Differences in B12 supplements

[katrina100]

Can anyone explain (in simple terms) the difference between Hydroxycolbalamin and Adenosylcobalamin B12 supplements. Is there a ‘better’ one to take or does it depend why you’re taking it.

[fbirder]

There are four different types of B12 available, cyanocobalamin, hydroxocobalamin, methylcobalamin and adenosylcobalamin.

Adenosylcobalamin isn't very common as a supplement as it is not as stable as the rest.

Methylcobalamin is not as stable as hydroxocobalamin or cyanocobalamin in solution.

Hydroxocobalamin is the preferred form of B12 for injection in the UK and much of the rest of Europe.

Cyanocobalamin is the preferred form of B12 for injection in the USA. Probably because it is very stable and cheaper than hydroxocobalamin.

Once they enter the cell there is no difference at all between the four different forms. They are all immediately converted to cob(II)alamin. ncbi.nlm.nih.gov/pmc/articl...

Before they enter the cell there may be differences in absorption (however they seem to be insignificant) and elimination (cyanocobalamin injections need to be more frequent than hydroxocobalamin injections as the cyanocobalamin is eliminated faster and, therefore, less of it is stored). Methylcobalamin has, anecdotally, been known to cause unpleasant side-effects.

For oral supplements it makes no real difference. I would go for the cheapest. If you try methylcobalamin then watch out for side effects (a feeling of agitation is the most often reported).

For injection I would recommend cyanocobalamin or hydroxocobalamin. Unless you have Leber's optic neuropathy (you will know if you do) when cyanocobalamin is definitely not recommended. If you're a smoker cyanocobalamin isn't recommended. You should give up smoking.

[katrina100 in reply to fbirder]

Thank you. I usually use Hydroxocobalamin but bought Adenosylcobalamin by mistake and they won't take it back. I wondered what the difference was, but it's really helpful to understand all the types, thank you for replying.

[fbirder in reply to katrina100]

Was that tablets or injections?

I've never seen hydroxocobalamin tablets and I've never seen adenosylcobalamin injections. It would be interesting to try the latter.

[helvella in reply to fbirder]

I have got some hydroxocobalamin tablets - and am currently taking them.

Not at all sure if they are any different in effect to methylcobalamin or cyanocobalamin.

Given the use of hydroxocobalamin for cyanide poisoning, I have wondered whether hydroxocobalamin might not have some ability to remove cyanide or other unwanted substances? Of course, given they are oral, we could only expect about 10 micrograms a day to be absorbed, so they might have very little impact even if the logic holds.

[katrina100 in reply to fbirder]

They're drops.