Glutamine
Marketing claim· human dataAlso known as: L-glutamine
Widely sold for muscle and immunity, with little support in healthy trainees.
What it is
Glutamine is the most abundant amino acid in the body, widely sold for muscle growth and immune support. The body makes it, and any protein-containing diet supplies more.
What the evidence shows
Muscle and strength. Marketing claim· human data In healthy people who eat enough protein, controlled studies do not support meaningful gains in muscle or strength.
Immunity and the gut. Preliminary· human data Its credible evidence is in specific clinical settings — serious illness, trauma or gut injury — not in healthy athletes. Extrapolating from those situations to everyday training is where the marketing overreaches.
Who it suits
Mainly patients in defined medical contexts under supervision. For a healthy lifter it is one of the clearest examples of a well-marketed, low-value supplement.
Practical notes
Because the body already produces glutamine and gets more from food, supplementing rarely changes anything for a well-fed trainee. Spend your budget on total protein and training instead.
Sources
Frequently asked questions
- Does glutamine build muscle?
- In healthy people who eat enough protein, controlled studies do not support meaningful gains in muscle or strength. The body makes glutamine and gets more from any protein-containing diet, so supplementing rarely changes anything.
- Does it help immunity or the gut?
- Its credible evidence is in specific clinical settings — serious illness, trauma or gut injury — not in healthy athletes. Extrapolating from those situations to everyday training is where the marketing overreaches.
- So who actually needs it?
- Mainly patients in defined medical contexts under supervision. For a healthy lifter, glutamine is one of the clearest examples of a well-marketed but low-value supplement.
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Written and reviewed by Mathew Beale — MSc Biotechnology, University of Reading.
Last reviewed: