Glutamine: Benefits and Dosage
What is glutamine?
L-glutamine, along with creatine and protein concentrates, is one of the most popular supplements in sports nutrition. Here's what's worth knowing about it.
Glutamine is the most abundant amino acid in the human body, making up around 60% of the free amino acids inside and outside muscle cells. It plays a role in immune function and speeds up recovery after training, among other things — which already tells you its overall effect on the body, and on gym performance specifically, is significant.
Glutamine is a non-essential amino acid, meaning your body can make it on its own, from glutamic acid (which is abundant in food) and ammonia, which is toxic and needs to be cleared from the body. That means the process of making glutamine is itself doing you a favor, since it removes a genuinely dangerous byproduct along the way.
Every tissue in the body can both produce and use glutamine. Outside of muscle, a large amount is also produced in the kidneys.
What does glutamine do?
Glutamine serves several important functions in the body:
- Supports immune function — every immune cell in the body relies on glutamine as a fuel source. With adequate supplementation, you may notice you simply stop getting sick as often. Glutamine is also given to post-surgical patients to lower infection risk.
- Has a strong anti-catabolic effect — meaning it helps prevent the breakdown of muscle tissue. Its effect here is noticeably stronger than that of any other single amino acid. When the body runs low on glutamine, it starts manufacturing it from other amino acids — pulled straight from muscle tissue. Supplementing with glutamine can help prevent that muscle loss while dieting.
- Supports protein synthesis — giving it real anabolic potential (the ability to support muscle growth). It also boosts the body's ability to release growth hormone, which not only supports muscle growth but also helps reduce fat stores. Some studies found that 2 grams of L-glutamine raised growth hormone levels by as much as 400%.
- Supports mucosal lining function
- May reduce cravings for alcohol and sugar
- Supports healthy brain function in various psychological contexts — the brain converts glutamine into glutamic acid and raises GABA levels, both of which are essential for proper nervous system function.
The best natural sources are wheat (wheat protein), followed by casein (milk protein), whey, and soy. Interestingly, plant proteins tend to be a better glutamine source than animal proteins here — the exception that proves the rule.
Glutamine dosage
How should you dose it? The most common approach is 5–10 g right after training, in the morning before breakfast, and again before bed. For best results, pair it with 5 g of creatine and 3–5 g of BCAAs. Total recommended daily intake generally falls between 5 and 20 g.
Glutamine is a supplement genuinely worth trying — one of the more reliable additions to a serious training diet.