St. John's wort

Originally Published: August 28, 1998 - Last Updated / Reviewed On: December 12, 2014
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Dear Alice,

What is the most recent information on the beneficial effects of St. John's wort and possible side effects? What is the recommended dose?

M

Dear M,

What’s the word on St. John’s wort? Also known by its botanical name, Hypericum perforatum, this supplement is derived from a yellow flowering plant. It has been used — with mixed results — as an herbal remedy for a wide range of ailments, including mild to moderate depression, menopausal symptoms, somatization disorder (when mental experiences are converted into physical symptoms in the body), and wound healing. Research suggests that St. John's wort raises levels of serotonin, norepinephrine, and dopamine (different neurotransmitters that help boost morale and mood), but the active ingredient that produces this effect is still unknown. More research is needed to better understand how St. John’s wort works and what beneficial effects it may have on health. You also asked about the recommended dosage for this supplement. How much of the supplement to take and the number of times you'll need to take it daily will vary depending upon the condition you wish to treat.

Although the evidence is mixed, there are a number of studies that suggest St. John’s wort can be effective in treating depression without the side effects common to traditional anti-depressant medications (It’s good to note that it’s not recommended for the treatment of severe depression). Unlike prescription anti-depressants, which can cause side effects such as lowered sex drive and delayed ejaculation and/or orgasm, the same sexual side effects have not been associated with the use of St. John's wort. However, this does not mean that the supplement is free from potential adverse side effects, some of which include:

  • Fatigue
  • Dry mouth
  • Dizziness
  • Vivid dreams
  • Headache
  • Skin rash
  • Gastrointestinal discomfort, such as diarrhea
  • Allergic reactions
  • Irritability
  • Restlessness
  • Increased sensitivity to sunlight
  • Confusion
  • Anxiety

Due to the lack of scientific evidence, it’s hard to know how taking St. John’s wort may affect different individuals. You may want to be especially wary of taking this supplement if you’re:

  • Taking prescription medications. Anti-depressant medications, monoamine oxidase inhibitors (MAOIs), and HIV/AIDS medications combined with St. John’s wort can lead to possibly dangerous interactions. Additionally, St. John’s wort can affect how the body metabolizes medicine, which may make certain medications less effective. If you’re using any other medications, prescription or otherwise, it’s best to let your health care provider know before taking this herbal supplement.
  • Pregnant or breastfeeding. Limited research has been done on women who are pregnant or breastfeeding. Until more is known, women who are pregnant or breastfeeding are advised not to take St. John's wort.
  • Have certain health conditions. Components of St. John's wort may raise blood pressure, possibly resulting in a stroke. Those who are already at risk of high blood pressure should be especially cautious.

As a rule, it’s helpful to remember that "natural" does not necessarily mean safe. Since St. John's wort is an herbal supplement and not regulated by the U.S. Food and Drug Administration (FDA), the quality of the supplement may vary. For more even more detailed information, check out the National Center for Complementary and Alternative Medicine website. Before trying St. John's wort, or any other natural supplement, it’s recommended that you talk with your health care provider. Doing so may help you gather all of the necessary information to decide wort the best course of action is for you.

Alice

For more information or to make an appointment, check out these recommended resources:

Medical Services (Morningside)

Student Health Service (CUMC)