Evidence Level
B-Complex supplementation has a solid evidence base for stress, mood, and cognitive outcomes. Long and Benton (2013) conducted a systematic review and meta-analysis of 8 RCTs and found significant improvements in perceived stress and aspects of mood with B-complex supplementation, particularly in groups experiencing occupational stress. The VITACOG trial (Smith et al., 2010) demonstrated that high-dose B6/B12/folate supplementation slowed brain atrophy by 30% in elderly subjects with mild cognitive impairment and elevated homocysteine. Kennedy et al. (2010) showed that 90 days of high-dose B-complex improved cognitive performance and reduced mental fatigue in healthy adults. The synergistic nature of B vitamins supports supplementation as a complex rather than individual vitamins for most applications.