Magnesium vs St. John's Wort for mood: which has better evidence?

A tie on evidence grade for mood (Magnesium Grade vs St. John's Wort Grade B). For mood, St. John's Wort has the stronger evidence grade.

Reviewed by Substrate editorial, Independent research collective ·

Head to head

MagnesiumSt. John's Wort
Gradestudied, no effectgrade B
Certaintymoderatemoderate
EffectNot recommended for unipolar depressioneffective for mild-to-moderate depression in trials
Studied dose300 mg ×3/day
Populationadults, mild-to-moderate depression
Safety1 modeled interaction(s)1 modeled interaction(s)
Grade
what does the grade mean?
Certainty
moderate
what does certainty mean?

Grade or certainty not assigned — evidence bucket does not yet warrant a graded claim.

Direct comparison evidence

There are no direct RCTs in our corpus comparing Magnesium and St. John's Wort head-to-head for mood. What we present above is an indirect comparison: each side's own trials, contrasted. This is standard practice for supplement comparisons — dose, population, and outcome-instrument differences between the two evidence bases add uncertainty on top of each side's own grade.

Can you take both?

No modeled interaction between Magnesium and St. John's Wort in our corpus. Absence of a recorded interaction is not proof of additive benefit — combined-effect trials are usually absent for supplement pairs, so treat "stack" claims skeptically.

Decision guidance

sources: PMID:35311615

Grade history

No grade changes yet. Initial grade assigned; re-reviewed on every 6 months (Grade C+) — next review by . Methodology v1.

Re-review cadence: every 6 months (Grade C+) · next scheduled by · methodology v1.

Frequently asked

Which has stronger evidence: Magnesium or St. John's Wort for mood?

Magnesium carries Grade — at moderate certainty; St. John's Wort carries Grade B at moderate. The stronger evidence points to a tie, subject to the caveat that direct head-to-head trials are usually absent for supplement pairings.

Can I take Magnesium and St. John's Wort together?

No modeled interaction between Magnesium and St. John's Wort; combining is not documented to be problematic, but combined-effect trials are also absent, so treat additive benefit claims skeptically.

Have Magnesium and St. John's Wort been compared head-to-head?

Direct RCTs comparing the two for mood are uncommon. This page contrasts each side's own trial evidence — that is an indirect comparison, which introduces confounds from population and dose differences. See the direct-comparison block above.

What decides between Magnesium and St. John's Wort for me?

Read the decision guidance below — the split usually comes down to population fit, interaction risk with your other medications, and how much certainty you want behind the recommendation.

Related

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Plain-text citation
Substrate. Magnesium vs St. John's Wort for mood. https://evidencebased.info/compare/magnesium-vs-st-johns-wort-for-mood. Updated 2026-07-14.
BibTeX
@misc{substrate_vsstjohnswortformood,
  author = {Substrate editorial},
  title  = {Magnesium vs St. John's Wort for mood},
  year   = {2026},
  url    = {https://evidencebased.info/compare/magnesium-vs-st-johns-wort-for-mood},
  note   = {evidencebased.info}
}