Conclusion: The findings of this systematic review suggest that supplementation of B Complex vitamins, especially folic acid, may have a positive effect on delaying and preventing the risk of cognitive decline. Ascorbic acid and a high dose of vitamin E, when given separately, also showed positive effects on cognitive performance, but there is not sufficient evidence to support their use. The results of vitamin D supplementation trials are not conclusive in assessing the potential benefits that vitamin D might have on cognition.
PubMed 35268010 ↗B-Complex Vitamins
People mainly take B-Complex Vitamins for anxiety, energy. Based on 7 first-hand reports and 5 meta-analyses & systematic reviews in the medical literature. Ranked #1451 of 1,974 overall.
Of reports that state an outcome, 0% are positive.
What B-Complex Vitamins 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.
At least one meta-analysis, or 5+ randomized controlled trials. The grade measures how much human research exists — read the conclusions below for what it found.
Conclusion: There is no high quality evidence to support the effectiveness of nutritional supplements and herbal medicine for women with PCOS and evidence of safety is lacking. High quality trials of nutritional supplements and herbal medicines examining menstrual regulation and adverse effects in women with PCOS are needed.
PubMed 29178904 ↗Conclusion: In this review, the evidence that single clinically defined cardiovascular risk factors are significantly associated with incident AD is inconsistent at best. The strength of the association of cardiovascular risk factors and AD can be influenced greatly by changing the parameters of measurement of risk factors and by identifying interactions between the factors.
PubMed 18703981 ↗Conclusion: This review doesn't support a benefit from folic acid supplementation on cognitive function in the elderly. Whereas low folate serum levels may be related to increased risk of cognitive impairment and high levels associated with low levels of vitamin B12 can contribute a further deterioration, it is suggested as precautory measure to re-examine the present level of food fortification with folic acid to maximize benefits and limit potential risks.
PubMed 22566307 ↗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.
“Magnesium & the B-vitamins calm me down instantly.”
“I have read about kudzu root and B-complex vitamins (the family member drinks mostly beer)”
“Nicotinamide/Nicotinic Acid/Niacin (B3) creates NAD^+ which is essential for the production of BH4, a cofactor for Dopamine synthesis.”
“Soon, even B-complex vitamins stopped working. Not just magnesium, but all B vitamins (B6, B1, and others) became ineffective.”
“way back I tried some B-complex vitamins and L-theanine which helped but not that much.”
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Other options for anxiety
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