For adults under age sixty-five, the easiest way to get B12 is to take at least one 2,000 mcg supplement each week. If you take too much, you merely get expensive pee. Well, not all that expensive: A five-year supply of vitamin B12 can cost less than twenty dollars.10 If you’d rather get into the habit of taking it daily, the once-a-day dosing is 50 mcg.11 Note that these doses are specific to cyanocobalamin, the preferred supplemental form of vitamin B12, as there is insufficient evidence to support the efficacy of the other forms, like methylcobalamin.12
