How much B12 is safe?

Although at high doses, vitamin B-12 is still reasonably safe, the amount of vitamin B-12 that is the recommended dietary allowance or RDA varies for each age group, says WebMD. Infants up to six months should have 0.4 micrograms a day, and babies from seven- to 12-months need 0.5 micrograms.

Toddlers from one- to three-years old should have 0.9 micrograms of vitamin B-12, while children from four to eight need 1.2 micrograms and children from nine to 13 need 1.8 micrograms. All individuals who are 14 years and older need 2.4 micrograms. Vitamin B-12 amounts can be reached with food or supplements, explains WebMD.