Botanicals
St. John's Wort — timing, dose & interactions
Herbal antidepressant with evidence for mild-to-moderate depression — and one of the most interaction-prone supplements, weakening birth control, blood thinners, transplant drugs and more.
Also known as Hypericum perforatum
Timing
When to take it
With meals. Do not combine with prescription drugs without a pharmacist's review.
Interactions
St. John's Wort with other supplements
Safety
Medications & health conditions
St. John's wort weakens warfarin. It speeds up the breakdown of warfarin and several other anticoagulants, which can lead to clots. Do not combine without your prescriber.
St. John's wort can cause transplant rejection. It lowers blood levels of cyclosporine and tacrolimus. Never combine.
St. John's wort weakens some statins. It lowers blood levels of simvastatin and similar statins.
St. John's wort + antidepressants. Risk of serotonin syndrome, and it weakens some antidepressants such as amitriptyline and bupropion.
St. John's wort can make birth control fail. It speeds up hormone breakdown, causing breakthrough bleeding and unplanned pregnancies. Use another method or avoid it.
St. John's wort weakens several cancer drugs. It lowers levels of irinotecan, imatinib, docetaxel and others.
St. John's wort in pregnancy. Safety is not established. Talk to your clinician about treating depression during pregnancy.
Tell your anesthesiologist about St. John's wort. It interacts with many drugs used around surgery; usually stopped beforehand.
Buying guide
What to look for on the label
St. John's Wort
- Extract standardized to 0.3% hypericin — only after checking your medications
FAQ
Common questions
When is the best time to take St. John's Wort?
Breakfast or Lunch. With meals. Do not combine with prescription drugs without a pharmacist's review.
Should St. John's Wort be taken with food?
Yes. Taking it with a meal reduces stomach upset.
Can you take St. John's Wort with 5-HTP?
No — don't combine two serotonin-raising supplements. Choose one, and never combine either with antidepressants without medical advice.
Sources