There has been a ton of talk about B12 around here lately, which has brought up a question I've always wondered. The synthetic form of B12 that is readily available is commonly cyanocobalamin, which metabolizes to two other forms of cobalamin (I don't recall which these are), and results in a byproduct of cyanide. How is this cyanide excreted? Also, what are the portions of cyanide produced, and can this be harmful to the body?