← The FormularyAfter hoursPassion flower
Also known as Passiflora incarnata; maypop; purple passionflowerTwenty-three extra minutes, if the trial holds.
Passion flower has the widest gap in this category between how confidently it is sold and what has actually been shown. Cochrane reviewed it for anxiety in 2007, found two usable randomised trials covering 198 people between them, neither of which compared it against placebo, and concluded the trials were too few in number to permit any conclusions at all. Since then the strongest sleep trial — 110 adults with DSM-5 insomnia disorder, two weeks, overnight polysomnography — found total sleep time rose 23 minutes more than placebo at p=0.049. Look at the spread around that figure: the standard deviation was 54 minutes, more than twice the effect. It is a real result sitting exactly on the edge of significance in a very noisy measurement, and in the same trial sleep efficiency and wake-after-sleep-onset improved from baseline but not against placebo. The famous tea study found better subjective sleep ratings in healthy adults with mild sleep fluctuations — not people with insomnia — and no objective difference in the ten participants who were actually wired up. That is the honest state of the evidence. The trials that found anything used 500 mg or more of extract, or a teabag. OUT has 100 mg. DOWN has 25 mg. What I would tell a friend: it earns its place as a traditional wind-down herb and it does not earn a claim. And if you take anything that affects your heart rhythm, or any serotonergic medicine, skip it entirely.
The above-ground parts — leaf, stem, tendril and flower — of Passiflora incarnata, a North American climbing vine with an unmistakable fringed purple corona.
Nobody has pinned this one down, which is unusual for a plant used this widely for this long. Three candidate mechanisms run in parallel. The beta-carboline alkaloids harman and harmine inhibit monoamine oxidase in vitro, though they are present in the herb at very low concentrations. Maltol and related gamma-pyrone derivatives appear to act at GABA receptors. The flavone chrysin shows central nervous system depressant activity in animal models. Fractionation work has repeatedly failed to isolate a single responsible constituent, and some of it suggests the whole extract does more than any fraction taken out of it — which is either interesting or a polite way of saying the mechanism is unknown. Flavonoid content also varies enormously between preparations, growing conditions and harvests, so two products labelled identically are not necessarily delivering the same thing.
Used to support the wind-down, and studied for sleep quality and self-rated stress.
People assembling an evening routine who want the traditional calming herbs rather than more melatonin. Explicitly not for anyone who is pregnant or breastfeeding, not for anyone on benzodiazepines, barbiturates, prescription sleep medicines, QT-prolonging drugs, MAOIs or other serotonergic medicines, not for anyone with a heart rhythm disorder, not for under-12s, not before driving, and not in the run-up to surgery.
Evening only. OUT roughly 30 to 60 minutes before bed, DOWN as the evening winds down. Do not take it with alcohol, and do not stack it on top of a prescribed sleeping tablet without asking your prescriber first. The first time you use it, do it on a night when you are not driving anywhere afterwards.
At 25 mg in DOWN, nothing you will notice. At 100 mg in OUT, nothing you can separate from the valerian, melatonin and lemon balm beside it. Even at the full 500 mg and upwards that has been studied, the honest magnitude is a slightly better-rated night and, in one polysomnography trial, about twenty extra minutes of sleep on average, with enough variation between people that plenty of them got none. If you feel dizzy or foggy the following morning, that is a reason to stop rather than a sign it is working.
Miyasaka and colleagues' Cochrane review (2007, CD004518) found only two randomised trials totalling 198 participants, both against active comparators rather than placebo, and concluded that trials were too few in number to permit any conclusions to be drawn. Akhondzadeh and colleagues (2001, Journal of Clinical Pharmacy and Therapeutics) randomised 36 outpatients with DSM-IV generalised anxiety disorder to 45 drops a day of Passiflora extract or oxazepam 30 mg for four weeks and found no significant difference between them, with oxazepam acting faster but causing significantly more impairment of job performance — note there was no placebo arm, so matching oxazepam in 36 people is not the same as beating nothing. Movafegh and colleagues (2008, Anesthesia and Analgesia) gave 500 mg orally to 60 ambulatory surgery patients 90 minutes before the procedure and found lower anxiety numerical rating scores than placebo (p<0.001), with sedation scores and recovery of psychomotor function comparable between groups; the authors' own conclusion was that it reduced anxiety without inducing sedation. Ngan and Conduit (2011, Phytotherapy Research) ran a double-blind crossover of passionflower tea in 41 healthy adults aged 18 to 35 for seven nights per arm and found a significantly better subjective sleep-quality rating (t(40)=2.70, p<0.01) on one of six sleep-diary measures, with no objective difference in the ten participants who underwent polysomnography. Lee and colleagues (2020, International Clinical Psychopharmacology) randomised 110 adults with DSM-5 insomnia disorder for two weeks and found total sleep time on polysomnography rose 23.05 minutes (SD 54.26) versus a 0.16 minute fall on placebo (p=0.049), with sleep efficiency and wake-after-sleep-onset improving within the group but not against placebo. Harit and colleagues (2024, Cureus) randomised 65 adults with stress and insomnia to a branded standardised Passiflora extract or placebo at bedtime for 30 days and reported significantly lower Perceived Stress Scale scores and higher total sleep time; the extract was developed commercially to improve sleep quality, and Cureus applies a lighter peer review than the other journals cited here. The EMA classes Passiflora incarnata herba as traditional use only, which means long usage rather than demonstrated efficacy. We make no claim from any of this. MASC / BODY does not offer passion flower as a treatment for insomnia or for any anxiety disorder. No trial has tested 25 mg or 100 mg of extract.
Read the labelPassion flower can cause dizziness, drowsiness, unsteadiness and impaired thinking. Do not drive or operate machinery after taking it. A published case describes a 34-year-old woman who developed severe nausea, vomiting, drowsiness, a prolonged QTc interval and episodes of non-sustained ventricular tachycardia, and needed hospital admission for cardiac monitoring and intravenous fluids — and this happened at therapeutic doses, not at an overdose. Do not exceed the label, and avoid it entirely if you have a heart rhythm disorder or take a QT-prolonging medicine. Passion flower contains beta-carboline alkaloids that inhibit monoamine oxidase in laboratory work, so do not combine it with an MAOI, and take medical advice before combining it with an SSRI, an SNRI, tramadol or any other serotonergic medicine — OUT also contains L-tryptophan, which is a serotonin precursor, so read that product's own warnings as well. It adds to the effect of benzodiazepines, barbiturates, prescription sleep medicines and alcohol. Safety in pregnancy and breastfeeding has not been established; do not use it. Stop well before any surgery and tell your anaesthetist. Not a treatment for insomnia or for any anxiety disorder.
Evidence grades describe how well an ingredient is studied — A well-supported, C emerging — not a promise of results. Educational, not medical advice. Doses are typical ranges; follow the label on the product.