Conclusion: This meta-analysis suggests that B vitamin supplementation is associated with slowing of cognitive decline, especially in populations who received early intervention and intervention of long duration; the study also indicates that higher intake of dietary folate, but not B12 or B6, is associated with a reduced risk of incident dementia in non-dementia aged population. Given the prevalence of dementia cases in many countries with aging populations, public health policies should be introduced to ensure that subgroups of the population at risk have an adequate B vitamin status.
PubMed 34432056 ↗Vitamin B Complex
People mainly take Vitamin B Complex for energy, mood, focus. Based on 83 first-hand reports and 237 meta-analyses & systematic reviews in the medical literature. Ranked #385 of 1,974 overall.
Of reports that state an outcome, 63% are positive.
What Vitamin B Complex does, according to users
Of the people who reported each effect, the share who said it got better.
What the research says
Systematic reviews and meta-analyses from PubMed, with their published conclusions.
3+ meta-analyses or systematic reviews and 10+ randomized controlled trials in humans. The grade measures how much human research exists — read the conclusions below for what it found.
Conclusion: PN is associated with lowered plasma vitamin B12 and elevated methylmalonic acid and homocysteine. Overall, interventional studies have suggested that B-vitamins could improve symptoms of PN. Available trials have limitations and generally did not investigate vitamin status prior to treatment. Well-designed studies, especially in non-diabetes PN, are needed. This meta-analysis is registered at PROSPERO (ID: CRD42020144917).
PubMed 33619867 ↗Conclusion: Raw milk consumption was not associated with cancer (two studies) or lactose intolerance (one study). Overall, these findings should be interpreted with caution given the poor quality of reported methodology in many of the included studies.
PubMed 22054181 ↗Conclusion: The review provides evidence for the benefit of B vitamin supplementation in healthy and at-risk populations for stress, but not for depressive symptoms or anxiety. B vitamin supplementation may particularly benefit populations who are at risk due to (1) poor nutrient status or (2) poor mood status.
PubMed 31527485 ↗Dosage people report
As stated by users — not a recommendation. Follow the label or your doctor.
Reported side effects
How often each side effect came up across all reports.
What users say
Verbatim quotes, shortened only — each links to the original discussion.
“Make sure the b complex is taken away from food, coffee, or tea as b1 is blocked by those”
“restarting a vitamin B complex (couldn’t tolerate it a year ago)”
“Vitamin B complex before you start.”
“None of these have made any difference to my mood.”
“Vit. B100 complex high dose”
Top discussions (5)
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Other options for energy
User data from public discussions; research from PubMed. Information only, not medical advice — talk to a doctor before starting, stopping or combining anything. Data updated October 2, 2026. How we rate