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
Can you take St John’s wort and kava together?
Tested together, early signs.
As of August 2026, St John’s wort and kava have been tested together in 1 trial, in adults with major depression and anxiety, and the one trial so far came out ahead of placebo. Scored under the same rules as everything here.
6 studies · 1 tested the actual pair · 2 cautions
What you’re seeing
- St John’s wort renders half-there: for mood, the science is still forming.
- Kava renders half-there: for stress and anxiety, the science is still forming.
- The woven cord is the rare part: one trial gave both together, and the one trial so far came out ahead of placebo.
- The red spark: 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.
You can tell before you read a word.
Magnesium + L-theanine are sold together in the same aisle. No trial has ever tested the pair. When that is true, we draw nothing between them. The nothing is the review.
The pair trial
- 2009Crossover trial · 28 people · adults with major depression and anxiety · the pair helpedsource
The other 5 studies on file tested each one alone. See all 6 studies
Fair questions
Is it safe to take St John’s wort and kava together?+
The studies on this page gave both together and reported no harm from the combination. That is not the same as a safety trial, and it says nothing about your dose or your medication.
How many studies is this based on?+
1 that gave the pair together. The papers are listed above with links to the source.
Deeper
Pairs that have been tested+
These are the combinations someone has actually run a study on. Every other pairing here is air.
Worth knowing+
- 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.
- Kava has been linked to serious liver injury, and several countries restricted or banned its sale over it. Do not take kava if you have liver problems, and do not combine it with alcohol or with medicines processed by the liver. Talk to your doctor first.