What it is
Glutamine is the amide of glutamic acid, and that amide is both the reason it is specified separately from glutamate and the reason it needs careful handling. Commercial production runs a selected bacterial strain on a sugar feedstock, after which the broth is clarified, the amino acid is concentrated and crystallised, and the crystals are washed, dried and milled to the required mesh. Pharmacopoeial-grade material is tested for assay, optical rotation and residual chloride.
Formulation considerations
Dry stability is excellent; wet stability is not. In a sealed powder the amino acid is unproblematic over a long shelf life, but once dissolved it begins converting to glutamic acid and ammonia, and heat accelerates this considerably. That rules out hot-fill beverages and long-hold wet pre-mixes, and it means stability studies on any aqueous format must look at assay rather than only at appearance. In dry blends glutamine is largely inert, compatible with proteins, carbohydrates, electrolytes and flavours, and its near-neutral taste lets it be dosed at several grams without dominating the profile. Bulk density is moderate, and the crystalline habit flows well enough for direct capsule filling.
Applications
Typical uses are post-workout and recovery powders, amino acid blends, standalone glutamine powders, capsules and tablets, protein powder fortification, and enteral or clinical nutrition bases. The material is also traded for cell culture media. Available in bulk quantities, with pricing on application.
Applications
- Recovery and post-workout powders
- Amino acid blends
- Capsules and tablets
- Clinical and enteral nutrition
- Protein powder fortification
- Cell culture media
Handling and storage
Hold in sealed original packaging below 25°C in a dry store with relative humidity under 60%, away from heat. Typical shelf life is 36 months unopened. L-Glutamine hydrolyses in aqueous solution to glutamic acid and ammonia, with the rate rising sharply at elevated temperature and at pH extremes, so it should not be held in solution for extended periods or exposed to hot-fill processing.
Common questions
Can L-glutamine be used in a ready-to-drink beverage?
It is not well suited to it. The amide group hydrolyses in water, releasing ammonia and generating glutamic acid, which affects both assay and flavour over shelf life. Dry powders, capsules and tablets are the standard formats, and liquid applications usually call for a more stable derivative such as a dipeptide.
How soluble is L-glutamine in water?
Solubility is around 35 to 40 g per litre at room temperature, which is adequate for typical single-serve powder doses but low enough that concentrated pre-mixes will not hold. Dissolution is faster in warm water.
Is L-glutamine suitable for a vegan-positioned product?
The material is produced by fermentation on a carbohydrate substrate with no animal-derived inputs. A non-animal-origin statement can be issued with the lot documentation.
What documentation is supplied with each lot?
Each lot carries a Certificate of Analysis reporting assay, specific rotation, loss on drying and heavy metals, along with the Technical Data Sheet and Safety Data Sheet.