St. John's Wort vs Vitamin D for mood: which has better evidence?
St. John's Wort has the stronger evidence for mood (St. John's Wort Grade B vs Vitamin D Grade C). For mood, St. John's Wort has the stronger evidence grade.
Head to head
| St. John's Wort | Vitamin D | |
|---|---|---|
| Grade | grade B | grade C |
| Certainty | moderate | low |
| Effect | effective for mild-to-moderate depression in trials | small mood benefit, mostly in people who are deficient |
| Studied dose | 300 mg ×3/day | — |
| Population | adults, mild-to-moderate depression | — |
| Safety | 1 modeled interaction(s) | 1 modeled interaction(s) |
Grade B / moderate: probably helps, and new studies are unlikely to reverse this — but could shrink the effect size.
Direct comparison evidence
There are no direct RCTs in our corpus comparing St. John's Wort and Vitamin D 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 St. John's Wort and Vitamin D 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
- If certainty matters most — choose whichever side carries the higher certainty rating at a similar grade.
- If you're on medications — check each side's interaction pages before deciding; safety differences dominate small evidence-grade gaps.
- If your population is under-studied — the smaller-effect side with better population evidence often wins over the higher-grade side studied in a different demographic.
- If cost matters — form and dose page differences (St. John's Wort vs Vitamin D) can invert the practical winner.
Grade history
No grade changes yet. Initial grade assigned; re-reviewed on every 12 months (Grade A/B) — next review by . Methodology v1.
Re-review cadence: every 12 months (Grade A/B) · next scheduled by · methodology v1.
Frequently asked
Which has stronger evidence: St. John's Wort or Vitamin D for mood?
St. John's Wort carries Grade B at moderate certainty; Vitamin D carries Grade C at low. The stronger evidence points to St. John's Wort, subject to the caveat that direct head-to-head trials are usually absent for supplement pairings.
Can I take St. John's Wort and Vitamin D together?
No modeled interaction between St. John's Wort and Vitamin D; combining is not documented to be problematic, but combined-effect trials are also absent, so treat additive benefit claims skeptically.
Have St. John's Wort and Vitamin D 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 St. John's Wort and Vitamin D 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
Cite this page
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Plain-text citation
Substrate. St. John's Wort vs Vitamin D for mood. https://evidencebased.info/compare/st-johns-wort-vs-vitamin-d-for-mood. Updated 2026-07-14.
BibTeX
@misc{substrate_ortvsvitamindformood,
author = {Substrate editorial},
title = {St. John's Wort vs Vitamin D for mood},
year = {2026},
url = {https://evidencebased.info/compare/st-johns-wort-vs-vitamin-d-for-mood},
note = {evidencebased.info}
}