Passionflower is sold for anxiety and sleep, and PubMed holds 332 records on the species used in supplements. Only 23 of them are clinical trials, and most test something few buyers ever do.
That gap, between what was tested and what is sold, is what this guide is about.
Quick Answer: What Is Passionflower?
Passionflower (Passiflora incarnata) is a climbing vine native to the southeastern United States, sold as a calming herb for anxiety and sleep. It is not the passion fruit plant. PubMed holds 332 records on it and 23 clinical trials. Seven single-herb trials test 1 dose before a procedure. Everyday anxiety rests on 1 trial of 36 people.
Key Takeaways
- Passiflora incarnata is 1 species; passion fruit is a different one.
- PubMed holds 332 records on passionflower and 23 clinical trials.
- 7 of about 11 single-herb trials test 1 dose before a procedure.
- Everyday anxiety rests on 1 trial of 36 outpatients over 4 weeks.
- It stacks with alcohol and sedatives, and pregnancy is 1 clear avoid.
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Which Plant This Actually Is
The name passionflower covers a whole genus of vines, and only 1 of them is the calming herb. Getting the species right is the first quality check.
- Passiflora incarnata: The supplement species, also called maypop or purple passionflower.
- What it looks like: A purple and white flower with a fringe of fine corona filaments.
- Passiflora edulis: The passion fruit plant, grown for food.
- Passiflora caerulea: The blue crown passionflower, an ornamental.
The mix-up matters because fruit dominates the research. PubMed holds 1,062 records on passion fruit and 332 on the supplement species, so a study on Passiflora is not automatically a study on passionflower.
Most of what gets quoted about the supplement comes from anxiety research, and it is set out in what the anxiety trials actually tested.
The Size of the Evidence
Everyone who writes about passionflower says the evidence is limited. These counts say how limited, and anyone can rerun them.
| What PubMed holds on passionflower | Count |
|---|---|
| Records mentioning any Passiflora species | 1,207 |
| Records on passion fruit, Passiflora edulis | 1,062 |
| Records on Passiflora incarnata or passionflower | 332 |
| Of those, tagged as human | 121 |
| Randomized or clinical trials | 23 |
| Systematic reviews or meta-analyses | 16 |
| Case reports | 8 |
Reading all 23 trial abstracts changes the picture again. Several are multi-herb blends, 1 is a protocol and 1 is about passion fruit. About 11 test passionflower on its own.
| Single-herb passionflower trials, by question | Trials | People |
|---|---|---|
| One dose before surgery or a dental extraction | 7 | 464 |
| Everyday generalized anxiety, over 4 weeks | 1 | 36 |
| Sleep, over 1 to 2 weeks | 2 | 151 |
| Opiate withdrawal, alongside clonidine | 1 | 65 |
Seven of those 11 give a single dose shortly before a dental extraction or an operation. That is a real finding, and it is not how anyone uses a bottle at home.
What the Best Trials Tested
The pre-procedure trials are the strongest part of this literature, so they deserve an accurate description.
- Design: Randomized, mostly double-blind, 1 oral dose.
- Timing: 30 to 90 minutes before surgery or a tooth extraction.
- Comparator: Placebo, or midazolam, a benzodiazepine.
- Size: 20 to 200 people per trial, 464 in total.
In 60 day-surgery patients, 500 mg taken 90 minutes beforehand lowered anxiety scores without extra sedation.[1]Preoperative oral Passiflora incarnata reduces anxiety in ambulatory surgery patients: a double-blind, placebo-controlled study — Anesthesia and Analgesia (2008) View source In 200 people having wisdom teeth removed, it performed like midazolam and better than placebo.[2]Herbal medicines as anxiolytics prior to third molar surgical extraction. A randomized controlled clinical trial — Clinical Oral Investigations (2021) View source
Everyday anxiety is thinner: 1 pilot of 36 outpatients found an extract and oxazepam no different after 4 weeks.[3]Passionflower in the treatment of generalized anxiety: a pilot double-blind randomized controlled trial with oxazepam — Journal of Clinical Pharmacy and Therapeutics (2001) View source Sleep has less still, as what the two sleep trials measured shows.
