amino-acidEVIDENCEBUSOTC

L-Glutamine

aka Glutamine

Most abundant amino acid in blood and muscle. Substrate for glutamate synthesis (the main excitatory neurotransmitter). Used for gut health and athletic recovery.

Dose range5000–20000mg

Half-life—h

Onset—min

Safety5/5high evidence base

Mechanism of action

Substrate for glutamate synthesis, GABA synthesis, and glutathione synthesis. Primary fuel for enterocytes (gut lining cells). Crosses the blood-brain barrier and converts to glutamate within neurons. Conditionally essential under stress, illness, or intense training when demand exceeds endogenous synthesis.

History

L-glutamine was identified in the 1880s but its clinical importance emerged in the 1980s with the recognition that it becomes conditionally essential in catabolic states. Modern interest centres on gut health (Krzywkowski 2001 evidence for intestinal permeability) and athletic recovery. Unscheduled globally.

Benefits

Gut barrier function
EVIDENCEB
Multiple trials in IBD, IBS, and intestinal permeability.
Recovery from intense training
EVIDENCEB
Multiple RCTs.
Sugar craving reduction
EVIDENCEC
Anecdotal + small trials.

Side effects

Mild GI upset (high dose)raremild

Cited research

L-glutamine for intestinal permeability (Krzywkowski)2001
PMID 11583137 ↗
Glutamine for athletic recovery: meta-analysis (Cordova)2019
PMID 31132933 ↗
Glutamine pharmacology and clinical use review (Wernerman)2008
PMID 18761522 ↗

Where to buy

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Vendor	Product	Size	Price	Per unit
Double Wood Supplements 4.4	L-Glutamine — Double Wood	—	See vendor	—	Shop Ad
BulkSupplements 4.2	L-Glutamine — BulkSupplements	—	See vendor	—	Shop Ad
NOW Foods 4.1	L-Glutamine — NOW Foods	—	See vendor	—	Shop Ad
Amazon Marketplace 3.5	L-Glutamine — Amazon	—	See vendor	—	Shop Ad

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