• Home
• Dietary Supplements

• Choose text size:
• A
• A
• A

June 8, 2010 | Comments: 0

Sizing Up St. John’s Wort

Many people with depression turn to St. John’s wort, an herbal supplement. Despite the promising research, there are some caveats to keep in mind.

A yellow-flowering weed, St. John’s wort has been used to treat various “nervous disorders” for centuries and is sold, usually by prescription, in Germany as an antidepressant, and in the U.S. as a dietary supplement.

St. John’s wort is one of the most researched herbal medicines. But results about St. John’s wort have often been inconsistent and hard to compare, largely because the studies have included people with different types and degrees of depression, used different herb preparations and doses, tested the herb against low doses of antidepressants, and/or did not have placebo groups.

Still, most studies have been favorable, and the consensus is that St. John’s wort works better than a placebo in treating people with mild-to-moderate depression, at least in the short term. St. John’s wort also seems to be as good as older-generation tricyclic antidepressants, and possibly newer antidepressants (SSRIs) for people with this level of depression.

Keep in mind

• The long-term safety and effectiveness of St. John’s wort is not known. Most studies have been short—less than 3 months.

• It’s not clear what the best dose of St. John’s wort is. Though 900 milligrams a day is commonly recommended, studies have used a range of preparations and doses. 

• St. John’s wort supplements vary in preparation and quality, and they may not all have the same effects as those used in studies. Some may contain little active ingredient.

• St. John’s wort is generally better tolerated than prescription antidepressants, studies show, but mild side effects include gastrointestinal upset, headaches, fatigue, dry mouth, and, rarely, increased sun sensitivity.

• St. John’s wort can interfere with a variety of drugs: statins, the blood thinner warfarin (Coumadin), certain HIV medications, digoxin (a heart drug), and oral contraceptives, among others.

• If your depression is interfering with your life, talk to your doctor or a therapist. Depression is a serious condition, and you should not self-diagnose or self-medicate with St. John’s wort. While there is continuing debate about how effective prescription antidepressants really are, these drugs are still often a first-choice treatment, especially for more severe depression.

• If you are already taking a prescription antidepressant, you should not switch to St. John’s wort on your own. And you should not combine the two, since that can increase side effects—confusion, headaches, nausea, and anxiety—especially in older people.

Read more on this topic