Glutamine
Glutamine is the most abundant amino acid in human blood and skeletal muscle. It is conditionally essential, meaning your body usually makes enough, but demand can outstrip supply during heavy training, illness, or surgery.
Why It Matters
Glutamine is the preferred fuel of enterocytes (gut lining cells) and immune cells. Standalone glutamine supplements were heavily marketed for muscle growth in the 90s, but the research did not hold up; whole-body protein synthesis is not boosted by extra glutamine when total protein is already adequate.
Where glutamine may still help is gut health and recovery from extended endurance work or illness. For most lifters eating sufficient protein, the glutamine already in whey covers daily needs without adding a separate product.
How to Spot It on a Label
Glutamine often appears on whey amino panels at around 4 to 5 grams per 25g protein scoop. Standalone L-glutamine powders are sold by the bulk gram. Some labels list it as glutamic acid + amide, which is the same thing on the panel.
Examples from real products
Related Terms
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