What do the states mean?+
- Solid: well studied, and it works.
- Half-there: the science is still forming.
- A ghost: almost no real studies.
- Hollow: well studied, and it does not work.
- A cord: the pair itself has been tested together.
- Air: nobody has ever tested this pair.
The full scoring method: How we score
St John’s wort benefits: where the science stands
For mood: not settled yet.
Mood is what most people take St John’s wort for, and the best studies disagree: one found it helps, one found no effect. As of August 2026, the verdict on this page rests on evidence from 16 trials, drawn from the strongest research among the 214 papers on PubMed that mention St John’s wort. Every claim is checked below.
214 papers on PubMed · evidence from 16 trials · 1 caution
Claim by claim
- MoodThe science is still forming. The best studies disagree.
Pairs people ask about
The two sources we read
- 2023Meta-analysis · pools 14 trials, 2,270 people · moderate benefit for moodsource
- 2025Meta-analysis · pools 2 trials, 1,049 people · no clear effect on moodsource
Chosen as the strongest evidence out of 214 papers on PubMed. Every row links to its paper.
Fair questions
Does St John’s wort work?+
For mood, it is not settled. The best studies disagree.
Is St John’s wort safe?+
One caution is recorded: St Johns wort speeds up how the liver clears many prescription medicines. A controlled study measured a roughly 140 percent increase in CYP3A4 activity, the enzyme that processes a large share of common drugs. That can make the contraceptive pill, blood thinners, transplant medicines, HIV medicines and some antidepressants stop working properly. Do not take it alongside prescription medication without asking your doctor or pharmacist first.
Why only 2 sources, when PubMed lists 214?+
The 214 is every paper that mentions St John’s wort in any way: animal studies, blood measurements, papers where it is a side note. The strongest sources are combined reviews, and each one already gathers every trial its authors could find. Our 2 cover 16 trials between them, and every one is linked above. Both counts are measured, not estimated.