Green tea extract concentrates the tea leaf's antioxidants into a daily dose. Its most consistent benefit is a small drop in cholesterol, with lighter signals for blood sugar, blood pressure, and body fat—strongest in people who start with less-than-ideal numbers. Rare liver injury from high doses, especially on an empty stomach, is the main safety concern. (Full Review)
| Marker | Target | Why |
|---|---|---|
| ALT | ~10–25 U/L (women); ~10–30 U/L (men) | Detects early liver injury from the extract |
| AST | ~10–26 U/L | Complements ALT in detecting liver stress |
| Lipid panel | LDL <100 mg/dL; triglycerides <90 mg/dL | Tracks the best-supported benefit |
| HbA1c and fasting glucose | HbA1c <5.4%; fasting glucose 75–90 mg/dL | Tracks the glycemic effect |
| Ferritin and iron studies | Ferritin ~50–150 ng/mL | Guards against catechin-driven iron depletion |
| hs-CRP | <1.0 mg/L | Gauges any anti-inflammatory effect |
Cadence: Liver enzymes at baseline and ~8–12 weeks after starting a high-dose extract; cardiometabolic markers at baseline, ~3 months, then every 6–12 months.