If you work out, odds are you've heard about glutamine supplements more times than you can shake a stick at. You've been told glutamine works and is safe, and you've even wondered if supplements help recovery after exercise. I noticed they even charge you extra for a scoop of this stuff at your health club juice bar! If you have heard me teach about supplements, you know passionate and animated I get when it comes to this amino because I know what you are not being told. There are facts about glutamine they don't want you to know. This is what I call the “dirty little secret.” Keep reading and you too will soon know this secret. Then I want you to wonder why all the other so-called “experts” keep hyping this stuff up.
What Is Glutamine?
Glutamine is an amino acid. It's actually the most plentiful amino acid in the human body. Proteins are made of amino acids. Amino acids in turn can be divided into:
1. Essential amino acids
We cannot make and must get from the diet. It is essential that we consume them.
2. Non-essential amino acids
We can make these. Its not essential that we consume these because we can make them.
Glutamine is a non-essential amino acid. We make this amino every day. If you were stranded on a desert island, this would be the last thing on your mind needed to help you survive.
Conditionally Essential Amino Acids
In the world of sports nutrition, glutamine is also called a Conditionally Essential amino acid. By conditionally, we mean that, under some conditions, our ability to make this amino acid may not be enough to suit our needs. When this happens, it temporarily becomes an essential amino acid. Another phrase that means the same thing is “semi-essential.”
It's this part about glutamine being conditionally essential that has people buzzing about this amino acid. The claims for these types of supplements are numerous but the most prevalent claim is that glutamine helps you recover faster from exercise and improve your exercise performance.
Conditionally Essential Amino Acids
According to the NSCA's Guide To Exercise and Sport Nutrition, these are the conditionally essential amino acids
| Glutamine | Arginine | Cysteine |
| Histidine | Prolline | Taurine |
| Tyrosine |
Remember, these are the amino acids that are usually not essential. It's only under certain circumstances (conditions) that our ability to make them is not enough to suit our needs. That is, they temporarily become essential when supplementation may be needed.
Glutamine Research
So when does it become conditionally essential? In other words, when might taking this as a supplement make sense?
The interest in glutamine helping people recover faster is based on clinical research. But fitness websites or magazines never tell us who the research is conducted on.
The majority of glutamine research involves sick people who have severe burns or serious illnesses like cancer or HIV. These are severe stresses on the body. In these cases, some research finds glutamine might help.
When this amino acid is given to sick people, their immune systems improve, they sometimes gain weight and recover faster after surgery. Because glutamine appears to work on these individuals, those in the supplement business started to market it to people who exercise – because exercise is stress too.
Another thing the ads don't say is sometimes the glutamine is injected although taking it orally probably will raise levels in the blood too. Taking it through an IV though will raise blood levels even more.
So, what about exercise? Does glutamine help exercise? There is some research noting glutamine might help immune systems function better. This might reduce over-training syndrome.
Many people who use glutamine supplements are bodybuilders or those who want to get stronger or recover from exercise faster.
Does glutamine help them?
Glutamine Exercise Research
Let's look at the human research on glutamine supplementation as it relates to exercise. If we know what the exercise research says, we can get a better idea of whether glutamine is right for us. Where possible I'll pick only research that involves healthy people and research that only used glutamine. I'll also try to show you how much glutamine was used also.
A 2015 study titled The Influence of Oral L-Glutamine Supplementation on Muscle Strength Recovery and Soreness Following Unilateral Knee Extension Eccentric Exercise, noted that glutamine (0.3 g/kilogram of body weight per day) reduced muscle soreness (DOMS) after eccentric exercise (8 sets of “negatives”) as well as improved recovery of peak torque during leg extensions compared to placebo. The study involved 16 healthy college-age individuals. The effects of glutamine appeared to be greater in men than women.
There are 2.2 pounds in a kilogram. So, if you want to know how much this is for you, divide your body weight in pounds by 2.2 and multiply this amount by 0.3. For example, a 180 pound person (180/2.2=81.8 kg), it would be 81.8 X 0.3 = 24.5 grams of glutamine.
In a 2015 study titled Is Long Term Creatine and Glutamine Supplementation Effective in Enhancing Physical Performance of Military Police Officers? researchers found no exercise improvement of either creatine or glutamine (0.03 grams/kilogram of body weight) in 32 military police officers.
A 2015 study titled Glutamine supplementation and immune function during heavy load training noted that 10 grams of glutamine improved immune function compared to a placebo in 24 athletes who were subjected to heavy load training for 6 weeks. While I can't tell what “heavy load training” refers to, I believe it's strength training with heavy resistance (loads).
