Passionflower is a dried plant preparation, sold as capsules, liquid extract and tea for nervous tension and poor sleep. Its clearest effect is a single dose before a stressful event: calming without next-day dullness, memory gaps or dependence. Sleep gains are modest, and benefit for long-standing anxiety is unsettled. It adds to anything else that sedates, and most tested supplements did not match their labels. (Full Review)
| Marker | Target | Why |
|---|---|---|
| QTc interval | Under 430 ms (men), under 440 ms (women) | Screens the one serious cardiac signal reported |
| Serum potassium | 4.2–4.6 mmol/L | Low potassium lengthens repolarization independently |
| Serum magnesium (red blood cell) | 5.0–6.5 mg/dL | Low magnesium compounds any repolarization effect |
| ALT | 10–26 U/L (men), 10–19 U/L (women) | Confirms no unexpected liver effect from a multi-herb product |
| Insomnia Severity Index | Under 8 | The primary success measure for the sleep goal |
| GAD-7 anxiety score | 4 or below | The primary success measure for the anxiety goal |
| Sleep efficiency (time asleep as a share of time in bed, by wearable or diary) | 88–92% | Tracks the objective sleep endpoint that moved in trial |
Cadence: Symptom scores at 2 weeks and 4 weeks, then every 3 months while use continues; the electrocardiogram is repeated only if the dose rises or a QT-prolonging drug is added, and liver enzymes are rechecked annually.