trans-Resveratrol, a plant compound from grape skins sold as a dietary supplement, is promoted for healthy aging as a way to copy the benefits of eating less. In people, the most consistent finding is a small reduction in waist size; other claimed effects are mixed. Generally well tolerated at moderate doses, it changes how the liver clears many medications, and some trials found it blunted fitness gains from training. (Full Review)
| Marker | Target | Why |
|---|---|---|
| ALT and AST | 7–56 U/L for ALT; 10–40 U/L for AST | Safety check; rose at 3 g/day |
| Creatinine | 0.7–1.3 mg/dL in men; 0.6–1.1 mg/dL in women | Safety check; kidney failure at 5 g/day in myeloma |
| HbA1c | 4.0–5.6% | Expected to change; most relevant in type 2 diabetes |
| Fasting glucose | 70–99 mg/dL | Expected to change; low values possible with glucose-lowering drugs |
| LDL cholesterol | No established target; track change from own baseline | Expected to change; effects small and inconsistent |
| INR (warfarin users only) | Prescriber-set range | Safety check; may shift via CYP2C9 inhibition |
| Blood pressure | No established target; track change from own baseline | Expected to change; effects mainly at 300 mg/day or more |
| Bone mineral density | No established target; track change in g/cm² from own baseline | Expected to change; DXA scan on the same machine |
Cadence: Baseline before starting; repeat at 6–8 weeks after starting or any dose increase, then every 6–12 months; INR at 1 week in warfarin users; bone density at 12–24 months