Thyroid UK
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Vitamin C and Vit B12

I have just read the following comment:

Vitamin C may destroy vitamin B12 (avoid large doses of vitamin C within one hour of taking oral vitamin B12).3,4

All B vitamins act synergistically and excess levels of one may lead to imbalance or deficiency in others. It is advisable to take B vitamins as a complex rather than as single substance supplements.

4 Replies

Oops! Been taking together😲 Got blood tests next week so will see how it has affected it,but will change my timing immediately, thanks for this info!


Don't take vitamin B complex in 4-5 days before blood test. Biotin can falsely affect the results


Thanks SlowDragon for the info, more new info for me! Learning all the time!


I can't find much evidence to support this - nearest I can find is this - quite recent article from 2014

which is actually talking about degradations when cyanocobalamin and hydroxocobalamin are suspended in fluid with acid concentrations so really about what preservatives etc might be appropriate in solutions rather than anything to do with diet. Nothing about effects on methylcobalamin

Have to admit that I haven't tried tracing back either of the references given on the page but as these are very broad references I doubt that getting back to something sensible would be easy.


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