Maybe you’re tired but can’t wind down or you suffer from anxiety. So you’re up scrolling your phone and stumble across passionflower as a potential remedy. Here it is, your “cure.”
Not so fast.
As with many herbal supplements found online and at your local nutrition shop, passionflower deserves a critical look. Many of us would prefer to take something natural than something cooked up in a lab. But natural doesn’t always mean safe or effective. Like any other medication or health product, results may vary and you owe it to yourself to do some research.
Passionflower, also known as granadilla, maypop, passion vine and the Latin name Passiflora incarnata, is one of hundreds of varieties of Passiflora. It is a wildflower originally used by indigenous Americans, including the Aztecs, as a sedative.
In modern times, passionflower is found in nutritional supplements that claim to soothe anxiety, insomnia, and restlessness among other things. You can find it in liquid extracts, capsules, tablets and even tea.
Like many herbal supplements — even those with long histories — scientific research on passionflower is limited.
Look around online and you’re likely to see passionflower products associated with numerous benefits, but not all of those benefits are backed by solid research. Science has only scratched the surface with passionflower research, and more is needed.
That said, there is evidence that passionflower may help with symptoms of anxiety, sleeplessness, and potentially ADHD. There are many things that can fall under the umbrella of “anxiety symptoms”. In Europe, it’s approved for the treatment of “nervous unrest,” tension, and restlessness, to name a few. It may also be useful in treating nausea related to anxiety. Ever been so nervous you felt sick to your stomach? — yeah, that nausea.
Are there additional health benefits to taking passionflower? Perhaps. But these are the ones with scientific backing:
A handful of studies seem to connect passionflower and lessened anxiety symptoms.
One of the more widely cited studies compared the effects of passionflower extract with the effects of oxazepam, an anti-anxiety medication. The study was randomized and double-blind, a gold standard for scientific research, though there were relatively few participants. Thirty-six patients diagnosed with generalized anxiety disorder were given either passionflower or oxazepam for four weeks. According to the researchers, “no significant difference was observed” between the two treatments — both were effective in treating anxiety. Further, compared with oxazepam, the participants using passionflower experienced fewer side effects related to job performance.
Another well-designed but small study compared the effects of passionflower with that of a placebo in the treatment of pre-surgical anxiety. (If you’ve ever been through surgery, you know feeling anxious beforehand is standard). Thirty participants received passionflower and the other 30 received a placebo. Both groups filled out a questionnaire several times before surgery. Overall, those in the passionflower group reported less anxiety than the other participants. Another similar study found passionflower to reduce anxiety in dental patients.
While other studies on passionflower and anxiety have shown positive results in mice, human studies generally carry more weight.
If passionflower can reduce feelings of anxiety, it isn’t a leap to think it may help people sleep. After all, if you’ve ever been caught in a bout of insomnia, you know how closely sleeplessness and anxiety are related. However, while passionflower has historically been used as a sedative, there isn’t much in the way of sound scientific research supporting this. It’s important to note: a lack of overwhelming scientific evidence doesn’t necessarily mean passionflower isn’t effective in this area, merely that it hasn’t been proven to be.
One study in humans looked at the sedative qualities of passionflower in tea. The researchers measured six sleep-related qualities and determined passionflower tea “yields short-term subjective sleep benefits for healthy adults with mild fluctuations in sleep quality.”
While there doesn't seem to be any studies that directly investigate passionflower and potential blood pressure changes, one that focused on anxiety symptoms did measure potential blood pressure effects. Those researchers determined there was not a significant difference in blood pressure when comparing participants who took passionflower versus those who took a traditional anti-anxiety medication prior to having a tooth removed. However, they did not compare the differences in blood pressure to people not receiving any anti-anxiety treatment.
One small study looked at the use of passionflower in the treatment of attention-deficit hyperactivity disorder (ADHD) and found the plant’s extracts could be a “novel” treatment for ADHD. The researchers compared ADHD-diagnosed children on passionflower to those taking a traditional medication and noted no difference between the two. However, the researchers themselves admit, “our results require confirmation in a larger study.”
One of the drawbacks of not having long-term scientific studies available is we simply don’t know the long-term risks (or possible rewards) of passionflower. That said, it’s not known to be harmful.
Still, it can make you drowsy, so you may want to steer clear of heavy machinery or important commitments until you know how it will affect you. Also, you may not want to share it with your pregnant friend — it can induce contractions.
In rare cases, large doses may result in irregular heart rhythms, according to the Memorial Sloan Kettering Cancer Center. So don’t take more than you need to or more than a supplement label suggests.