There was a thread on here recently about the problem with taking methylcobalamin alone. The Wiki article on methylcobalamin said that one should take adenosylcobalamin as well as methylcobalamin as the latter cannot be converted to the former. Or that one should take cyanocobalamin or hydroxocobalamin as both can be converted to both of the active forms.
The Wiki article refers to a paper as the source of this non-conversion of methyl to adenosyl. However, the abstract didn't explicitly state that the conversion wasn't possible - it just made the statement that one needed both methyl and adenosyl supplements.
I got hold of a copy of the whole paper and found that it doesn't mention the methyl-adenosyl conversion. So I'm a bit doubtful about their conclusion. Actually, I'm not keen on the paper as a whole, especially as there's one obvious error (the penultimate paragraph, where it says "The suggested regimen for the oral route is about 2000 μg of CoA
daily" when talking about oral doses of B12. CoA is not B12.
Here's a link to the paper - frankhollis.com/temp/Me%20C...