When should I take the B12?

I usually recommend at night because it seems to improve a lot of people's sleep. That's when I do it. But others find that it increases their energy and keeps them awake. So in that situation, I recommend taking it in the morning or afternoon when you feel like you need a boost in energy. 

So it's really up to you. You might want to compare how you feel when you take it at night compared to how you feel when you take it in the morning.