What is the best type of vitamin B12? The scientific evidence


Vitamin B12 is a water soluble vitamin. Vitamin B12 is typically consumed in sufficient amounts in omnivorous diets. However, poor absorption due to a variety of factors combined with the increase in plant based diets has led to vitamin B12 insufficiency in large segments of the global population.


Types of vitamin B12

There are 4 main types of vitamin B1

  • 5-deoxyadenosylcobalamin
  • Cyanocobalamin
  • Hydroxycobalamin
  • Methylcobalamin


Methylcobalamin and 5-deoxyadenosylcobalamin are the metabolically active forms of vitamin B12.


However, the two others forms, hydroxycobalamin and cyanocobalamin, become biologically active after they are converted to methylcobalamin or 5-deoxyadenosylcobalamin 


Cyanocobalamin is the most used form due to its high stability, cost effectiveness and safety of use


Cyanocobalamin is a more stable and inexpensive form that appears to be best suited for oral supplementation

Obeid, R.; Fedosov, S.N.; Nexo, E. Cobalamin coenzyme forms are not likely to be superior to cyano- and hydroxyl-cobalamin in prevention or treatment of cobalamin deficiency. Mol. Nutr. Food Res. 2015, 59, 1364–1372.


'Methylcobalamin is less stable than cyanocobalamin, and it is particularly susceptible to photodecomposition' (photodecomposition means the vitamin B!2 acrtivity being decreased when exposed to light such as sunlight)


'There is no advantage to using the light-sensitive forms of cobalamin, such as methylcobalamin or 5-deoxyadenosylcobalamin, instead of the stable cyanocobalamin or hydroxycobalamin forms, which are readily converted in the body into the coenzyme forms, methyl­B12 and adenosyl­B12'

Vitamin B12 deficiency.

Green R, Allen LH, Bjørke-Monsen AL, Brito A, Guéant JL, Miller JW, Molloy AM, Nexo E, Stabler S, Toh BH, Ueland PM, Yajnik C.Nat Rev Dis Primers. 2017 Jun 29;3:17040. doi: 10.1038/nrdp.2017.40.
'Recently, it was debated whether the coenzymes methylcobalamin and 5-deoxyadenosylcobalamin can be more efficient; that is, as a ready-to-use form that does not require a prior conversion. However, the use of these more expensive formulations is not necessarily justified. In the literature, evidence of efficacy and safety is scarce'
Vitamin B12 among Vegetarians: Status, Assessment and Supplementation.
Rizzo G, et al. Nutrients. 2016. PMID: 27916823 Free PMC article. Review.
if you choose to supplement with  methylcobalamin, you may need to take a higher dose of vitamin B12 than if you supplemented with cyanocobalamin:
'However, in terms of dietary supplementation, the efficiency of methylcobalamin in tablet or liquid form is usually improved by increasing the dose size'



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