Hi there, is there any genetic reason or scientific reason why someone might need cyanocobalamin, while taking fairly high doses of methylocobalamin? I decided to stop the cyanocobalamin, when taking methylcobalamin. The C-B12 500mcg was an evening meal tablet, and I think by the evening I am now out of my lunchtime supply of M-B12 5000 mcg. Is this possible that the body can "run out" by the end of the day like suggested? It did originally seem like a smart move to avoid the insomnia.