Yes Vitamin B12 does help speed up your metabolism and also boosts your metabolism which gives you energy.
The intake of Vitamin B12 not only speeds up and boosts your metabolism but also b12 helps support a healthy nervous system as well.
B12 can help you lose weight as well as give you energy so you won't want to eat anything else.
When you have enough B12 and a good fast metabolism and eat less food that contains a lot of calories then you can lose weight.
Exercise and eating healthy is also needed to lose weight fast and at a healthy pace.
You can lose safely around 80 lbs to 100 lbs of weight in a year.