Get the B-12 sublingual tablets at Whole Foods. 2000 mcg (micrograms). They're cherry-flavored. I was taking just 1 tablet per day, but my nutritionist suggested taking 3 per day because I have some sciatica pain. I take all 3 pills at once, letting them melt under my tongue. Also better to take in the morning, because they may give you a slight burst in energy and you wouldn't want that before bedtime.
Nothing on this thread helped me but B-12. So many medications deplete B-12 and old age too. My friend told me to get this and in 7 days that sciatica was gone. You can do what you want. I have been meaning to come here for a month now because it is sad for so many to be hurting when all they have to do is buy this product. Get the one that dissolves under your tongue.