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Is the cyanocobalamin for of B-12 dangerous?
Question: Being over 50 years old, I'm looking to take a vitamin B-12 supplement. I see that many contain a form of vitamin B-12 called cyanocobalamin, yet I read on the Internet that this form is toxic. Should I be concerned?
Initial Posting: 6/10/2012    Last Update: 8/8/2017
Answer: The most common form of vitamin B-12 (cobalamin) in supplements is cyanocobalamin and although this form includes a cyanide molecule, it is very safe. Why? Even at a very high dose, it would provide about a thousand times less cyanide than is toxic, and the cyanide is excreted in the urine.
Some non-authoritative websites claim that methylcobalamin is better absorbed or more bioavailable than cyanocobalamin, but there is no clinical evidence supporting this claim. Other sites suggest that methylcobalamin supplements cannot yield one of the important, active metabolites of B-12, but this is not correct. More information about this, and another form of B-12, hydroxocobalamin, is found in the "Cobalamin (B-12)" section of the B Vitamin Supplements Review >>