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Nutrition Supplements

Vitamin B12 — Which Form is Best for You?

By April 5, 2016January 23rd, 2024No Comments

Adenosylcobalamin, Hydroxycobalamin, Methylcobalamin, Cyanocobalamin!

Ever had your vitamin B12 level checked and been instructed by your doctor to take a vitamin B12 supplement?

If you’re like most people (and physicians), you probably think that all vitamin B12 is the same. This is not true! There are many forms…if you need to increase your Vitamin B12 intake, do you know which form is best for you?


Synthetic or Natural

Most nutrition supplements (as well as B12 shots and fortified foods) contain the synthetic form of Vitamin B12 – cyanocobalamin. Yep, you guessed it, it contains cyanide, which is a toxic substance. On top of ridding itself of cyanide, your body has to be able to convert the molecule to a biologically active form of vitamin B12 (first to methylcobalamin and then to hydroxycobalamin or adenosylcobalamin) in order to be able to use it.

Just as our individual genetics differ (and the efficiency of our biochemical pathways), so do our individual requirements for vitamin B12.

  • A person with a MTR genetic SNP (single nucleotide polymorphisms) has an increased potential for needing more vitamin B12.
  • A person with a MTRR genetic SNP has an increased potential for having less efficiency in regenerating vitamin B12 in the methylation pathway (and thus may have a higher vitamin B12 requirement).
  • A person with a COMT genetic SNP may do best with the hydroxycobalamin or adenosylcobalamin forms of cobalamin.

Common Medications Increase B12 Requirements

Other things factor into our individual vitamin B12 needs — like certain medications. You’d be amazed at how many commonly prescribed medications deplete vitamin B12 or reduce our ability to absorb it!

These are just some medications that increase intake requirements of vitamin B12.

  • metformin (type 2 diabetes)
  • antacids, H2 blockers, proton pump inhibitors (GERD and GI reflux)
  • cholesterol-binding bile acid sequestrants (high cholesterol)
  • anti-seizure drugs (anti-convulsants)
  • colchicine (gout)
  • several oral antibiotics (examples: cephalosporins, sulfa drugs, penicillin family, quinolones, tetracycline derivatives)
  • oral contraceptives, menopause meds (estrogens)
  • methotrexate (chemotherapy)
  • corticosteroids (inhalers for asthma)

Assessing vitamin B12 Deficiency/Insufficiency

A holistic approach to assessing nutritional status of vitamin B12 begins with signs, symptoms, and diet.

Blood tests are key to determining whether or not someone might benefit from vitamin B12 supplementation; this reveals how much vitamin B12 is in the blood, though not how much is getting into the body’s cells. Measuring methylmalonic acid and homocysteine provides information about whether the body’s cells have access to enough vitamin B12.

There are a few ways to help understand why Vitamin B12 levels are low — the presence of anti-parietal/anti-intrinsic factor antibodies in the blood, B12 related genetic SNPs, and medications that increase Vitamin B12 requirements.