I recently learned where and how vitamin B12 is made. Moat of it is in the form of cyanocobalamin which is used to make synthetic B12. Cyanocobalamin is derived from sewage or milorganite which it is reffered to. Milorganite is also used for fertilizer. Worse, 2/3 of the stuff is manufactured in China. It is in all kinds of cereals, vitamnins, breads, etc. A more healthy option is methylcobalamin. Check it out, many sources available. It may be safe (cyanocobalamin) but it's disgusting never the less.