L-Glutamine
Also known as: glutamine, free-form glutamine
The most abundant free amino acid in blood and muscle and a primary fuel for intestinal and immune cells. It is a long-standing recovery ingredient, although a meta-analysis found no meaningful effect on performance or body composition in athletes; its more consistent use today is in gut-support formulas. It is inexpensive, neutral-tasting, and easy to include at gram doses.
Research summary
Fuel and nitrogen donor for enterocytes and lymphocytes; supports glutathione synthesis and intestinal barrier function.
Dosage
Daily amounts, of compound.
| Lowest studied | Typical range | Highest studied | Upper limit |
|---|---|---|---|
| 5 g | 5–10 g | 30 g | — |
5–10 g/day, often split, is standard in recovery and gut products; clinical trials have used far more (up to roughly 0.9 g/kg/day) without notable tolerability problems. Free-form glutamine is unstable in water, so ready-to-drink products should use a peptide-bound form.
Source material: fermentation-derived
Format suitability
- Capsule
- Powder
- Tablet
- Softgel
- Gummy
- Liquid
Gram-scale dose; 5 g is roughly seven size-00 capsules, so powder is the practical format. Degrades in aqueous solution, so avoid liquids.
Formulation notes
Frequently combined with zinc carnosine, collagen, and probiotics in gut formulas and with BCAAs in recovery blends.
Sources
Related ingredients
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