Naringenin, the sugar-free form of grapefruit's main bitter plant compound, is sold as a supplement for blood fats, liver fat and healthy aging. Two human trials from separate groups reported better blood fats, one also less liver fat; lifespan, muscle and brain claims rest on animal and cell studies. Short-term tolerance appears placebo-like; medicine interactions and missing long-term data are the main open questions. The evidence remains small and uncertain. (Full Review)
| Marker | Target | Why |
|---|---|---|
| LDL-C | <100 mg/dL | Expected to change: fell in the fatty liver trial |
| Triglycerides | <150 mg/dL | Expected to change: largest lipid response |
| HDL-C | ≥60 mg/dL | Expected to change: rose in the trial |
| ALT | Below 29–33 U/L (men) or 19–25 U/L (women) | Safety check; may fall as liver fat falls |
| AST | About 10–40 U/L | Safety check: liver or muscle injury |
| Fasting glucose | Not specified in the ER | Glucose marker, paired with fasting insulin |
| Fasting insulin | No established target; change from own baseline is tracked | Expected to change: fell in the case report |
| Interacting drug level (e.g., tacrolimus trough) | No established target; the drug's own therapeutic range applies | Safety check for narrow-margin CYP3A4 drugs |
| Liver imaging (ultrasound or elastography) | Not specified in the ER | Liver fat follow-up when starting with fatty liver |
Cadence: Baseline before starting; lipids, liver enzymes and glucose markers at 8–12 weeks, then every 6–12 months while use continues; drug levels rechecked 1–2 weeks after starting when interacting drugs are taken; liver imaging after 6–12 months with fatty liver at start. No change after 12 weeks at an adequate dose suggests non-response.