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Limited evidenceSleep & relaxation

Passionflower

Passiflora incarnata has a handful of small trials suggesting mild calming and modest subjective sleep benefit, but almost nothing at the scale or quality needed to call it effective. Treat it as a plausible mild relaxant, not a proven one.

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What the science says

  • Improves subjective sleep quality Limited evidence

    In a double-blind crossover trial in 41 healthy adults, one week of passionflower tea (2 g dried herb nightly) produced a small but statistically significant improvement in self-rated sleep quality versus placebo tea. Sleep-diary and actigraphy measures of sleep latency and total sleep time did not change, so the effect may be largely subjective.

  • Reduces anxiety Limited evidence

    A systematic review of Passiflora in neuropsychiatric disorders found only a small number of RCTs, mostly with fewer than 60 participants, short durations and heterogeneous extracts. Some pre-surgical and generalised-anxiety trials reported reductions comparable to low-dose benzodiazepines, but the studies are too small and too poorly replicated to support a firm claim.

  • Substitutes for benzodiazepines or manages withdrawal Limited evidence

    A few small trials have tested passionflower alongside or against oxazepam and clonidine, with mixed and largely unreplicated results. There is no evidence base supporting its use to taper prescribed anxiolytics, and doing so without medical supervision is unsafe.

Dosage & safety

Studied doseStudied doses range from 2 g of dried aerial parts brewed as tea before bed, to 400-800 mg/day of dried hydroalcoholic extract, to 45-60 drops/day of tincture. Pre-procedural anxiety trials used single doses of roughly 500-700 mg extract 30-90 minutes beforehand. Standardisation (usually to vitexin or total flavonoids) varies enormously between products.
SafetyCommon effects are drowsiness, dizziness and confusion, especially at higher doses; do not drive after taking it. Isolated case reports describe QT prolongation and ventricular arrhythmia, plus nausea and vomiting. Additive sedation with alcohol, benzodiazepines, antihistamines and Z-drugs. Avoid in pregnancy — Passiflora species have shown uterine-stimulant activity in animals — and in breastfeeding. Discontinue before surgery given the sedative interaction with anaesthesia.

How to take it

TimingTake it before bed, or 30-90 minutes before the event if you are using it for situational anxiety.
With food?Food makes no meaningful difference.
Worth knowingStandardisation varies enormously between products, so a dose that worked from one brand may do nothing from another.

Interactions

With medications

  • alcohol, benzodiazepines, Z-drugs and sedating antihistamines

    Additive sedation, dizziness and confusion. do not combine, and do not drive afterwards

  • general anaesthesia

    Additive sedation during and after the procedure. stop it before scheduled surgery and tell the anaesthetist

With other supplements

  • valerian, hops and other sedating herbs

    Additive drowsiness. add one at a time rather than starting a stack

Well-established interactions only — this is not a complete list. Always tell your doctor and pharmacist what you take.

Frequently asked questions

Does passionflower help you sleep?

The evidence is limited: one week of passionflower tea (2 g nightly) slightly improved self-rated sleep quality in 41 adults, but sleep latency and total sleep time did not change. The effect may be largely subjective.

Does passionflower work for anxiety?

Passionflower has only a few small, short anxiety trials with varied extracts, some reporting reductions comparable to low-dose benzodiazepines. The evidence is limited, so treat passionflower as a plausible mild relaxant, not a proven one.

Can passionflower replace benzodiazepines?

No: there is no evidence base supporting passionflower to taper prescribed anxiolytics, and doing so without medical supervision is unsafe. Passionflower also adds to the sedation of benzodiazepines, alcohol and Z-drugs.

What are the side effects of passionflower?

Passionflower can cause drowsiness, dizziness and confusion, so do not drive after taking it, and isolated case reports describe heart rhythm problems. Avoid it in pregnancy and breastfeeding, and stop it before surgery.

Scientific references

Where to buy

Nutricost, Passion Flower Extract, 1,500 mg, 120 Capsules

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