Passionflower Tea and Sleep: What Studies Show
Passionflower has been brewed as an evening tea for generations. It’s often grouped with chamomile and valerian as a “wind-down” herb. But how much research is there, and does any of it involve an actual cup of tea? This guide looks at what’s been studied and how much weight it can bear.
What is passionflower?
The passionflower used in herbal teas is Passiflora incarnata, a climbing vine native to the south-eastern United States. It’s a relative of the passionfruit vine many Australians grow in the backyard (Passiflora edulis), but it’s a different species. The striking flowers led Spanish missionaries to name it after the Passion story.
Indigenous peoples of North America used the plant long before Europeans arrived. It later became part of European and American herbal traditions. For tea, the dried leaves, stems and flowers (the “aerial parts”) are used.
What’s in it?
Passionflower contains a range of plant compounds, especially flavonoids such as vitexin, isovitexin and chrysin, along with small amounts of other compounds. Lab and animal research has looked at how some of these interact with the brain’s GABA system, which is involved in calming nerve activity. As always, effects in the lab don’t automatically carry over to people drinking tea.
The tea trial: Ngan 2011
Most herbal research uses extracts. A 2011 Australian study in Phytotherapy Research is one of the few that tested the tea itself (Ngan & Conduit, 2011).
Forty-one healthy adults with mild, occasional sleep problems drank a cup of passionflower tea each evening for a week, and a placebo tea (parsley) for another week, without knowing which was which. They kept sleep diaries, and some also had their sleep measured with a recording device.
On the sleep diaries, people rated their sleep quality as slightly better during the passionflower week. But other measures, including how long it took to fall asleep and the recorded sleep data, didn’t differ meaningfully. The study was small and short, and the overall result was modest. It’s an interesting starting point, not proof.
What Cochrane found
The Cochrane Collaboration looked at passionflower for anxiety disorders, a related area (Miyasaka et al., 2007). The reviewers could find only two randomised trials, with fewer than 200 people in total, and both had important limitations.
Their conclusion was that there were too few studies to draw any conclusions about whether passionflower works for anxiety. They called for larger, better-designed trials.
A more recent review
A 2020 systematic review in Nutrients gathered a broader range of studies on Passiflora incarnata and the nervous system, including sleep, anxiety and other areas (Janda et al., 2020). The authors found that some trials reported positive results. However, the studies differed widely in the preparations and doses used, and many were small. They concluded that more high-quality research is needed before passionflower’s role can be confirmed.
Reading between the lines
Put together, passionflower is a herb with a long traditional history and a handful of small, sometimes encouraging studies. It’s not a herb with strong evidence. Honest summaries of the research tend to use words like “preliminary” and “limited”, and that’s the right way to think about it.
If you have ongoing trouble sleeping, it’s worth talking to your GP. Poor sleep can have many causes, and some need proper assessment.
Brewing a cup
If you enjoy passionflower as part of an evening routine, here’s a simple way to brew it:
- Use about 1 teaspoon of dried herb per cup.
- Pour over freshly boiled water. Unlike green tea, herbal infusions are fine with boiling water.
- Cover and steep for 5–10 minutes, then strain.
- It has a mild, grassy, slightly earthy taste. Some people like it with a little honey or blended with other herbs.
Part of the appeal of any bedtime tea may be the ritual itself: slowing down, switching off screens and sitting with something warm.
Who should take care?
Passionflower may add to the effects of sedative medicines, sleeping tablets or alcohol, and may cause drowsiness. Don’t drive or operate machinery if it makes you sleepy. It isn’t recommended during pregnancy or breastfeeding, as there’s not enough safety information, and it should be stopped before surgery. If you take regular medication, check with your pharmacist.
The bottom line
Passionflower tea is a gentle, traditional evening drink with a little research behind it. One small trial of the tea found a slight improvement in self-rated sleep quality, but reviews agree the evidence is still too limited for firm conclusions. Enjoy it as part of a relaxing routine, and see your GP for persistent sleep problems.
This article is general information only and is not medical advice. It is not about any specific product. Talk to your GP or pharmacist about your own health.
References
- Ngan A, Conduit R. A double-blind, placebo-controlled investigation of the effects of Passiflora incarnata (passionflower) herbal tea on subjective sleep quality. Phytother Res. 2011. https://pubmed.ncbi.nlm.nih.gov/21294203/
- Miyasaka LS, Atallah AN, Soares BG. Passiflora for anxiety disorder. Cochrane Database Syst Rev. 2007. https://pubmed.ncbi.nlm.nih.gov/17253512/
- Janda K, et al. Passiflora incarnata in neuropsychiatric disorders: a systematic review. Nutrients. 2020. https://pubmed.ncbi.nlm.nih.gov/33352740/
