Substrate ·evidence-based
interventions / St. John's Wort / mood

Does St. John's Wort help mood? (Grade B evidence)

St. John's Wort probably helps mood (Grade B, moderate certainty), especially in adults, mild-to-moderate depression. Studied doses: 300 mg ×3/day.

Exact question reviewed

Population
adults, mild-to-moderate depression
Intervention
St. John's Wort · 300 mg ×3/day
Comparator
not reported
Outcome
mood
Time horizon
not reported

Bottom line. St. John's Wort probably helps mood (Grade B, moderate certainty), especially in adults, mild-to-moderate depression. Studied doses: 300 mg ×3/day. [2 RCTs]

Direction
benefit
Magnitude
effective for mild-to-moderate depression in trials
Grade
B
Certainty
moderate
Clinical meaning
small but potentially useful
Who it applies to
adults, mild-to-moderate depression
Dose / form studied
300 mg ×3/day
Safety
contraindicated_with_ssri
The one limitation
Claim-specific limitation details are not available in this public record.

Reviewed · Evidence last changed · Claim clm_ec_sjw_mood v0

⚠ Safety in context

Grade
B
what does the grade mean?
Certainty
moderate
what does certainty mean?

Grade B / moderate: probably helps, and new studies are unlikely to reverse this — but could shrink the effect size.

Who it works for

Best-studied in adults, mild-to-moderate depression. Recorded studied dose: 300 mg ×3/day.

Evidence

StudyDesignRoleCite
St John's wort for major depressionpeer-reviewednot classifiedPMID:18843608 · DOI
A systematic review of St. John's wort for major depressive disorder.peer-reviewednot classifiedPMID:27589952

Why this grade

Reasoning trace

The current record stores Grade B at moderate certainty and links 2 publishable sources. A claim-specific domain-by-domain grading rationale is not available in this public record, so no reason for upgrading or downgrading is inferred here.

Audit and version

Claim ID
ec_sjw_mood
Claim version
not reported
Governance
legacy, not verified
Last evidence search
not reported
Last editorial review
2026-07-16T04:28:41.847Z

Public receipt · Machine-readable claim · Methodology

Dose & form

Studied intake: 300 mg ×3/day.

How it stacks up for mood

Grade history

Re-review cadence: every 12 months (Grade A/B) · next scheduled by · methodology v1.

Frequently asked

How long does St. John's Wort take to work for mood?

Trials of St. John's Wort for mood typically report effects within 2–4 weeks, though individual response varies. Studies rarely find benefit inside 1 week for chronic outcomes.

What dose was used in studies of St. John's Wort for mood?

Studied doses for St. John's Wort in mood trials cluster around 300 mg ×3/day. See the dose block for the specific range and how it varies by form.

Does St. John's Wort work for mood if I'm not deficient?

The effect concentrates in adults, mild-to-moderate depression. If your baseline is normal, expect a smaller effect than the trial averages.

St. John's Wort or the next-best alternative for mood?

See the compare block above for the head-to-head with the most-cited alternative. Grade + certainty differences matter more than any single trial.

Related

What this is — and is not

Evidence description
effective for mild-to-moderate depression in trials
Substrate's interpretation
The current reviewed record assigns Grade B at moderate certainty. A domain-by-domain rationale is shown only when recorded.
Discuss with a clinician
If you're on medication or have a condition that changes the calculus, bring the interaction & population blocks above to your pharmacist or prescriber before deciding.
Individualized medical advice
Not provided here or on any Substrate surface (API, agent tool, embed) — see YMYL policy.

Cite this page

Citation is encouraged. The proposed reuse license is CC-BY-4.0; status: pending-governance-ratification.

Plain-text citation
Substrate. Does St. John's Wort help mood? (Grade B). https://evidencebased.info/interventions/st-johns-wort/mood. Updated 2026-07-16.
BibTeX
@misc{substrate_tionsstjohnswortmood,
  author = {Substrate editorial},
  title  = {Does St. John's Wort help mood?},
  year   = {2026},
  url    = {https://evidencebased.info/interventions/st-johns-wort/mood},
  note   = {Grade B, evidencebased.info}
}

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