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B vitamins (vitamin B6, vitamin B12, folate) and perceived stress: grade C

Limited evidence. Direction: Benefit.

C LimitedIndustry-fundedSubjective outcome onlyShort-term only

Educational guidance, not medical advice

Why this grade

Rubric condition met: Meta-analysis positive with a lower confidence bound near zero, pooling healthy and at-risk adults, and evidence only for multi-ingredient B-complex products; two of the three supporting sources were funded by Bayer. a conservative grader would choose C over B

A meta-analysis of supplements with at least three B vitamins (often multivitamins) found a small benefit for stress (SMD 0.23, 95% CI 0.02 to 0.45) in healthy and at-risk adults; it was co-funded by Bayer HealthCare. A 33-day trial in 215 employed men, funded by Bayer Consumer Care, found better Perceived Stress Scale ratings with a product containing vitamins B6, B12 and folic acid plus vitamin C and minerals. A 3-month trial of a vitamin B complex in 60 workers found lower personal strain. The vitamin responsible cannot be separated in any of these, so the grade applies to B-complex combinations.

How we grade evidence

Studies this grade rests on

EffectMixedNo effectSize shows participants (n)201020152020Meta-analysisRCTYoung 2019, 2019: meta-analysis, n = 2,015, result not recordedKennedy 2010, 2010: RCT, n = 215, result not recordedStough 2011, 2011: RCT, n = 60, result not recorded
each study this grade rests on, by publication year and design. Solid: effect versus the comparator; half-filled: mixed; hollow: no effect; dashed: result not recorded yet. Larger marks had more participants.
Show the numbers
StudyYearDesignParticipantsResult
Kennedy 20102010RCT215result not recorded
Stough 20112011RCT60result not recorded
Young 20192019meta-analysis2015result not recorded

The effect of 90 day administration of a high dose vitamin B-complex on work stress.

Stough C, Scholey A, Lloyd J. The effect of 90 day administration of a high dose vitamin B-complex on work stress Hum Psychopharmacol, 2011. PMID 21905094

Result not recorded
Design
Randomized, double-blind, placebo-controlled trial (90 days)
Sample
n = 60
Population
Full-time workers reporting chronic work stress
Funding
Funding: not stated in the PubMed or Crossref record; full text not read.

Effects of high-dose B vitamin complex with vitamin C and minerals on subjective mood and performance in healthy males.

Kennedy DO, Veasey R, Watson A. Effects of high-dose B vitamin complex with vitamin C and minerals on subjective mood and performance in healthy males Psychopharmacology (Berl), 2010. PMID 20454891

Result not recorded
Design
Randomized, placebo-controlled, double-blind, parallel-group trial (33 days)
Sample
n = 215
Population
Healthy employed men aged 30-55
Funding
Sponsored by Bayer Consumer Care AG; one author employed by Bayer Consumer Care Ltd

A Systematic Review and Meta-Analysis of B Vitamin Supplementation on Depressive Symptoms, Anxiety, and Stress: Effects on Healthy and 'At-Risk' Individuals.

Young LM, Pipingas A, White DJ. A Systematic Review and Meta-Analysis of B Vitamin Supplementation on Depressive Symptoms, Anxiety, and Stress: Effects on Healthy and 'At-Risk' Individuals Nutrients, 2019. PMID 31527485

Result not recorded
Design
Systematic review and meta-analysis of RCTs (18 articles, 16 trials; 12 meta-analyzed)
Sample
n = 2,015
Population
Healthy and 'at-risk' adults (poor nutrient status or poor mood status)
Funding
Partially funded by Bayer HealthCare; three authors have received research funding, honoraria and conference support from the nutrition and supplement industry

Search and history

Search (): (B vitamin*[ti] OR vitamin B[ti]) AND (stress[tiab] OR mood[tiab] OR depressive[tiab]) AND (meta-analysis[pt] OR systematic review[pt])

  • Graded C (proposed): Proposed in the monograph draft
  • C to C (approved): Editor sign-off November 13, 2026: grade matches the editor-approved final page