What Is the Difference Between Glutamine and L-Glutamine?

Tyler Spraul is the director of UX and the head trainer for Exercise.com. He has his Bachelor of Science degree in pre-medicine and is an NSCA-certified strength and conditioning specialist. He is a former All-American soccer player and still coaches soccer today. In his free time, he enjoys reading, learning, and living the dad life. He has been featured in Shape, Healthline, HuffPost, Women's...

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UPDATED: Aug 25, 2020

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  • There is no real difference between glutamine and l-glutamine in supplementation.
  • The “L” in l-glutamine refers to the glutamine used by the left side of your body, which is the most effective for you.
  • Whether it says “l-glutamine” on the container or just “glutamine,” supplements always use l-glutamine.
If you are looking for glutamine supplementation to help you reach your fitness goals you may notice that some are labeled glutamine and others are labeled l-glutamine.

In theory, they are different. However, when it comes to glutamine supplements, they are the same whether or not there is an L in front of glutamine.

To reach your goals, it is important to pair supplements with a regular exercise routine. Go PRO today for access to certified personal trainers, workout plans, goal trackers, and more!

What Is Glutamine?

Glutamine is an important amino acid in the body and although supplementation of it is not necessary, many athletes and others concerned about their health will supplement their diet with additional sources of glutamine. See the video below for a quick overview of the supplement:

What Does the “L” in L-Glutamine Signify?

Many molecules exist in two different forms in the body. They are mirror images and not identical to each other, kind of like your right hand and your left hand. Most living things have these mirror-image molecules and glutamine is one of these, as are 18 of the other 19 amino acids in the body.

The “L” in l-glutamine stands for levo or left. For its mirror image, it is referred to as d-glutamine, with the “D” standing for dextro, or right. Although glutamine exists in a particular ratio of each right and left in your body, l-glutamine is the one that is of most use in your body.

Although not every supplement or ingredient is listed as l-glutamine, you can be assured that it is always 100% l-glutamine.

Who Should Take Glutamine?

Glutamine is a hugely popular supplement among bodybuilders and athletes who train intensely. The reason for this is because intense exercise can rapidly deplete the amount of glutamine in the muscles. This leads to exhaustion and can start to break the muscles down.

Athletes will often supplement with glutamine because it quickly replaces glutamine that has been depleted. This, in turn, helps to speed recovery after a workout as well as prevent you from losing muscle.

For those athletes who are also concerned with losing weight, glutamine can help, because along with preventing muscle loss it may also encourage fat loss.

Glutamine supplementation can also benefit you if you suffer from a weak immune system or fighting off an infection or illness.

Glutamine has been shown to improve the function of your immune system so it is good to take when you are going through a period of decreased health.

Glutamine can also be especially beneficial for those who have issues with their stomach or intestines, as well as for people with cancer.

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Are There Any Side Effects From Taking Glutamine?

Glutamine is a substance that is produced naturally by the body so there are very few side effects. If you take massive doses, you may notice certain side effects such as an upset stomach. Long-term effects of large doses of glutamine are not well known.

If you are breastfeeding or pregnant you should consult your healthcare professional before taking glutamine as not enough is known about the side effects during these times.

If you have a severe liver disease that is accompanied by confusion or difficulty thinking, do not take glutamine supplements as they could make these conditions worse.

If you are sensitive to MSG, or monosodium glutamate, you may notice a sensitivity to glutamine as well because once in the body, glutamine is converted to glutamate.

If you have certain mental disorders, such as mania, you should stay away from glutamine, as well. There is also the possibility that people with seizures will notice an increase in seizure activity with the use of glutamine.

Certain medications can also interact negatively with glutamine. Medications such as anticonvulsants, chemotherapy treatments, and lactulose may all have decreased effectiveness when taken with glutamine. Always check with your doctor if you are taking any medication, including herbal pills.

For more information about side effects and interactions, check out the WebMD info on glutamine.

How Much Glutamine Should I Supplement With?

Because glutamine is considered a dietary supplement, there is no set standard amount that is recommended to take on a daily basis. Depending on your health condition and activity level, your dosage may vary from four grams to 40 grams daily.

Talk with your physician to decide how much you should supplement with, if at all, and to monitor your results.

Frequently Asked Questions (FAQ)

Do I have to take supplements?

Unless your doctor has instructed you to take certain supplements, you do not have to take them.

Are supplements safe?

Whether or not dietary supplements are safe to take depends on a number of factors. Learn more about the safety of supplements here.

What supplements do I need to take?

No one can answer that aside from your doctor. To learn more about the various supplements that doctors commonly recommend, check out this article.

And don’t forget that supplementing is just part of an overall healthy lifestyle. Stay active and fit all year long with our PRO Plan. Check it out today!

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