it may not help with weight loss in itself, the deficiancy may not make you gain weight, but if you are deficient you may feel tierd and sluggish and try to eat sugary food to gain energy and 'perk yourself up' - you may gain weight when this happens, the subsequent taking of B12 pills may make you feel better in yourself and in less need of sugary foods etc - as a result you may find it easier to lose weight, you may also feel like being more active. If you are not deficient, taking the vitamin pills will not make you feel better and are probably going to cause more harm than good, B vits are not like Vit C, you overdose much quicker and your body cannot expel as efficeintly as with Vit C - be careful.