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.
B Complex side effects
Across 572 first-hand reports, people mentioned a side effect 21 times (about 4 per 100 reports). The most common: anxiety, insomnia, headache. User reports show what people notice — they can't tell you whether B Complex is safe for you.
Reported side effects
What got worse for some people
In their own words
“I've tried boosting GABA with Passion Flower, Valerian, L-Theanine, B-complex and more. No effect.”
“I tried this for 5 days and every single time I started to feeling worse again.”
“the B Complex (taken without adderall/ritalin) caused a massive ramp up in brain anxiety and physiological jitters. ... I stopped taking it.”
Is B Complex safe? What the research covers
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.
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.