Myths vs facts: B12 and Müdigkeit

The question about myths vs facts regarding B12 and fatigue is important because many believe that B12 supplements or injections universally boost energy. Fact: B12 deficiency can indeed cause fatigue, weakness, and neurological issues, especially in vegans, older adults, or those with gastrointestinal disorders. However, B12 deficiency is relatively rare in the general population. The myth that B12 injections provide energy even without a deficiency is not supported by evidence; studies show no benefit in individuals with normal levels. Moreover, excessive intake (e.g., high-dose supplements) may rarely cause side effects. The provided context lacks specific information on B12 and fatigue, so this answer relies on general medical knowledge. For personalized advice, blood tests (holotranscobalamin, methylmalonic acid) are necessary.