Glutamine: The Pinnacle Of Supplements?

This article will delve into the research on glutamine and try to determine exactly what it does and why many bodybuilders rate its efficacy so highly.
Glutamine, a non-essential amino acid, has earned a reputation among bodybuilders as the pinnacle of the anabolic amino acids. Is this reputation justified?

This article will delve into the research on glutamine and try to determine exactly what it does and why many bodybuilders rate its efficacy so highly.

What Is Glutamine & What Does It Do?

Two-thirds of the free-form amino acids inside ones muscles are glutamine and most of the glutamine in ones bloodstream is made in the muscles and organs. Glutamine is digested and altered in the intestine and therefore cannot be acquired directly from meals. Instead it is probably best to supplement, but we will get to that later.

Precursors to glutamine synthesis include many of the amino acids, in particular the branched chain variety. This underscores the importance of taking amino acids directly and high quality, protein rich, foods from which these aminos are extricated. However, glutamine used directly, in its amino acid L form, has a unique role in the muscle building process. Back in the mid 80s researchers found that free intramuscular glutamine levels and muscle protein synthesis rate were related (1).

In other words, the higher the level of free glutamine inside ones muscle, the faster the muscle grows. Furthermore, muscle cell swelling can cause muscle anabolism acceleration, as a result of glutamine intake. The theory is that water, ions and amino acids enter the cell under conditions of high serum glutamine.

The subsequent state of cellular hydration is supposed to influence the cells growth rate. Volumized muscle cells not only appear larger and get a better pump but assist in protein synthesis. Indeed, without adequate levels of glutamine, it is impossible for protein synthesis to occur. It must be remembered however that one needs to have a surplus of free-glutamine for any of these things to occur. The point here is that one should keep their muscle glutamine as high as possible.

There are other benefits to a high glutamine status. As well as being used to build proteins, glutamine delivers nitrogen atoms to enzymes that build nitrogen-rich molecules, such as DNA bases and amino acids. A high glutamine status can actually create other amino acids and DNA bases. This is incredibly beneficial for continued muscle growth and immune status in general. Glutamine will be delivered to the muscle when nitrogen (by-product of protein metabolism) is needed in the cell. Bodybuilders need a constant supply of nitrogen to maintain a positive nitrogen balance and create an anabolic environment for continued muscle growth.

Nitrogen Balance!
[ Click here to learn more. ]
Nitrogen Balance!
Any bodybuilder with a rudimentary understanding of the sport would know the key to gaining muscle is protein consumption. But how do we know if we are getting enough protein?
David Robson

Glutamine also acts as a powerful ammonia scavenger. Ammonia is a highly toxic substance to muscle cells. Glutamine is able to remove ammonia from the bodies tissues due to its having two nitrogen atoms as opposed to the one that other amino acids have. Having two nitrogen atoms also enables glutamine to transfer nitrogen to the muscles; exactly what a bodybuilder wants.

Glutamine increases the body's ability to secrete Human Growth Hormone (HGH). HGH assists in metabolizing body fat and helps to support new muscle tissue growth. Finally, glutamine may also be metabolised to form glucose in the liver, thus promoting glycogen storage in the muscle (2). Another reason a high glutamine status is important.

During training or other times of metabolic stress, the demand for glutamine markedly increases (3). Essentially, glutamine can significantly improve protein retention and nitrogen balance when microtrauma occurs as a result of intense training. Interestingly, glutamine has been used for years in emergency rooms for patients when their bodies are placed into stressful, catabolic, states due to their involvement in high trauma events.

Under these conditions the body pulls glutamine from the muscles to deal with more pressing problems, such as heart and liver failure. To prevent muscle breakdown, patients are given high doses of glutamine. To some extent, this is what happens to bodybuilders who subject their muscles to the stresses of training. Hence the need for high levels of glutamine. Glutamine is also an essential treatment for AIDS and chronic fatigue syndrome.

    In Short, Glutamine:

    • Prevents muscle catabolism
    • Promotes muscle anabolism
    • Increases nitrogen retention
    • Enhances the immune system
    • Enhances glycogen stores
    • Increases HGH secretion
    • Assists in maintaining the bodies acid/alkaline balance
    • Enhances gastrointestinal health
    • Helps to heal wounds
    • Helps with fat loss by preserving lean tissue

Specific Implications Of Training On Glutamine Status

The use of glutamine in the muscle is enhanced through four major pathways. A four-pronged attack on the bodies glutamine reserves occurs through the synergistic effect of these pathways.

  1. The output of cortisol is rapidly increased as training intensity is increased exponentially. The intestines need for glutamine is thereby instantaneously increased and this causes an acceleration of glutamine removal from the blood. Cortisol also promotes degradation of glutamine in the liver, further decreasing blood glutamine levels.

  2. Training increases bodily carbohydrate uptake. This usually causes a decline in blood glucose and insulin levels. Gluconeogenesis then occurs and this causes the liver to attract amino acids, particularly glutamine. The liver then transforms glutamine into carbohydrates.

  3. Weight training produces lactic acid (LA) as a by product of anaerobic metabolism. This LA passes into the blood and acidifies it, hence the muscle burning sensation at the end of a set taken to exhaustion. Blood PH (PH is a determination of bodily acid levels: 1 being most acidic and 14 being most alkaline, or basic) then drops and the kidneys detect this. The kidneys are forced to attract glutamine rapidly to restore blood PH and consequently the acid/base balance.

  1. Training, as mentioned, activates the immune system. The immune system uses glutamine as a fuel, thus taxing it reserves further.

Sources Of Glutamine

Glutamine is found in many high protein foods such as dairy products, fish, beef and beans. Taking a protein supplement rich in glutamine in addition to carbohydrate, post exercise, may be sufficient to maintain glutamine status (4).

Better yet, take glutamine on its own. Studies have shown that if glutamine manufacture following training is sufficient, muscle glutamine can go about its job more efficiently (5). This translates to advancements in muscle protein synthesis.

A point worth remembering is that cooking tends to destroy much of the glutamine in foods. Raw spinach and parsley are better food sources.

Glutamine in supplement form is usually the best way of saturating the muscles with this crucial amino acid. It is best to take supplemental glutamine on an empty stomach. It is important to keep supplemental glutamine dry otherwise it will degrade into ammonia and pyro-glutamic acid.

A recommended dosage is five grams per day. However it would be best to experiment to find the ideal dosage as recommendations are based on the average person. There is no fear of toxicity with glutamine intake.


Glutamine: a non-essential amino acid that is essential for muscular growth. In light of the supporting research and its sheer popularity, glutamine, it seems, would be a worthy addition to any bodybuilders size gaining regime.


  1. NHLBI, National Institutes of Health, Bethesda, Maryland. (2001). The story of Glutamine Synthetase Regulation: Journal of Biological Chemistry: 276 44357-44364.
  2. Van Hall et al (2000) The Effect of Free Glutamine and Peptide Ingestion on the Rate of Muscle Glycogen Resynthesis in Man, International Journal of Sports Med 21, 25-30
  3. Groff J, Gropper S, Hunt S. Advanced Nutrition and Human Metabolism Second Edition. St. Paul, MN:West Publishing Company.1995.
  4. Lacey JM, Wilmore DW. Is glutamine a conditionally essential amino acid? Nutr Rev. 1990;48:297-309.
  5. Walsh, N.P. (1998). The effects of high-intensity intermittent exercise on the plasma concentrations of glutamine and organic acids. European Journal of Applied Physiology. 77:434.