Is Folsäure useful for Schlaf?

The question of whether folic acid (vitamin B9) is useful for sleep cannot be answered with strong evidence. Folic acid is crucial for cell division, blood formation, and homocysteine metabolism. Deficiency can cause fatigue, irritability, and possibly indirect sleep disturbances, but direct sleep-promoting effects are not supported by randomized controlled trials. Some observational studies suggest a link between low folate levels and poor sleep, but causal evidence is lacking. Therefore, taking folic acid specifically to improve sleep is not evidence-based. For sleep issues, established approaches like sleep hygiene, stress management, and medical evaluation should be prioritized. A blood test for folate deficiency is reasonable if deficiency is suspected (e.g., vegan diet, pregnancy, certain medications). Without deficiency, supplementation is unlikely to benefit sleep. Evidence: unclear/mechanistic. Caution: High-dose folic acid can mask vitamin B12 deficiency.