St. John’s wort is an herb that has been used for centuries for medicinal purposes, including to treat depression. The composition of St. John’s wort and how it might work are not well understood. There is some scientific evidence that St. John’s wort is useful for treating mild to moderate depression. However, recent studies suggest that St. John’s wort is of no benefit in treating major depression of moderate severity. More research is required to help us know whether St. John’s wort has value in treating other forms of depression. St. John’s wort interacts with certain drugs, and these interactions can be dangerous. Herbal products vary greatly as to their chemical composition and quality.
It might also: Help you snooze more soundly. St. John’s wort not only contains melatonin, the hormone that regulates our sleep-wake cycles, but it also increases the body’s own melatonin, improving sleep, says a report from the Surgeon General. (These 20 ways to sleep better every night can also help.)
Maximize the benefits: For both mood and sleep problems, author Duke recommends a supplement containing at least 0.3% hypericin (the active phytochemical) per capsule or 300 mg of the extract to be taken three times daily. Warning: St. John’s wort has been shown to interact with several prescription medications, so be sure to check with your doctor before taking it.