In a 2015 study titled Effects of l-Alanyl-l-Glutamine Ingestion on One-Hour Run Performance, 12 endurance-trained men were given both 300 mg and 1000 mg of glutamine, mixed in a sports drink. Both of these drinks improved running time to exhaustion more than when the men received no hydration.
The amino acid was shown to improve time to exhaustion by 12.7% compared to when the men received only the sports drink. But, this difference was not statistically significant.
I do feel a 12.7% improvement would be “significant” to most runners, although from a statistics point of view, it was not deemed much better than just taking the placebo. This study was derived from a 2014 PhD dissertation.
In a 2015 review of research titled Glutamine as an aid in the recovery of muscle strength: Systematic review of literature, noted more research was needed in that they only found 6 appropriate/good investigations. In other words, they left out the flawed studies. What studies they found noted no significant differences -from the placebo group – in terms of recovery of strength following exercise.
In a 2003 study titled Effects of effervescent creatine, ribose, and glutamine supplementation on muscular strength, muscular endurance, and body composition, researchers noted that an 8-week strength training program combined a supplement containing glutamine, creatine, and ribose did not improve muscle strength, muscle endurance or body composition more than those who received a placebo. In this study, the supplement used contained 0.3 grams of glutamine, 5 grams of creatine and 2 grams of ribose.
One study from the 1990s titled Increased plasma bicarbonate and growth hormone after an oral glutamine load, found that 2 grams increased HGH levels in 8 of 9 healthy volunteers. I'm not aware of any other studies looking at glutamine and HGH levels.
See the SeroVital review for more insights.
Looking at the research, it appears things are not as rosy as some supplement companies would have people believe. If glutamine is going to work, I feel its effects would be most beneficial to highly trained aerobic and strength athletes as opposed to the “regular person” who goes to the gym a couple of times a week for an hour. In those people, I don't think this amino acid needs to be supplemented.
How Much Glutamine Works?
If the above studies are to be taken as “gospel,” then an amount based on body weight might be most appropriate. More than one study above used 0.3 grams per kilogram of body weight or 0.03 grams per kilogram of body weight. How much is that? Remember there are 2.2 pounds in a kilogram. So, if you were 180 pounds (82 kg), the amount would be between 2.4 grams and 24 grams.
On page 140 of the book The Athletes Guide To Sports Supplements, the authors state that 1.5-4.5 grams split into even doses before, during and after workouts are sufficient for improving the immune system and recovery following intense workouts. Unfortunately, no reference to show where this range came from is provided.
The National Strength and Conditioning Association (NSCA), in their book, the NSCAs Guide To Sport and Exercise Nutrition state “glutamine shows promise though the proper dosage remains unclear.”
Until better studies are done, I honestly don't feel anyone can say how much would be best or even if most people would notice an effect.
What's The Best Glutamine?
There really is no best brand. Research does not distinguish one brand from another as being better. For those brands that say they are “the best,” my advice is to ask the company to provide clinical evidence – involving humans – showing their brand of glutamine is better than others.
For those who want to try this as a supplement, it might be wise to look for a low-cost product from a company you have heard of. In the US, no government agency monitors supplements for quality. So, sticking to a more established company is wise.
Glutamine Side Effects
In healthy people, glutamine supplements are safe. Other than maybe some gastrointestinal issues if you take too much of it, I don't think most people will have an issue with it. Here are a few things to consider when taking this amino acid. This list is not complete:
- Stop taking glutamine at least 2 weeks before having surgery
- Start with less than is recommended for the first week
- Speak to your doctor if you are pregnant or nursing
- Talk to your therapist/pharmacist if you have bipolar disorder
- Speak to your pharmacist if you take any prescription medications
Does Glutamine Work?
This amino acid does have some research noting it might improve exercise performance in some people. But, there is not as much research as some believe. Several studies combine glutamine with other ingredients (creatine, HMB etc.) which also makes it difficult to know which contributed the effects.
So, what's the secret I mentioned in the title of this review? The “secret” is there is less research than most people think and not all of the research shows it works. If glutamine works, its effects might be best noticed in elite athletes (or very sick people) rather than the average person who works out a few times a week.
People are always looking for the next creatine – the next all-star exercise supplement. There are some really good supplements out there, and in its own context, glutamine might even, one day, be a contender for that title. Unfortunately, glutamine is going to have to go a few more rounds before I raise its hand in victory.