Passionflower is a climbing vine with spiky tendrils and beautiful purple flowers native to Texas and Latin America. For centuries, Native Americans used it as a treatment for sleeplessness. Now it's popular around the world as a treatment for both anxiety and among the best known of the herbs as natural sleep aids, taken as a mild tea or a stronger dried, powdered extract of the herb in capsules.
How Does Passionflower Work?
Passionflower is one of the best natural sleep aids because of its action in the brain. Scientists believe that it increases levels of a chemical called GABA (gamma-aminobutyric acid) .In fact, it even contains GABA, making the same chemical that is found in the human brain . This chemical causes electrical signals in a part of the brain known as the hippocampus to calm down. It protects the brain against a group of amino acids called excitotoxins .
Glutamate (found in MSG and in most savory packaged food products) activates a drive for pleasure that can keep people awake, make them excited, or even cause madness . Glutamate lowers the threshold for pleasure, but it also lowers the threshold for pain. Aspartate (famously found in aspartame, also known as NutraSweet) "zaps" brain cells (or at least it does in laboratory mice) that regulate sleep .Cysteine (used in bakery products and as a preservative for fresh fruit) is particularly troublesome for causing insomnia in type 2 diabetics who have sleep apnea . These amino acids don't have to be labeled because they are well-known nutrients. Consumed to excess in prepared and packaged foods, however, they can "rev up" the brain so that sleep becomes difficult. Passionflower counteracts their effects.
How Well Does Passionflower Work in Treating Insomnia?
One clinical trial found no difference between passionflower and zolpidem (sold as Ambien, Edluar, and Intramezzo) in treating insomnia. Compared to no treatment at all, users of the herb as an insomnia treatment slept longer. They fell asleep faster. They woke up fewer times during the night. The study was not run long enough to confirm that passionflower has a long-term benefit, but it seems to be something you could take if your Ambien or Intramezzo weren't available. 
A team of researchers at Sungkyunkwan University in Korea and Harvard Medical School found that passionflower extracts were effective in treating anxiety and insomnia in patients who had bipolar disorder , although valerian, if the herbs are to be used singly rather than in combination, worked a little better.
In Europe, your health insurance will probably pay for passionflower extracts as a treatment for insomnia, although you're more likely to find passionflower mixed with valerian and/or than used by itself. European physicians usually consider passionflower to be a safe and reliable remedy for better sleep .
What Form of Passionflower Works Best for Promoting Sleep?
It's important to understand that passion fruit and passionflower aren't the same thing. They come from different, although related, plants. You can't drink passion fruit juice and get the same result as if you were using passionflower.
It's also important to understand that passionflower teas (whether or not they contain other herbs) and passionflower capsules don't work the same way either. The dried, powdered products are made from extracts of passionflower that concentrate the chemical components of the herb that induce sleep. The dried petals of the flower for making tea don't have as much of these ingredients, and if you heat the water to make the tea to boiling, you will lose most of them as they evaporate into the air. If you do make passionflower tea, be sure to use hot water that is not yet boiling, or the tea won't do you as much good.
There are two different ways herbal product manufacturers make concentrated extracts of passionflower. At least one
Australian company is set up to use "supercritical extraction" to get the most of the active ingredient out of the herb. This method uses carbon dioxide that is under so much pressure that it becomes a liquid. The liquid dissolves the active ingredients, and when the pressure in the processing vessel is released, the dried active chemicals are left behind. This method gets both the active chemicals and the whole herb for maximum benefit. 
Most companies soak dried passionflowers in alcohol, and then boil off the alcohol to leave the active chemicals behind. There isn't any alcohol left in the finished product. It evaporates away and is recycled. This method isn't the best way to make passionflower extracts, but the products will still work.
You'll get the best results from passionflower if your insomnia is bound up with anxiety. Of course, there's a point that if you don't get sleep, you become anxious about not sleeping. If that's you, try passionflower. It may not be the only thing you will need for chronic insomnia treatment, but if you can't get your meds, if will help you get through a few weeks until you can.