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.

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.

Scientific references

Passiflora incarnata in Neuropsychiatric Disorders-A Systematic Review
Janda K, Wojtkowska K, Jakubczyk K, et al. — Nutrients, 2020
A double-blind, placebo-controlled investigation of the effects of Passiflora incarnata (passionflower) herbal tea on subjective sleep quality
Ngan A, Conduit R — Phytotherapy Research, 2011

Where to buy

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

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