Including food sources and any supplements, an adequate intake of vitamin B12 is considered 2.4 micrograms (mcg) a day for people ... taking no more than 350 mg per day in supplements, though ...

The amount of vitamin B12 in an egg depends on its size and a large egg contains about 0.6 mcg of vitamin B12 in it. The recommended daily intake for most adults is 2.4 mcg, meaning one large egg ...