I take cyanocobalamin as my B12 supplement for two reasons: its high stability and its track record of safety and efficacy.
Methylcobalamin is less stable than cyanocobalamin and is particularly susceptible to photodecomposition—that is, destruction from light exposure. One study found that even up to 2,000 micrograms a day of methylcobalamin wasn’t enough to correct vitamin B12 deficiency in one of three vegans tested.
There may be one caveat, though. Methylcobalamin may be better for those with impaired kidney function. It’s also been speculated that oral methylcobalamin or injected hydroxycobalamin may be preferable in smokers, but that hasn’t been conﬁrmed. If you do have decreased kidney function and your doctor recommends methylcobalamin, you may need a much higher dose because it’s less stable, so be sure to ask them about what’s best given your condition.
This video goes into more detail on the best type of vitamin B12 supplementation:
To learn more about vitamin B12, visit our topic page, which covers a broad range of the latest evidence-based research.