Hi Rich, So how the cycle works then is that mercury takes the methyl from the methylb12, the former methylb12 becomes remethylated in the usual scheme of things from SAM-e and methylfolate, if available, or is just disabled, and then has that methy group taken my mercury again, acting as the intermediate carrier? Or is it immediately latched onto by TCIII and escorted to the liver for recycling? In any case hydroxyb12 is converted to methylb12 to be active, just a trickle of it. A side note, there are mercury alerts even for bluegills in some Utah waters the situation has gotten so bad. I don't eat fish from Utah waters because even the ones that are not alerted have substantial mercury.