L-GLUTAMINE - A COMMONLY ASKED QUESTION

“I've asked several other people about taking L-Glutamine and would like a second opinion about dosages. If you read the labels from several different manufacturers, they all suggest different dosages at different times. Can you give me any practical advice for a 40 year male who's been lifting weights for about 15 years with little success?”

Hear from the expert himself, Tom Venuto …

The amino acid glutamine is taken by thousands of bodybuilders and athletes for its reputed recovery and "anti-catabolic" effects. An "anti-catabolic" substance works by preventing muscle from being broken down (catabolized), although some studies have suggested that glutamine can also increase protein synthesis, among many other reputed benefits ranging from growth hormone release to improved immune system function. However, instead of your first question being "How much should I take?”, you may want to ask yourself whether you need to take this
product at all.

No one seems exactly sure of the ideal Glutamine dosage - I've heard everything from 1.5 grams per day to 30 grams per day. In the book, "An Evaluation of Popular Fitness-Enhancing Supplements," Authors Neal Spruce and Allen Titchenal, PhD., write, "Typical dosages, extrapolated from studies that suggest benefit and indicate safety, are 2 to 20 grams per day." That's a pretty wide range, but most studies with positive findings (as well as anecdotal reports), suggest the middle to upper end of this range and then some.

In Bill Phillips' Sports Supplement Review, 3rd edition, he listed glutamine as one of his "top ten tried and true supplements," which made the product quite popular (and it remains so to this day). Regarding dosages, Phillips (who owned a supplement company at the time) wrote, "Precisely how much glutamine is required for a bodybuilder (not critically ill hospital patients, who have been the focus of most glutamine research) to support optimal muscle metabolism, enhance cell volume, and support the immune system has yet to be determined. However, my guess is that in addition to a diet rich in high quality protein, bodybuilders could benefit from consuming at least an additional 10 grams of glutamine a day."

Despite Glutamine's "top ten" and "must use" status (as proclaimed by the supplement gurus, there is little evidence that glutamine will increase muscle growth or provide ergogenic benefits in healthy, well-fed athletes, bodybuilders or exercisers. Most of the original studies on Glutamine were performed on people who were ill or recuperating from surgery and the research on strength and endurance trained athletes is mixed.

In one clinical study, (Ann Surg, 1989 (209) 455-461), Hammarqvist, et al, used a dosage of .25 grams per kilogram of bodyweight, which is 21 grams per day for someone who weighs 165 lbs. This study showed increased nitrogen balance in surgical patients, but this data can't necessarily be extrapolated to healthy strength trained athletes, the subjects were patients recovering from gall bladder surgery.

Certain medical conditions such as burns and recovery from surgery put the body in an extremely catabolic state. The body marshals all its resources just to help heal the injured condition of the body and bring it back to normal. This is NOT the same metabolic state as a healthy person trying to build muscle. When recovering from surgery, nitrogen (protein) loss in the body can be literally
thousands of times greater than the nitrogen loss created from strength training or exercise stress.

Some studies have shown favorable results in healthy athletes. For example, in a study by Rosene, et al in Medicine and Science in Sports and Exercise (1999; 31(5) S123), wrestlers maintained positive nitrogen balance using .35 grams per kilogram of bodyweight per day. For a 165 pound person, that's 26 grams per day. The length of the study was only 14 days, however.
Other studies have shown no benefits at all. A study from 2002 examined Glutamine and performance in healthy weightlifters. It was published in the Journal of Strength and Conditioning Research (16 (1): 157-1600. Researchers studied the effects of a high dose of glutamine (30 grams). The results showed that weightlifting performance was not enhanced in resistance-trained men. The length of the study was only three weeks and it was a double blind placebo-controlled study. The subjects were advised not to change their food intake during the entire study.

This was the conclusion of the researchers:

"Glutamine does not have ergogenic properties when taken orally (0.3 g per kilogram) 1 hour before resistance exercise."

Several years ago, I decided to experiment with glutamine for an entire 12 week pre-contest period leading up to a bodybuilding competition, wondering if it might improve my recovery during a time that my body was under heavy training and dieting stress. I used about 20 grams per day. Compared to the other 27 times I've competed, I noticed no improvement in results the year I used Glutamine. In fact, I placed poorly (4th). A few years later, I returned to the same competition and won 1st place, using no supplements whatsoever (except a multi vitamin and an
essential fatty acid supplement rich in Omega 3's - the "good" type of fat).

I realize this is only anecdotal, but for what it's worth, I do like to try products which show any possible benefit, in order to get some "real world feedback" before coming to any personal
conclusions or making recommendations to others.

When I tell people I don't use Glutamine today, I often get some weird stares as if I had three heads or something. "But isn't glutamine a 'must-use' supplement - like creatine????" they argue. Not in my book. Maybe it does something for some people, but personally, I achieve the
results I want (and even win bodybuilding contests) without it. I get plenty of glutamine from all the high protein food I eat (lean meat for example, is about 15% glutamine and red meat is particularly high in glutamine).

Personally, I feel that the supplement companies are being a little too "clever" in their marketing campaigns because they often make it sound as if taking glutamine will surely help healthy lifters grow larger and stronger muscles or that you will lose muscle (using the "fear of loss" tactic) if you don't take it when dieting or pushing the overtraining envelope. But there's very little proof that glutamine works in these contexts.

That said, Glutamine is not too terribly expensive and is one of those supplements that might be worth experimenting with during periods when you are under heavy training and or dieting stress to see if it might improve your recovery. Maybe you will see some benefits. Maybe you won't. If you do choose to try it, a reasonable dosage would probably be in the range of 10-25 grams and this would depend a lot on your body weight and degree of training stress.

Don't change your diet or training or anything else - just take the glutamine and see what happens. Measure the results carefully. Notice your strength levels, body composition and how you are recovering from your workouts.

**Then draw a conclusion based on YOUR OWN research and experience**.

Think for yourself, otherwise the marketplace and popular opinion will do the thinking for you.
The advertised benefits sound fabulous: improve recovery, reduce muscle catabolism, increase protein synthesis, boost immune function, improve glycogen synthesis, release growth hormone and increase muscle cell volume. However, whether glutamine actually helps healthy, well fed bodybuilders, athletes or exercisers gain muscle or prevent muscle breakdown in the real world remains to be proven.

Train hard and expect success, all-ways!

Source:
Tom Venuto, NSCA-CPT, CSCS
Fat Loss Coach based in the States

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