Is B12 useful for Schlaf?

The question of whether vitamin B12 is useful for sleep lacks strong scientific support. B12 is crucial for nerve function and neurotransmitter synthesis, which can influence circadian rhythms and sleep regulation. Deficiency may cause fatigue or insomnia, but supplementation in non-deficient individuals has not been shown to improve sleep in high-quality trials. Evidence is limited to observational and mechanistic studies; no large randomized controlled trials confirm a benefit for sleep. Consumer tests often market B12 as a sleep aid, which overstates the evidence. A blood test to assess B12 status is advisable before supplementing. If deficiency is present, correcting it may indirectly improve sleep by resolving deficiency symptoms. Without deficiency, supplementation is unlikely to affect sleep. Safety note: B12 is generally safe even at high doses, but unnecessary supplementation is not recommended.