Does Probiotics help mood? (Grade C evidence)
Explore current source-reported research for this exact question. These records are separate from the synthesis below; they do not update its grade or establish a recommendation.
Probiotics shows a Grade C benefit for mood: the recorded evidence, especially in adults suggests a modest effect, low certainty. Dose range strain-dependent.
Exact question reviewed
- Population
- adults
- Intervention
- Probiotics · strain-dependent
- Comparator
- not reported
- Outcome
- mood
- Time horizon
- not reported
Bottom line. Probiotics shows a Grade C benefit for mood: the recorded evidence, especially in adults suggests a modest effect, low certainty. Dose range strain-dependent. [1 other]
- Direction
- benefit
- Magnitude
- small effects on mood/anxiety in some "psychobiotic" trials; strain-specific, heterogeneous
- Grade
- C
- Certainty
- low
- Clinical meaning
- small but potentially useful
- Who it applies to
- adults
- Dose / form studied
- strain-dependent
- Safety
- not assessed
- The one limitation
- Claim-specific limitation details are not available in this public record.
Reviewed not reported · Evidence last changed · Open evidence record (version 0)
Grade C / low: hints of benefit in small trials; a well-run RCT could easily push this to B or to null.
Who it works for
Best-studied in adults. Recorded studied dose: strain-dependent.
Evidence
| Study | Design | Role | Cite |
|---|---|---|---|
| Prebiotics and probiotics for depression and anxiety: A systematic review and meta-analysis of controlled clinical trials. | peer-reviewed | not classified | PMID:31004628 |
Why this grade
Reasoning trace
The current record stores Grade C at low certainty and links 1 publishable source. 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_b2-probiotics-mood
- Claim version
- not reported
- Governance
- legacy, not verified
- Clinician review
- Not yet reviewed by a licensed clinician
- Last evidence search
- not reported
- Last editorial review
- not verified
Dose & form
Studied intake: strain-dependent.
How it stacks up for mood
- Probiotics vs Vitamin D for mood — Vitamin D Grade C
- Probiotics vs St. John's Wort for mood — St. John's Wort Grade B
- Probiotics vs 5-HTP for mood — 5-HTP Grade C
- Probiotics vs N-Acetylcysteine for mood — N-Acetylcysteine Grade C
- Probiotics vs Saffron for mood — Saffron Grade B
- Probiotics vs Folate for mood — Folate Grade —
- All interventions graded for mood →
Grade history
- C → CSource correction by Claude (b2 garbage-source correction): replaced an off-topic search-fallback source (published before the pump's topica details →
Re-review cadence: every 6 months (Grade C+) · methodology v1.
Frequently asked
How long does Probiotics take to work for mood?
This record does not report a studied onset time for Probiotics and mood. Do not assume a typical timeframe.
What dose was used in studies of Probiotics for mood?
The recorded studied dose for Probiotics and mood is strain-dependent. This is a source detail, not a dose recommendation.
Does Probiotics work for mood if I'm not deficient?
The recorded studied population is adults. This field alone does not show whether deficiency or baseline status changes the effect.
Probiotics 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
- small effects on mood/anxiety in some "psychobiotic" trials; strain-specific, heterogeneous
- Substrate's interpretation
- The current reviewed record assigns Grade C at low 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 Probiotics help mood? (Grade C). https://evidencebased.info/interventions/probiotics/mood. Updated 2026-07-16.
BibTeX
@misc{substrate_ntionsprobioticsmood,
author = {Substrate editorial},
title = {Does Probiotics help mood?},
year = {2026},
url = {https://evidencebased.info/interventions/probiotics/mood},
note = {Grade C, evidencebased.info}
}Found something wrong on this page? Report an error →
Current source-reported research
Membership uses admitted intervention and measured-outcome associations for this exact question. Different populations, preparations, comparators and timepoints remain separate. No pooling or update to the synthesis is asserted.