What is L-glutamine good for?
Glutamine is an important amino acid that supports gut health, the digestive system, and also the immune system.
It is actually the single most abundant amino acid in the entire body, and although your body can produce most of the glutamine that it requires for its regular functions, when your body is subject to intense, stressful conditions, you will often require more glutamine than what you can produce.
How glutamine works
When the body is stressed from injuries, infections, trauma, burns, or surgery for example, or has performed high intensity exercise, it releases a hormone called cortisol into the bloodstream, and high levels of cortisol can reduce the amount of available glutamine in your body.
If your need for glutamine exceeds your capacity to create it, your body will start to break down protein stores, such as muscle, in order to obtain more of it.
This is where dietary and supplementary glutamine comes into play, and it is the reason why glutamine is often included in peoples pre-workout or post-workout supplementation.
Studies have found that glutamine significantly reduces muscle soreness and improves recovery times when compared to a placebo.
Role in the immune system & gut health
However, glutamine's most important function is more related to its role in the immune system, rather than in muscle recovery. Glutamine serves as a critical fuel source for immune system cells, such as white blood cells, and also works with certain intestinal immune cells.
Specifically, it helps protect the barrier between the inside of your intestines and the rest of your body, preventing harmful bacteria or toxins from moving past this barrier into the rest of your body. The intestines are, after all, the largest component of our immune system.
Not only have studies shown that taking glutamine supplements strengthens your immune system and reduces the risk of infections, but it has also been proven that the immune system can be compromised if glutamine isn't available in sufficient amounts.
This can lead to a vicious cycle when our body is suffering from an infection, as we are essentially fighting a battle against glutamine depletion on two fronts: The increased cortisol caused by the infection depletes the glutamine that the immune system needs in order to fight the infection.
When should I take L-glutamine?
L-glutamine is generally recommended to be taken between meals in order to enhance absorption. There are actually two forms of glutamine, one is known as "free form" L-glutamine, and the other is known as trans-alanyl-glutamine or alanyl-L-glutamine, with the latter said to be easier to absorb than free-form glutamine.
Regarding the best time of day for taking L-glutamine, there is conflicting data regarding how glutamine interacts with dopamine production and sleep quality. While I hunt down this information, I would recommend testing for yourself if you notice improved sleep quality after taking glutamine in the evening or just before bed.
Meanwhile, by default, let's say that glutamine is best taken during the day, to be on the safe side.
What does L-glutamine combine well with?
L-glutamine with collagen, for collagen synthesis
Research shows that glutamine supplementation can help stimulate collagen synthesis, which makes glutamine and collagen a perfect combination for getting the most out of your collagen supplements.
L-glutamine with creatine, for muscle recovery & growth
Also, it has been observed that when L-glutamine is combined with creatine, they work together to help reduce exercise fatigue, promote muscle recovery and enhance muscle growth.
What are natural sources of L-glutamine?
If you are interested in achieving your daily L-glutamine intake through your diet, rich sources of L-glutamine include:
- Chicken
- Turkey
- Beef
- Lamb
- Pork
- Eggs
- Seafood
- Milk
- Cheese
- Yoghurt
- Nuts
- Cabbage
L-Glutamine data sources & further reading
- https://draxe.com/nutrition/l-glutamine-benefits-side-effects-dosage/
- https://www.weightandwellness.com/resources/articles-and-videos/l-glutamine-deficiency-signs-supplement-benefits
- https://examine.com/faq/fact-check-does-glutamine-build-muscle/
- https://www.mountsinai.org/health-library/supplement/glutamine
- https://www.healthline.com/nutrition/glutamine
- https://www.lifeextension.com/wellness/supplements/glutamine
Last updated by Asklepios on 30th January, 2025