there shouldn't really be any difference between methyl and cyano. There is a lot of hype about methyl being more natural because it is one of the two forms used in the cells but the process by which B12 moves from blood to cells actually involves stripping the methyl/cyano element off and then it gets recombined in the cell if it is needed by the cell.Methyl is less stable and more expensive.
the only contra-indication for cyano is a rare genetic condition called lebers syndrome which means a particular sensitivity to the cyanide component ... and smoking would be a no-no because of the sensitivity.
I am assuming that you aren't based in the UK because the protocols generally discussed here are those used in the UK. In the US there is no standard protocol, particularly around loading shots. The UK also uses hydroxocobolamin and has longer period for standard maintenance doses as a result.
You could try pointing your doctor at the BCSH standards re loading doses
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