Naringin, the bitter compound of grapefruit and pomelo, is an inexpensive dietary supplement used for fat and sugar handling, blood vessel health and longevity, largely based on animal studies. Small human trials suggest modest cholesterol and body weight improvements in people with abnormal blood fats, but the largest trial found no cholesterol change. Safety looks favorable within the doses studied; the main concern is reduced absorption of certain medications. (Full Review)
| Marker | Target | Why |
|---|---|---|
| LDL cholesterol | <100 mg/dL; <70 mg/dL with high cardiovascular risk | Main outcome in naringin trials |
| ApoB | <80 mg/dL; <60 mg/dL for high risk | Counts artery-clogging particles |
| Triglycerides | <100 mg/dL | Rounds out the lipid response |
| Fasting glucose | 75–90 mg/dL | Tracks claimed glucose effects |
| HbA1c | <5.4% | Three-month glucose average |
| ALT and AST | <25 U/L each | Liver fat response and safety |
| hs-CRP | <1.0 mg/L | Systemic inflammation |
| TSH (levothyroxine users) | 0.5–2.5 mIU/L | Detects reduced levothyroxine absorption |
| QTc (on electrocardiogram) | <440 ms (men); <450 ms (women) | Checks for flavonoid-related QT lengthening |
| Pulse wave velocity (optional) | No established functional target; track change from own baseline | Arterial stiffness outcome from the grapefruit trial |
Cadence: Baseline before starting; at 8–12 weeks, then every 6–12 months while use continues. TSH 6–8 weeks after starting or stopping (levothyroxine users); electrocardiogram at 2–4 weeks (QT-prolonging drugs).