What to watch with B12 and weight loss?

The provided knowledge sources do not contain specific information on the link between vitamin B12 and weight loss. In general, B12 deficiency can cause fatigue and weakness, which might indirectly hinder weight loss efforts. However, there is no strong evidence that B12 supplementation directly promotes fat loss or boosts metabolism in people with normal B12 levels. Some weight-loss clinics inject B12 as a placebo-like boost, but controlled studies show no significant effect. Caution: high-dose B12 is generally safe but unnecessary; it may cause mild side effects like acne or interactions with certain medications. A blood test (holotranscobalamin) is recommended before supplementation. The evidence for B12-driven weight loss is weak and not supported by the provided context.