Passionflower: Studies on tension and sleep

Inner restlessness, tension and sleepless nights are constant companions for many people. Demand for gentle, plant-based alternatives to chemical sedatives is steadily increasing. Passionflower (Passiflora incarnata) has long been regarded as a well-established remedy for nervousness and sleep problems. But what does current science say? And what should be considered when using it? A recent analysis by the University of Münster provides important findings – especially on the crucial question of product quality.

The plant with the symbolic name

Passionflower, more precisely maypop passionflower (Passiflora incarnata), is a climbing plant originally native to the warm regions of South and North America. It owes its name to Christian missionaries, who recognised symbols of the Passion of Christ in its striking flowers. Today, it is mainly cultivated for medicinal purposes on plantations in India, the USA and South America. As an ornamental plant, however, it is also found in many gardens in Europe.

The part used is passionflower herb (Passiflorae herba), meaning the above-ground parts of the plant. The European Pharmacopoeia specifies a minimum flavonoid content for the herbal drug – for ethanolic or methanolic extracts, this is at least 2.0 percent.

Mechanism of action: how passionflower affects the psyche and nervous system

The calming effect of passionflower takes place in the central nervous system. According to current research, it is assumed to act through modulation of the GABA system. GABA (gamma-aminobutyric acid) is the most important inhibitory neurotransmitter in the brain – simply put, the “braking messenger” responsible for relaxation and calming. Passionflower extract may probably increase the concentration of GABA or enhance its effect.

The exact active constituents responsible for its effect have not yet been fully clarified. However, research assumes that flavonoids in particular, especially benzoflavone compounds, play a central role. Glycosides have sedative and anxiolytic effects, while coumarin derivatives have antispasmodic properties. Antioxidant effects have also been demonstrated.

Areas of use: what is scientifically recognised?

Nervous restlessness

The central area of use for passionflower is the treatment of nervous restlessness. The German Commission E of the Federal Health Office recognised this indication years ago. Passionflower dry extract is also officially approved in Germany as a herbal medicinal product for this indication.

Anxiety and tension

Several clinical studies support the anxiolytic effect of passionflower. A frequently cited controlled study from 2001 compared passionflower extract with the benzodiazepine oxazepam in patients with generalised anxiety disorder. The result: after seven days of use, passionflower extract showed a comparable anxiety-reducing effect to the chemical sedative – with significantly less impairment in everyday working life. Only the onset of action was faster with oxazepam.

Passionflower has also shown convincing results in situational anxiety, for example before surgery. In a placebo-controlled study with 60 patients who received spinal anaesthesia before an operation, anxiety was statistically significantly lower 30 minutes after administration of the extract compared with the placebo group. An earlier study had already produced similar results.

Sleep disorders

For sleep disorders, the evidence is somewhat more limited, but promising. A placebo-controlled double-blind study with 41 adults suffering from mild sleep disturbances examined the effect of a passionflower tea preparation over one week. The result: subjective sleep quality improved significantly in the passionflower group compared with placebo.

Here, passionflower acts through its anxiolytic component – meaning that it reduces the tension that often prevents falling asleep and can therefore make it easier to fall asleep. In practice, it is therefore often used for mild difficulties falling asleep and sleep disorders related to nervousness.

Further possible uses

Traditionally, passionflower is also used for the following complaints, although the scientific evidence here is less extensive:

• Nervous gastrointestinal complaints: Due to its relaxing effect on the autonomic nervous system, it may help with irritable bowel syndrome or nervous stomach.
• Menopausal complaints: It does not act directly on hormone balance, but may ease typical symptoms such as inner restlessness and sleep disorders during this phase of life. Its anxiolytic effect may also indirectly influence hormonally related states of restlessness by reducing stress-related cortisol release.
• Muscle tension and cramps: Its antispasmodic properties may provide support for menstrual cramps or muscle tension.

The quality problem: medicinal product vs. food supplement

A recent analysis by the University of Münster, published in the Zeitschrift für Phytotherapie in 2025, revealed alarming findings. A research team led by Alexa Brouns examined six food supplements and five medicinal products containing passionflower herb from Germany.

The results are clear:

• Five of the six food supplements were problematic: the marker flavonoid was either not detectable or only weakly detectable. The authors classified these products as counterfeits and food fraud – in their assessment, they are not marketable.
• Only one food supplement from the USA and all five medicinal products showed full agreement with the reference chromatogram. Only in these products was the content therefore actually consistent with the label.

There were also clear quantitative differences: the EMA recommends a daily intake of 10–80 mg flavones, corresponding to 1–8 g of plant material. All medicinal products met this recommendation, providing between 50 and over 123 mg per day. The only marketable food supplement provided just 16 mg of flavones with two capsules – a very low amount.

Use and dosage

Food supplements

Passionflower extract is also available as a food supplement, often in combination with other calming plant compounds. When choosing a food supplement, the quality of the extract is crucial – as the University of Münster study shows, the actual active compound content varies considerably. Look for standardised extracts with a stated vitexin content, as well as GMP-certified manufacturing and laboratory-tested batches.

Tea preparation

For a tea, pour boiling water over about 2 grams, or one teaspoon, of finely cut herb and leave to steep for 10–15 minutes. Two to three cups can be consumed throughout the day or before going to bed.

Tincture

To make a homemade tincture, the dried leaves are covered with alcohol and kept sealed for four weeks. After straining, up to ten drops may be taken three times daily.

Side effects and contraindications

Passionflower is considered well tolerated in therapeutic dosages. Nevertheless, occasional side effects may occur:

• Dizziness, drowsiness
• Nausea, gastrointestinal complaints
• Confusion, drowsiness
• Allergic skin reactions, rarely

Important contraindications:

• Pregnancy and breastfeeding: Use is not recommended, as passionflower in larger amounts may stimulate the uterus and trigger premature contractions.
• Interactions: Concurrent use with benzodiazepines, such as lorazepam, or other substances acting on the central nervous system should only take place after medical consultation. One case report describes overstimulation with trembling when lorazepam was combined with passionflower and valerian.
• Children: Use in children should be medically supervised.

Conclusion

Passionflower is a valuable medicinal plant for the gentle treatment of nervous restlessness, tension and mild sleep disorders. The scientific evidence for its anxiolytic effect is good, while the evidence for its sleep-promoting effect is promising.

The crucial point in practice is quality: the recent study by the University of Münster clearly shows that many food supplements are deficient or even counterfeit. Anyone wishing to benefit from its effect should therefore rely on registered medicinal products from pharmacies. In these products, the content of active flavonoids is guaranteed and corresponds to the requirements of the European Medicines Agency.

In combination with other calming measures such as relaxation techniques or improved sleep hygiene, passionflower can therefore make an important contribution to greater inner balance and restful sleep.

Official sources & studies

• Brouns A et al.: Qualitätsvergleich von Passionsblumen-Produkten (Zeitschrift für Phytotherapie 2025; 46: 225-233) – Medical Tribune

• Pflanzliche Sedativa – Enzyklopädie der Schlafmedizin (SpringerMedizin, 2024)

• Passionsblume – Arzneipflanzengarten der Universität Kiel

• Akhondzadeh S et al.: Passionflower in the treatment of generalized anxiety (Journal of Clinical Pharmacy and Therapeutics, 2001)

• Aslanargun P et al.: Passiflora incarnata Linneaus as an anxiolytic before spinal anesthesia (Journal of Anesthesia, 2012)

• Ngan A, Conduit R.: A double-blind, placebo-controlled investigation of the effects of Passiflora incarnata (Passionflower) on sleep in adults (Journal of Sleep Research, 2011)