Is B12 useful for sleep?

The question of whether vitamin B12 improves sleep lacks strong scientific evidence. B12 is essential for red blood cell formation, DNA synthesis, and nervous system function. A deficiency can cause fatigue and neurological issues that may indirectly affect sleep. However, no high-quality clinical trials demonstrate a direct sleep-enhancing effect of B12 in healthy individuals with normal levels. Some small studies suggest a link between B12 and melatonin regulation, but the evidence is weak and inconsistent. For people with diagnosed B12 deficiency, supplementation can improve overall health, which might benefit sleep. Without a proven deficiency, taking B12 specifically for sleep is not evidence-based. Be cautious of exaggerated marketing claims. The recommended daily intake is about 4 µg for adults; higher doses are generally unnecessary.