Is the passionflower in my garden the same thing?

Almost certainly not. The common garden vine in the UK is usually Passiflora caerulea, whereas the medicinal herb and nearly all the research is Passiflora incarnata.

Can I drink passionflower tea every night?

Evening tea is a traditional habit, and the tea trial lasted a week. Long-term data are limited, so it is worth checking first if you take regular medicines.

How does passionflower compare with valerian?

Both are traditional nervines and they are often combined, as in Sleep Deep. They are different herbs with their own evidence, and passionflower is generally considered the gentler of the two.

Can I take it with sleeping tablets or antidepressants?

Check with your GP or practitioner first. Passionflower may add to the effect of sedating medicines.

Passionflower: What It Is, How It Works, and When to Use It

Sarah Burt

Oct 14

6 min read

Passionflower (Passiflora incarnata) is the dried above-ground part of a climbing vine and a traditional nervine, a herb used to support a calm, settled nervous system. A 2020 systematic review of nine randomised trials found most reported lower anxiety after passionflower, and a small trial of passionflower tea found better self-rated sleep quality over a week. It is one of the herbs in the EarthWise Calm Nerve and Sleep Deep tonics.

Close-up of a purple and white passionflower blooming against a dark green leafy background.

What it is

Passionflower is a vigorous climbing vine native to the south-eastern United States, now grown in Europe and Asia too. The flower is remarkable: a lattice of fringed filaments around a central crown of stigmas. Spanish missionaries who met the plant in the 16th century read the flower as a symbol of the Passion of Christ, which gave it its name. The part used in herbal medicine is the dried leaf, stem and flower, known as the aerial parts.

Indigenous peoples of the Americas used it long before Europeans arrived, and it reached European gardens and herbals in the 17th century, where it became a standard nervine. Traditionally it is taken as an infusion of the dried herb or as a tincture, for restlessness, nervous tension and difficulty settling at night.

A buyer's note worth reading. Many plants are sold as passionflower, and they are not interchangeable. The hardy blue passionflower in UK gardens (Passiflora caerulea) and the passion fruit vine (Passiflora edulis) are different species. Almost all the clinical evidence is for Passiflora incarnata, so check the Latin name on the label.

How it is traditionally used

In Western herbal medicine, passionflower is classed as a nervine, a herb used to support the nervous system. It is traditionally used for tension, restlessness and the kind of mind that will not settle at night, and herbalists often pair it with skullcap, lemon balm, valerian or hops. Many traditional calming and sleep blends contain it.

It is usually taken as an infusion of the dried herb, as a tincture, or as a standardised extract in capsules. Herbalists tend to use lower, spread-out doses during the day for ongoing tension and a larger dose in the evening for sleep, which is one reason it appears in both a daytime formula and a night-time one in the EarthWise range.

The active compounds

Passionflower's key compounds are flavonoids, particularly the C-glycosyl flavones vitexin, isovitexin and orientin, along with small amounts of maltol and trace indole alkaloids. Standardised extracts are usually measured by total flavonoid content, expressed as vitexin. As with most herbs, the whole plant is more than any single compound.

The main proposed mechanism: GABA. GABA is the brain's main calming signal, and many sedative medicines act on its receptors. In laboratory and animal studies, passionflower extracts appear to act on the GABA system, and some flavonoids in the plant have been shown to bind GABA receptors. This could help explain the effects seen on tension and sleep. It is biologically plausible and often cited, but human confirmation is limited, so for now it is a proposed mechanism.

Other activity. Passionflower also shows antioxidant activity in laboratory studies. Direct human evidence for this is limited.

What the research shows

Passionflower has a long traditional record and a modest, mixed clinical one. Here is how it grades.

Evidence: anxiety. A 2020 systematic review (Nutrients) of nine randomised trials in adults, lasting from one day to 30 days, found that most reported lower anxiety after passionflower preparations, with the effect less clear in people with mild anxiety. No adverse effects were observed, including memory loss. A frequently cited pilot trial (Akhondzadeh and colleagues, 2001) gave 36 outpatients with generalised anxiety disorder either 45 drops a day of passionflower extract or the prescription medicine oxazepam for four weeks. Both groups improved with no significant difference at the end, although oxazepam acted faster and caused more problems with job performance.

