Evidence for a
nutritional need for glutamine in catabolic patients. Kidney Int
Supplement 1989; 27:S287-S292.
10. MacLennan PA et al. Inhibition
of protein breakdown by glutamine in perfused rat skeletal muscle. FEBS
Letters 1988; 237:133-136.
11. Jepson MM et al. Relationship
between glutamine concentration and protein synthesis in rat skeletal
muscle. American Journal of Physiology 1988; 255:E166-E172.
12. Rennie MJ et al.
Characteristics of a glutamine carrier in skeletal muscle have
important consequences for nitrogen loss in injury, infection, and
chronic disease. Lancet 1986; 2:1008-1012.
13. Low SY et al. Responses of
glutamine transport in cultured rat skeletal muscle to osmotically
induced changes in cell volume. Journal of Physiology 1996; 492(part
14. Hickson RC et al. Glutamine
prevents the down-regulation of myosin heavy chain synthesis and muscle
atrophy from glucocorticoids. American Journal of Physiology 1995;
15. Keast D et al. Depression of
plasma glutamine concentration after exercise stress and its possible
influence on the immune system. Medical Journal of Australia 1995;
16. Rowbottom DG et al. The
emerging role of glutamine as an indicator of exercise stress and
overtraining. Sports Medicine 1996; 21(2):80-91.
17. Moriguchi S et al. Glutamine
supplementation prevents the decrease of mitogen response after a
treadmill exercise in rats. Journal of Nutrition Science Vitamins 1995;
18. Nurjhan N et al. Glutamine: a
major gluconeogenic precursor and vehicle for interorgan carbon
transport in man. Journal of Clinical Investigation 1995;
19. Perriello G et al. Regulation
of gluconeogenesis by glutamine in normal postabsorptive humans.
American Journal of Physiology 1997; 272(3 Part 1):E437-E445.
20. Varnier M et al. Stimulatory
effect of glutamine on glycogen accumulation in human skeletal muscle.
American Journal of Physiology 1995; 269(2 Part 1):E309-E315.
24. Welbourne TC. Increased plasma
bicarbonate and growth hormone after an oral glutamine load. American
Journal of Clinical Nutrition 1995; 61:1058-1061.
25. Bourguignon JP et al.
Endogenous glutamate involvement in pulsatile secretion of
gonadotropin-releasing hormone: evidence from effect of glutamine and
developmental changes. Endocrinology 1995; 136(3):911-916.
26. Haussinger D et al. Cell volume and hormone action. Trends in Pharmacological Science 1992; 13:371-373.
27. Hallbrucker C et al. Control of hepatic proteolysis by amino acids
? the role of cell volume. European Journal of Biochemistry 1991;
28. Remesy C et al. Inter-organ
relationship between glucose, lactate, and amino acids in rats fed on
high-carbohydrate or high-protein diets. Biochemical Journal 1978;
27. Carlson HE et al. Stimulation
of pituitary hormone secretion by neurotransmitter amino acids in
humans. Metabolism Clinical and Experimental 1989; 38(12):1179-1182.