Passionflower: What the Research Shows and How to Use It
Passionflower (Passiflora incarnata) is a climbing plant with beautiful purple flowers. Its leaves, stems and flowers have long been used in teas and extracts by people who want to unwind or fall asleep more easily.
In this article you will learn what the research shows, how to understand extract strength on the label and when it is better to avoid passionflower.
In brief. Passionflower (Passiflora incarnata) is a plant that people choose for calmer evenings and relaxation, and scientists have been studying it for several years.¹ So far there are few studies, and they are small, so the effect may differ from person to person.² Passionflower may cause drowsiness. If you take sedatives or sleeping medicines, talk to your doctor before you start taking passionflower.³
What is passionflower?
Supplements most often use the aerial parts of passionflower: the leaves, stems and flowers. They contain flavonoids, such as vitexin.4
In some EU countries, passionflower preparations are registered as traditional herbal medicinal products to relieve mild symptoms of mental stress and to help with falling asleep. This registration is based on long-standing use rather than large clinical studies.4 Food supplements are not medicines and cannot be intended to treat diseases.
What does the research show?
Sleep. In one study, 41 adults drank either passionflower tea or placebo tea every evening for a week. Those who drank passionflower tea rated their sleep quality slightly better.5 This was a small and short study.
Anxiety. A review found only 2 suitable studies with 198 participants. This was not enough to draw firm conclusions.2
What this means for you. Passionflower may be a gentle choice for an evening ritual, but you should not expect a strong or guaranteed effect. If anxiety or insomnia lasts longer, see a doctor.
How to read the label
Passionflower products differ greatly in strength. That is why it is important to look at more than just the milligrams.
| What you see on the label | What it means |
|---|---|
| "Extract 6:1" | 1 part of extract is made from 6 parts of dried herb. For example, 250 mg of extract corresponds to 1,500 mg of herb. |
| "Liquid extract 1:1" | 1 ml of liquid corresponds to 1 g of dried herb. |
| "Standardised, min. 3.5% vitexin" | A certain amount of flavonoids is ensured in every batch. |
Example. A 250 mg "6:1" capsule and 1 ml of "1:1" liquid extract look very different. However, the first gives you the equivalent of 1.5 g of herb, the second 1 g.
When is it better to avoid passionflower?
- You are pregnant or breastfeeding – there is not enough safety data, and high doses may cause uterine contractions.34
- You take sedatives, sleeping medicines or anti-anxiety medicines.4
- You have surgery coming up – passionflower may enhance the effect of anaesthetics.3
- Children under 12 years of age. Research results are insufficient.4
Possible side effects include drowsiness, dizziness and impaired attention.3 After taking passionflower, do not drive until you know how it affects you.4
Selected passionflower products
Commercial information. These are products available in our shop. This is not a ranking of effectiveness. Before buying, check the ingredients and directions for use on the product page.
Passiflora, 250mg - 120 vegan capsules - Osavi
250 mg of passionflower extract (6:1) per capsule, standardised to at least 3.5% vitexin. This corresponds to 1,500 mg of herb. Take 1 capsule per day after a meal.6
Passion Flower, 350mg - 90 vcaps - NOW Foods
Extract of passionflower flowers and aerial parts, 700 mg in two capsules, standardised to at least 3.5% flavonoids. Check the directions for use on the product page.7
Passion Flower Liquid Extract - Passion Flower Extract - 29.6 ml - Swanson
Liquid passionflower extract with vegetable glycerine, alcohol-free. One serving is 1 ml (about 28 drops); the manufacturer recommends taking it 3 times per day with a small amount of water.8
Passionflower Aerial Parts - 30 ml - Nature's Answer
Liquid extract of passionflower aerial parts 1:1, where 1 ml corresponds to 1 g of dried herb. The manufacturer recommends 1–2 ml 3 times per day. Shake well before use.9
Frequently asked questions
Can passionflower be combined with melatonin?
Both may cause drowsiness, so it is better to discuss the combination with a doctor or pharmacist. We write more about melatonin in the article "Melatonin".
Does passionflower tea work the same way as capsules?
In tea, the amount of active substances depends on the amount of herb and the steeping time, so it is usually weaker and less precise than a standardised extract.
When is the best time to take passionflower?
If you choose passionflower for sleep, it is usually taken in the evening. Follow the dose and timing given by the manufacturer.
Scientific sources
- European Commission. EU Register of nutrition and health claims made on foods. ec.europa.eu
- Miyasaka LS, Atallah AN, Soares BG. Passiflora for anxiety disorder. Cochrane Database Syst Rev. 2007;(1):CD004518. doi:10.1002/14651858.CD004518.pub2
- NIH National Center for Complementary and Integrative Health. Passionflower. nccih.nih.gov
- European Medicines Agency, HMPC. European Union herbal monograph on Passiflora incarnata L., herba. ema.europa.eu
- 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;25(8):1153–1159. doi:10.1002/ptr.3400
- Osavi. Passiflora, 250 mg, 120 capsules. Product label.
- NOW Foods. Passion Flower, 350 mg, 90 capsules. Product label.
- Swanson. Passion Flower Liquid Extract, 29.6 ml. Product label.
- Nature's Answer. Passionflower Aerial Parts, 30 ml. Product label.
Disclaimer. This article is for information purposes only and does not replace advice from a doctor or pharmacist. Food supplements are not intended to treat or prevent diseases and are not a substitute for a varied diet and a healthy lifestyle. Before taking supplements, especially during pregnancy or breastfeeding, if you have a chronic condition or if you take medicines, consult a healthcare professional.
