L-Glutamine
Abundant amino acid fueling gut lining cells and mucus; she takes it to protect the gut barrier.
Summary
Glutamine is the most abundant amino acid in circulation, fuels intestinal epithelial cells, supports the mucosal barrier, and is a glutathione precursor. Higher glutamine intake is associated with lower all-cause and cardiovascular mortality, and human trials show benefits in post-infectious IBS, pancreatitis, athletes' respiratory infections, and gut microbiome composition. She connects it to her 'autodigestion' concern (a thinning mucus barrier letting digestive enzymes leak) and to microplastics, which damage the barrier. A mouse Alzheimer's study also points to gut-microbiome glutamine metabolism as a pathway.
In her Jan 2026 stack because she is 'convinced that gut barrier function is essential for healthy aging'; noticed nothing in her first two weeks at 5 g/day.From My Current Supplement Stack for Longevity
The evidence
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Human trial
In patients after an enteric infection, randomized to L-glutamine or placebo for 8 weeks, glutamine gave a 14-fold decrease in post-infectious IBS-D and reduced intestinal permeability.
Read the study Discussed in L-Glutamine for Gut Barrier Function -
Human trial
A meta-analysis of glutamine supplementation studies in pancreatitis found about a 70% reduction in mortality.
Read the study Discussed in L-Glutamine for Gut Barrier Function -
Human trial
In a clinical trial, 14 days of L-glutamine (30 g/day) shifted the gut microbiome from an obesity-associated profile toward one resembling weight-loss programs.
Read the study Discussed in L-Glutamine for Gut Barrier Function -
Human obs.
Higher glutamine intake is associated with lower all-cause and cardiovascular mortality, with a larger reduction in all-cause mortality in people with diabetes.
Read the study Discussed in L-Glutamine for Gut Barrier Function -
Animal
In animal models of IBS, glutamine reduces intestinal permeability.
Read the study Discussed in L-Glutamine for Gut Barrier Function -
Animal
In Alzheimer's model mice, Bifidobacterium breve plus environmental enrichment eased amyloid-beta-induced cognitive impairment, likely via gut-microbiome changes to glutamine metabolism.
Read the study Discussed in Gut Microbiota and Alzheimer's Disease
Doses used in studies
Amounts reported in the research, not dosing recommendations.
| Dose | Context |
|---|---|
| 5 g/day | Typical recommended dose on glutamine powders; the dose she took for about two weeks |
| 15 g/day plus a low-FODMAP diet | More effective for IBS symptoms than low-FODMAP alone |
| 30 g/day for 14 days | Clinical trial showing a shift in gut microbiome composition |
| 12 g/day for 60 days | Older adults; no adverse effects noted |
| Up to 14 g/day | Study of amino acid supplement adverse effects found none up to this level |
Cautions
- Glutamine can be converted to glutamate and used by certain cancer cells for growth; anyone with cancer should talk with their doctor first (effects differ by tumor type).
- No adverse events reported up to 14 g/day, and none at 12 g/day for 60 days in older adults.