Vitamin B-12 injections for weight loss: Do they work?

There is no evidence that vitamin B-12 in any form — including vitamin B-12 injections — enhances weight loss. One study published in 2005 suggested that people who took a number of different supplements, including vitamin B-12, gained weight more slowly over a 10-year period than did those who took no supplements. However, many factors have to be considered, including the fact that people who take dietary supplements tend to be more health conscious, which may contribute to better weight management.

Although vitamin B-12 is an important vitamin, it is not likely to directly impact weight loss.