Thyroid UK

What dose of B12 should I be taking?

I'm hypothyroid and taking 125 microgram levothyroxine daily. I definitely have gut issues- reflux, cannot eat meat or bread etc and have started supplementing with a "Super B complex plus folic acid" capsule that contains all the B vitamins. The quantity of B12 is 50micrograms daily. Can anybody advise whether this is a sufficient dose?

5 Replies

You can take 1,000mcg of methylcobalamin. Solgar or Jarrows are the two brands I know who make this type.

Ideally you want to ensure you are taking methylcobalamin for vitamin B12 supplementation and methylfolate for folate supplementation. If your vitamin B complex contains other forms of vitamin B12 and folate you may want to change to one that contains these two as they are better absorbed.


maggiesloper You need a sublingual B12, as Bluebug has suggested either Solgar or Jarrows. The B12 in your B Complex, as a tablet or capsule, is going to be destroyed by stomach acid. By taking a sublingual lozenge you dissolve it under the tongue and it gets directly into the bloodstream so bypassing the stomach.

Depending on your B12 level, tested before supplementing, you need either 5000mcg or 1000mcg. 5000mcg would be for boosting a very low level.



What are your B12 and folate blood results and ranges?


Whatever B12 you take it has to be methylcobalamin and not cyanocobalamin. Sublingual is best as it dissolves in our mouth. If you have stomach problems, taking either a good Apple Cider Vinegar mixed with water or juice (a few teaspoons or more if you prefer). Or Betaine with pepsin tablets before or during meals. We have low acid as we are hypo and most probably have low acid which then causes problems as food isn't able to be digested.

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The usual cause of a B12 deficiency is not dietary but an absorption problem. If you have an absorption problem then the amount in the supplement you have is not going to have any impact and you would need to be taking doses of around 1000mcg a day ... and even then that may not work.

People respond very differently to different forms of b12 - for some methyl gets the best results - for others it doesn't - there are a lot of genetic and other factors involved which just aren't fully understood - whilst methyl is the form that is used for some processes, adenosyl is used for other processes - most people don't have a problem converting methyl to adenosyl but some can.

Ideally you should get the absorption problem recognised by your GP and get proper treatment - shots - though getting the treatment that suits you can be very difficult - please take a look at the PAS forum on health unlocked - there is lots of advice on B12 testing etc in the pinned posts and lots of discussion in the other posts


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