B12 - some data

B12 (cobalamin) comes in 4 main forms, cyanocobalamin, methylcobalamin, adenosylcobalamin and hydroxocobalamin.

The cyano form has a bad reputation as it contains cyanide, however even at 1000 micrograms per day, it is still less than all other cyanide traces ingested through other food sources. It is the easiest to manufacture and is more stable. G&G stopped using it several years ago and switched to the methylated form.

The methylcobalamin is the methylated form, which is more bioavailable and is better when paired with adenosylcobalamin, the other biologically active form.

The hydroxo form is common for injecting B12.

Most commercial B12 manufacture is by bacterial fermentation, which is often agreed to be “natural”. Bacteria are fermented on a corn starch matrix and B12 is produced. It is possible to ferment the different types of B12 and our current B12 (methyl) is declared as fermented.

It is also possible that some producers ferment B12 (cyano) and then using a methyl transfer reaction, produce B12 (methyl).