Thiamine (vitamin B1) is an essential B vitamin that helps the body turn food into energy, sold as a dietary supplement to prevent and reverse deficiency. Its record against deficiency diseases of the heart, nerves and brain is long and secure; its clearest value is protecting adequate levels with heavy drinking, weight-loss surgery, diabetes or certain heart and diabetes medications. Evidence beyond correction is modest. Safety is a strength. (Full Review)
| Marker | Target | Why |
|---|---|---|
| Whole-blood thiamine diphosphate | 70–180 nmol/L | Confirms status and dose response |
| Erythrocyte transketolase activity coefficient | Below 1.15 | Functional test of thiamine status |
| Serum magnesium | 0.70–1.00 mmol/L | Safety check: low values change use (magnesium added) |
| Urine albumin-to-creatinine ratio (diabetes only) | No established target; track change from own baseline | Urinary albumin fell with thiamine in diabetes |
Cadence: Baseline before any supplement; thiamine diphosphate 4–8 weeks after starting a therapeutic or high-dose regimen, then every 6–12 months; magnesium at the same timepoints if low; urine albumin every 3–6 months in diabetes