Three Reviews, Three Readings
The same small pool of trials has been reviewed several times, and the conclusions do not line up.
| Review | Year | Reading |
|---|---|---|
| Cochrane review | 2007 | 2 trials, 198 people, too few to permit any conclusions |
| Psychiatric herbal medicine review | 2018 | High-quality evidence for anxiety disorders |
| Network meta-analysis | 2022 | Estimate did not reach statistical significance |
Cochrane found only 2 eligible studies and declined to conclude anything.[4]Passiflora for anxiety disorder — Cochrane Database of Systematic Reviews (2007) View source A 2018 review graded passionflower among the best-supported anxiety herbs.[5]Herbal medicines in the treatment of psychiatric disorders: 10-year updated review — Phytotherapy Research (2018) View source
A 2022 network analysis of 29 trials put its effect just short of significance.[6]Medicinal herbs for the treatment of anxiety: A systematic review and network meta-analysis — Pharmacological Research (2022) View source
How It Is Thought to Work
The proposed mechanism explains both the interest and the caution.
- Target: GABA receptors, the brain's main calming signal.
- Same system as: Benzodiazepines and many sleeping pills.
- Status: Plausible, and incompletely understood.
- Consequence: Its effect may add to other sedatives.
A 2021 review concluded that herbal extracts may act partly through GABA receptors, and that the mechanism is not completely understood.[7]Herbal Remedies and Their Possible Effect on the GABAergic System and Sleep — Nutrients (2021) View source That shared system is why the rules in who should avoid passionflower matter.
Why It Is Not a Casual Supplement
A herb that may act on the same system as sedative drugs needs a short list of rules.
- Alcohol: Both slow the nervous system, so do not combine them.
- Sedatives: Benzodiazepines, sleeping pills and opioids need a prescriber's view.
- Other herbs: Valerian, kava and hops may add to the effect.
- Driving: Wait until you know how it affects you.
- Pregnancy: Avoid it entirely.
NCCIH lists drowsiness, dizziness and confusion as possible side effects, and says it should not be used in pregnancy because it may induce uterine contractions.[8]Passionflower: Usefulness and Safety — National Center for Complementary and Integrative Health View source
Who It Might Suit
On this evidence, passionflower is a modest, short-term option for adults. It is not a treatment.
- Reasonable: An adult with occasional tension who takes no other sedatives.
- Reasonable: Short courses, inside NCCIH's 8-week window for extracts.
- Not reasonable: Anyone pregnant, or drinking in the evening.
- Not reasonable: A swap for prescribed anxiety or sleep medication.
On those terms a 1000 mg passionflower capsule is a measured amount of 1 herb, sold without a treatment claim.
Speak to a Clinician Before Taking Passionflower If
- You take a benzodiazepine, a sleeping pill, an opioid or another sedating prescription
- You drink alcohol in the evening, or need to drive after taking it
- You already take valerian, kava, hops or another sedating herb
- You are pregnant, trying to conceive or breastfeeding
- You have surgery or a dental procedure with sedation within 2 weeks
Frequently Asked Questions
What does passion flower do for the body? +
It is used as a calming herb. Small trials suggest it can lower anxiety before a procedure, and 1 trial of 110 people found about 23 more minutes of sleep.
Is passionflower a strong sedative? +
Not at the doses trialled. Two pre-surgery trials of 60 patients each found no change in psychomotor tests, but it can still add to alcohol and sedatives.
Does passion flower increase estrogen? +
None of the 11 single-herb passionflower trials measured estrogen. There is 0 human evidence that it raises it.
What is the strongest herb for anxiety? +
No herb has settled that. A 2022 network meta-analysis of 29 trials and 12 herbs found passionflower's estimate fell short of significance.
How does passionflower affect the brain? +
It is thought to act on GABA receptors, the system benzodiazepines use. A 2021 review says the mechanism is not completely understood.
Is passionflower the same as passion fruit? +
No. Passion fruit is Passiflora edulis, with 1,062 PubMed records, against 332 on the supplement species, Passiflora incarnata.
Is passionflower safe? +
NCCIH says extract taken daily may be safe for up to 8 weeks, and tea for up to 7 nights. Drowsiness, dizziness and confusion are possible.
Can passionflower replace anxiety medication? +
No. The benzodiazepine comparisons were single doses before dental surgery, plus 1 pilot of 36 people. Never stop a prescription without your prescriber.
Can I take passionflower while pregnant? +
No. NCCIH says it should not be used in pregnancy because it may induce uterine contractions. That is 1 of the firm rules here.
Is passionflower approved by the FDA? +
No. Like every dietary supplement it is not approved by the FDA before sale, and 0 supplements are reviewed for efficacy that way.
Related Reading
- Passionflower Dosage and Timing
- Capsules or Tincture: Which Format
- Passionflower Compared With Valerian
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