Pooled trials put this herb level with SSRIs for mild to moderate depression, across 27 trials and 3808 patients. Two large American trials found no benefit over placebo.
Both results are real, and the difference between them is the useful part.
Quick Answer: Does St. John's Wort Work for Depression?
For mild to moderate depression, pooled trials find St. John's Wort works about as well as SSRIs over 4 to 12 weeks, with fewer side-effect dropouts. Reviews call its effect in severe depression unclear, and 2 large US trials in moderately severe major depression found no benefit over placebo. It is not a replacement for prescribed treatment.
Key Takeaways
- PubMed lists 102 trials of this herb in depression specifically.
- 27 trials with 3808 patients found response comparable to SSRIs.
- Every one of those trials lasted only 4 to 12 weeks.
- 2 large US trials in major depression found no benefit.
- Severe depression is 1 area where reviews call the evidence unclear.
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The Short Version
Before the detail, here is the evidence in 4 lines.
- Mild to moderate: A response similar to SSRIs in pooled trials.
- Tolerability: Fewer dropouts from side effects than SSRIs.
- Severe: Unclear, and not where a supplement belongs.
- Long term: Most data stop at 12 weeks, and 1 study reached 26.
For the plant itself and its safety profile, start with what the herb is and where it comes from.
What the Pooled Trials Found
Three large reviews reached broadly the same answer for mild to moderate depression.
| Review | Trials | Patients | Main finding |
|---|---|---|---|
| Cochrane, 2008 | 29 | 5,489 | Better than placebo, similar to SSRIs |
| Systematic review, 2016 | 35 | 6,993 | Better than placebo in mild and moderate |
| Meta-analysis, 2017 | 27 | 3,808 | Comparable to SSRIs, fewer dropouts |
The Cochrane review found a response rate ratio of 1.00 against SSRIs across 12 trials, and fewer dropouts from side effects.[1]St John's wort for major depression — Cochrane Database of Systematic Reviews (2008) View source It also noted that trials from German-speaking countries reported more favourable results.
The 2016 review graded the evidence moderate and flagged the lack of research in severe depression.[2]A systematic review of St. John's wort for major depressive disorder — Systematic Reviews (2016) View source
Why Two American Trials Disagreed
This is the part most summaries skip, and it is the most useful.
- 2001 trial: 200 patients at 11 centres, not effective.
- 2002 trial: 340 patients, herb against sertraline and placebo.
- What they shared: Moderately severe major depression.
- The twist: In 2002, sertraline did not beat placebo either.
In the 2002 trial neither the herb nor sertraline separated from placebo on the main outcomes. That points to a trial that struggled to detect any drug effect.[3]Effect of Hypericum perforatum (St John's wort) in major depressive disorder: a randomized controlled trial — JAMA (2002) View source
The 2001 trial concluded the herb was not effective for major depression, although remission was higher at 14.3% against 4.9%.[4]Effectiveness of St John's wort in major depression: a randomized controlled trial — JAMA (2001) View source
What It Does Not Replace
Stated plainly, because depression is treatable and the stakes are high.
- Does not replace: An antidepressant you have been prescribed.
- Never combine: With SSRIs or other serotonin-acting drugs.
- Never stop: A prescribed antidepressant to switch, without your prescriber.
- Get help today: For any thought of self-harm, call or text 988.
The combination risk is covered in the serotonin syndrome risk with antidepressants.
Where It Did Well
The favourable evidence is specific too, and the detail matters for anyone buying a capsule.
- Setting: 251 outpatients in 21 German practices.
- Product: A named extract, WS 5570, at 900 mg a day.
- Comparator: Paroxetine, an SSRI.
- Result: At least as effective, and better tolerated.
That 2005 trial in moderate to severe depression found the extract non-inferior to paroxetine over 6 weeks.[5]Acute treatment of moderate to severe depression with hypericum extract WS 5570 (St John's wort): randomised controlled double blind non-inferiority trial versus paroxetine — BMJ (2005) View source It tested 1 standardised extract, which is why the extract doses those trials used matter when you read a label.
Minor Depression and Longer Use
Two further trials temper the picture.
- Minor depression: 810 mg a day did not beat placebo over 12 weeks.
- Citalopram: Did not beat placebo in that trial either.
- 26 weeks: No difference between herb, sertraline and placebo.
- Why: Large placebo responses in both.
In minor depression, a high placebo response meant neither the herb nor citalopram separated from placebo, and both carried a notable side-effect burden.[6]The treatment of minor depression with St. John's Wort or citalopram: failure to show benefit over placebo — Journal of Psychiatric Research (2011) View source
If You Decide to Try It
For mild low mood, with no prescription medicines involved, these terms match the evidence.
- Check first: Every medicine you take, with a pharmacist.
- Expect weeks: Trials measured results at 4 to 12 weeks.
- Review: With a clinician, if nothing has changed by then.
- Know the product: Our capsule is herb, not the trial extract.
On those terms, the herb in capsule form is a starting point for a conversation with a clinician, not a prescription.
Speak to a Clinician Before Taking St. John's Wort If
- You take any prescription medicine, because this herb speeds up how the body clears many of them
- You take an antidepressant or any other medicine that acts on serotonin
- You rely on the pill or another hormonal method to prevent pregnancy
- You take warfarin, digoxin, cyclosporine, tacrolimus or any HIV medicine
- You are pregnant or breastfeeding, or have ever had a manic episode
- You have any thought of self-harm, which needs same-day help: call or text 988 in the US
Frequently Asked Questions
Why don't doctors prescribe St. John's Wort? +
Mainly because of its interactions and variable product strength. It lowers levels of many drugs, and US trials in 2001 and 2002 were negative.
What is the safest natural antidepressant? +
No supplement has been shown safer than prescribed treatment, and this herb has 862 interaction records. Safety depends on your other medicines.
Does St. John's Wort make you happier? +
In mild to moderate depression, pooled trials show a response similar to SSRIs over 4 to 12 weeks. Response means fewer symptoms, not a lift in a normal mood.
Which is better for depression, ashwagandha or St. John's Wort? +
St. John's Wort has far more depression evidence, 102 trials, and far more interactions. No head-to-head trial is in our review.
How long does it take for St. John's Wort to kick in? +
Trials measured results at 4 to 12 weeks. Judging it after a few days tells you almost nothing.
Does St. John's Wort work for severe depression? +
Reviews call it unclear. 1 German trial included moderate to severe cases, but severe depression needs a clinician, not a supplement.
Is St. John's Wort as good as an SSRI? +
In mild to moderate depression, a pooled analysis of 27 trials found comparable response and fewer dropouts. That is not a reason to switch without your prescriber.
Why did the American trials find no effect? +
Both enrolled moderately severe major depression, and in the 2002 trial sertraline also failed to beat placebo, which points to low trial sensitivity.
Can I take St. John's Wort instead of my antidepressant? +
Not on your own. Stopping or switching needs your prescriber, and the 2 must never overlap because of serotonin syndrome.
Does it work for mild depression? +
For minor depression, a 12-week trial of 810 mg a day found no benefit over placebo, and citalopram also failed.
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