St. John's Wort Supplements: Benefits, Dosage and Safety
St. John's wort supplements have evidence for mild to moderate depression, but they interact with a long list of medicines, including antidepressants, birth control pills, blood thinners, HIV drugs and transplant medicines. Never start it without talking to a doctor or pharmacist.
Evidence at a glance
| Use | Grade | What the research shows |
|---|---|---|
| Mild to moderate depression | B | Better than placebo in many trials. |
A: strong, consistent human evidence · B: moderate · C: limited or mixed · D: good evidence of no benefit.
St. John's wort is a yellow-flowered herb used for centuries for mood.
How to take it
Only under medical guidance. See supplements for mental health.
Safety and interactions
Can cause serotonin syndrome with antidepressants, make birth control fail, and reduce the effect of many drugs. Also increases sun sensitivity.
Always tell your doctor and pharmacist about the supplements you take. Check combinations with our interaction checker.
Sources
This page is for education and is not a substitute for advice from your doctor. Read our medical disclaimer.