Early evidence: sleep. In a double-blind crossover trial (Ngan and Conduit, 2011), 41 healthy adults aged 18 to 35 drank one cup of passionflower tea a day (2 g of dried herb) for a week, and a parsley tea placebo for another week. Self-rated sleep quality was better with passionflower by more than 5%. Sleep-lab measurements in a 10-person subgroup showed no significant change, so the benefit was one of perceived sleep quality.

Sarah's clinical perspective

I reach for passionflower when the picture is a busy, circling mind: the thought loop at bedtime, the mental chatter that carries on after the body is tired. It is why it appears in both Calm Nerve, for the daytime nervous system, and Sleep Deep, where it sits with valerian, lemon balm, lime flower, hops and lavender.

I find it works best alongside other herbs, and I like it because it is gentle enough to take regularly. As with all the nervines, I ask people to be sensible about driving and alcohol until they know how they respond.

Practical guidance

Dose. The tea trial used one cup a day made with 2 g of dried herb for a week, and the pilot anxiety trial used 45 drops a day of extract for four weeks. Other trials have used a range of extracts and tinctures. These are the amounts researchers used, not a dosing instruction for any particular product.

Format. Tea made from the leaf and flower, covered while it steeps for about ten minutes, is the traditional preparation. A tincture or standardised extract gives a more consistent dose. Check the label says Passiflora incarnata.

Time to effect. Some trials noticed an effect within days, though a steadier benefit tends to build with regular use over a few weeks.

Timing. For sleep, take it in the evening. It can cause drowsiness, so take care before driving until you know how it affects you.

What it does not replace. Passionflower supports a calm routine. It does not replace help for anxiety that is persistent or affecting daily life, or the basics of good sleep habits.

For how to take the EarthWise tonics specifically, the dose and full safety information are on each product page.

Common questions

Is the passionflower in my garden the same thing? Almost certainly not. The common garden vine in the UK is usually Passiflora caerulea, whereas the medicinal herb and nearly all the research is Passiflora incarnata.
Can I drink passionflower tea every night? Evening tea is a traditional habit, and the tea trial lasted a week. Long-term data are limited, so it is worth checking first if you take regular medicines.
How does passionflower compare with valerian? Both are traditional nervines and they are often combined, as in Sleep Deep. They are different herbs with their own evidence, and passionflower is generally considered the gentler of the two.
Can I take it with sleeping tablets or antidepressants? Check with your GP or practitioner first. Passionflower may add to the effect of sedating medicines.

Where passionflower appears in the EarthWise range

Passionflower is one of the four herbs in Calm Nerve, Sarah's nervous-system formula, where it sits with Skullcap, Lemon Balm and Ashwagandha.

It also appears in Sleep Deep, alongside Valerian, Lemon Balm, Lime Flower, Hops and Lavender, herbs traditionally used to support relaxation and healthy sleep patterns.

If you are not sure which formula fits, the EarthWise health quiz is the best place to start. Full safety information is on each product page.

When to seek professional support

Passionflower is well tolerated in the trials so far, with no serious adverse effects reported. Check with a practitioner first in these situations:

Pregnancy and breastfeeding. It is not recommended. Some constituents have been suspected of stimulating the uterus, and safety data are limited.
Sedatives, sleeping tablets, anti-anxiety medicines or antidepressants. Passionflower may add to their effect, so speak to your GP or practitioner first.
Driving and alcohol. It may cause drowsiness, and combining it with alcohol or other sedating substances can add to the effect.
Planned surgery. Tell your surgical team and stop at least two weeks beforehand unless advised otherwise, because it may add to the effect of anaesthetics.

Sarah Burt is a registered naturopath, medical herbalist and iridologist with 25+ years of clinical experience. All EarthWise tonics are formulated by Sarah based on her clinical protocols.

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This article is for informational purposes only and is not intended to diagnose, treat or cure any health condition. Always consult a qualified health practitioner before making changes to your health regimen.