Glutamine is an amino acid the body makes, sold as a powder for gut and recovery support. Gains are clearest where that supply is drained: the gut lining after infection, mouth and throat during cancer treatment. Fasting glucose and an inflammation marker improve modestly. Claims for muscle size and athletic performance are unsupported; everyday doses are well tolerated. (Full Review)
| Marker | Target | Why |
|---|---|---|
| Plasma glutamine | 500–750 µmol/L | Marks the depleted state where trials found benefit |
| High-sensitivity C-reactive protein | Below 0.5 mg/L | Tracks the inflammation endpoint that pooled trials moved |
| Fasting glucose | 70–85 mg/dL | Tracks the fasting glycemic endpoint of the pooled trials |
| Glycated hemoglobin | Below 5.3% | Confirms the glucose change is a sustained shift |
| Estimated glomerular filtration rate | Above 90 mL/min/1.73 m² | Screens the clearance behind the kidney-injury report |
| Blood urea nitrogen | 10–16 mg/dL | Detects rising nitrogen load before creatinine moves |
| Alanine aminotransferase | Below 20 U/L (18 women) | Screens liver capacity to clear the ammonia load |
| Fasting plasma ammonia | Below 30 µmol/L | Direct check on the encephalopathy mechanism |
| Lactulose-to-mannitol ratio | Change vs. own baseline | Quantifies the barrier defect that predicts response |
Cadence: Repeat panel at 8–12 weeks, at 6 months, then annually; the 8-week check applies over age 60, filtration rate below 90, or above 20 g daily