Which Vitamin B12 supplement is the best?

Eating a plant-based vegan diet is one of the healthiest diets when considering the plethora of vitamins and minerals that you get at every meal whilst eating a rainbow of fruit and vegetables.

But there is one vitamin that will elude the healthy vegan, and can lead to series and potential risk of deficiency if not supplemented.

I am talking about Vitamin B12.

So, dutifully, one goes to the chemist or online to source this supplement and is then faced with a confusing decision. Which Vitamin B12 supplement is best?






Above are some of the Vitamin B12 supplements available. Not only do you have to make a choice between the 4 different types – Cyano-cobalamin, Hydroxy-Cobalamin, Adenosyl-cobalamin and Methyl-cobalamin but there are also other jargon terms too! What the bloody hell is the difference between activated, bioactive and sublingual you have probably asked yourself at one stage.

The last thing I want is for your journey of Veganism to be confusing and hard so let me set some facts straight for you!

First, I am going to give the punch line away at the very start – All forms of Vitamin B12 have been shown to improve Vitamin B12 levels.

Which, as a Vegan, is what you want!

But keep reading and you will discover the nuances between each of the 4 forms and why some are marketed as being apparently superior to another.

To begin, there are 4 different forms of Vitamin B12 available:

  • Methyl-cobalamin
  • Adenosyl-cobalamin
  • Hydroxyl-cobalamin
  • Cyano-cobalamin

Conceptually, Methyl-cobalamin, Adenosyl-cobalamin, and Hydroxyl-Cobalamin are preferable because they are identical to the forms that naturally exist in humans and animal foods. Cyano-cobalamin is the synthetic form of Vitamin B12 and is man-made. It occurs in small amounts in human tissue as a result of cyanide intake from industrial exposure (very rare), foods and chemicals containing cyanide and smoking.

Also, once again, conceptually, (being a key word), Methyl-cobalamin and Adenosyl-cobalamin are marketed on supplements as the active or bioactive forms because these are the two forms that are involved in important metabolic processes within the human body.

But, and this is a huge but…

Numerous studies have shown that all forms of Vitamin B12 ingested do not retain their original forms.

What does this mean?

Simply, it means that it doesn’t matter what form of Vitamin B12 you choose to use because the body will take the only part it wants from the supplement, whether it be Methyl-cobalamin, Adenosyl-cobalamin, Hydroxyl-cobalamin or Cyano-cobalamin.

The supplement Vitamin B12 will go through what’s called intracellular metabolism (activity inside a cell), where the body splits off the front molecule and takes the useful Cobalamin molecule and create its own active Vitamin B12.

This process will occur regardless of the original form of Vitamin B12 ingested.

This is because the conversion involved to create Vitamin B12 active forms do not use the original Methyl-or Adenosyl- group.

Which means there is no benefit whatsoever in buying these particular Vitamin B12 supplements.

This image shows what is happening in your body.


b12 motabalism


intracellular metabolism

So now we know:

  • Cyano-cobalamin is a man-made synthetic form of Vitamin B12 and exists in human tissue in trace amounts, whereas Methyl-cobalamin, Adenosyl-Cobalamin and Hydroxy-cobalamin occur naturally in human tissue and animal foods.
  • The difference between active and inactive Vitamin B12.
    1. To recap, Vitamin B12 is only considered Active when the body has created its own Methyl-cobalamin and Adenosyl-Cobalamin within the cell.
    2. Which means, Inactive Vitamin B12 is any of the 4 forms ingested in a Vitamin B12 supplement (no matter what the label claims) before the body goes through its own processes to activate it within the cells.
  • All forms of Vitamin B12 supplement will improve your Vitamin B12 levels.


Therefore, there is no advantage to which Vitamin B12 supplement you choose to take other than a consideration of cost.

Now that that issue is settled, just a word of caution.

There have been some concerns over cyanocobalamin as a treatment for Vitamin B12 deficiency due to possible toxicity of cyanide accumulation over long term use. So far, I have only found it a concern if one is also smoking a packet (20+) of cigarettes a day. I am digging deeper into this, and the post will be coming soon.

There are of course other questions regarding Vitamin B12 (it’s a large study area of over 50 years!) such as oral, sublingual or injections, why is it such a big deal, the efficacy of food products supplementing Vitamin B12 and the body’s ability to synthesis its own Vitamin B12.

I hope this covers all the possible questions of Vitamin B12 and if there are any more questions I am more than happy to create another post on it so let me know!

To your health, and always remember, what you eat will change the world!




Carmel R. (2008). Efficacy and safety of fortification and supplementation with Vitamin B12: Biochemical and physiological effects. Food Nutrition Bulletin, 29(2), 177-187. http://journals.sagepub.com/doi/abs/10.1177/15648265080292S121

Chalmers, J. N., & Shinton N. K. (1965) Comparison of hydroxocobalamin and cyanocobalamin in treatment of pernicious anemia. Lancet, 2(7426), 1305-1308. https://ac.elscdn.com/S0140673665923366/1-s2.0-S0140673665923366-main.pdf?_tid=38c81674-175a-11e8a56b-00000aab0f01&acdnat=1519253870_191180db2a3752c0787b3e3012d78bcd

Gräsbeck R. (2013). Hooked to Vitamin B12 since 1995: A historical perspective. Biochimie, 95(5), 970-975. http://dx.doi.org/10.1016/j.biochi.2012.12.007

Gräsbeck, R., & Tanner S. M. (2011). Juvenile selective Vitamin B12 Malabsorption: 50 years after its description – 10 years of genetic testing. International Pediatric Research Foundation, Inc., 70(3), 222-228. doi:10.1203/PDR.0b013e3182242124

Malouf, R., & Sastre, A. A. (2003). Vitamin B12 for cognition. Cochrane Database of Systematic Reviews, 3, 1-24. doi:10.1002/14651858.CD004394.

Paul, C., & Brady, D. M. (2017). Comparative Bioavailability and Utilization of Particular Forms of B12 Supplements with Potential to Mitigate B12-related Genetic Polymorphisms. Integrative Medicine: A Clinician’s Journal, 19(1), 42-49. http://eds.b.ebscohost.com.ezproxy.newcastle.edu.au/eds/detail/detail?vid=0&sid=71efe8cd-d06f-4a1fae3f4b710cc62d3a%40sessionmgr104&bdata=JnNpdGU9ZWRzLWxpdmU%3d#AN=123816638&db=ccm





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