Serum B12
Oral B12 Supplements

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Types of Oral B12 Supplements

There are two different chemical forms of vitamin B12 used in oral supplements:

  • Cyanocobalamin
  • Methylcobalamin

If you choose to use oral vitamin B12 treatment, you will need to decide which of these is best for you. In some locations, only one of these types might available because of government regulation or market forces, so you will have no decision to make.

Although I use the cyanocobalamin for my investigations, this was commenced at a time when methylcobalamin was not available in Australia. If I was starting now, with the methyl form available, I would possibly have used it instead.


Cyanocobalamin has the following advantages:

  • Most readily available in some locations, including Australia
  • Low cost
  • Most stable form of cobalamin

Cyanocobalamin has the following disadvantages:

  • Not the natural form of cobalamin
  • Requires conversion, within the body, to the biologically active methyl form
  • Conversion to the methyl form produces small quantities of cyanide; the potential for toxicity is uncertain, although experts have not advised against the use of the cyano form


Methylcobalamin has the following advantages:

  • It is the natural form of cobalamin
  • Does not require conversion, within the body, to the methyl form
  • Does not produce cyanide within the body

Methylcobalamin has the following disadvantages:

  • Until very recently, not readily readily available in some locations, including UK and Australia
  • Higher cost?
  • Less stable form of cobalamin, although apparently not a significant problem as it is now commercially available

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Normal vs Sublingual Oral B12

There are two methods of supplying oral B12 supplements:

  • Pill or capsule
  • Sublingual lozenge

Pills and capsules

Most commercially available oral vitamin B12 is the cyanocobalamin in a pill; this is the form that I have used for most of my research on myself. In Australia, this form is readily available in doses ranging from 50µg to 1000µg. Smaller doses, typically about 10µg, are often included as part of multivitamin pills or capsules.

The pill or capsule is swallowed normally, with all absorption taking place in the digestive tract.

Sublingual lozenge

Methylcobalamin is available as a flavoured sublingual lozenge. They are intended to be dissolved under the tongue, allowing the vitamin B12 to be absorbed directly into the bloodstream. I have not investigated the effectiveness of this treatment.

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Advantages and Disadvantages of Oral B12 Treatment

Advantages of oral B12 treatment

  • Painless
  • No prescription required
  • Self-administered
  • No risk of needle stick injury to medical staff
  • Low cost
  • Reduced risk of adverse reactions
  • Reduced risk of fatal hypokalaemia

Disadvantages of oral B12 treatment

  • Slow to build up body stores
  • Ineffective in cases where there is no passive absorption
  • Requires total patient compliance
  • No formal record of treatment

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Why I Have Used Oral B12 Treatment

My original decision to use oral vitamin B12 was based on the expert opinion of several authors, the most useful articles being references FA01, and FA03 on the References page .

I rejected the more traditional treatment, using injected vitamin B12, for the following reasons:

  • According to recent research, in particular by Kuzminski et al, reference FA01, oral B12 should be as effective as injected B12.

  • I would need to have a prescription from a GP for the B12, and someone to inject it.

Following the initial treatment, I continued to use oral B12, for the following additional reasons:

  • The data sheet for the injected B12 strongly recommends against such treatment until there is a definite diagnosis.

  • Because of my heart arrhythmia, and the warning of risk of hypokalaemia in the data sheet, injections would need to be done in a medical centre with access to a cardiologist.

NEO-CYTAMEN Data Sheet, reference FB02:

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Suggested Doses of Oral B12 Supplements

If possible, please discuss any treatment with your doctor first. There are some conditions, possibly including intestinal bacterial overgrowth, in which oral vitamin B12 supplements have been reported to be ineffective.

The correct dose of oral vitamin B12 supplements will depend on what you need to do:

  • Build up vitamin B12 Stores
  • Maintenance

To find out more about oral vitamin B12 doses, I suggest that you read references FA01, FA02 and FA04; there are links to these articles on the References page.

Build up vitamin B12 Stores

If you have been diagnosed with vitamin B12 deficiency, and choose to rebuild depleted stores using oral vitamin B12 supplements, you need to take very large doses for at least the first few months.

Even a person with pernicious anaemia is usually able to absorb about 1% of any oral vitamin B12 dose. If you take a dose of 1000µg, you should absorb about 10 µg by passive diffusion. This is four times the recommended daily intake, and allows sufficient excess for storage.

A healthy person can only absorb a maximum of about 10 µg from any one dose, regardless of the size of the dose. The total body store in a healthy person is approximately 2-3mg.

For most people, a dose of 1000 µ will therefore provide an effective 10 µg intake; this is sufficient to rebuild the body stores after about 200 doses.

If you take two doses of 1000 µg each, for 100 days, your stores should be filled at the end of that time.

It is absolutely essential that you monitor your B12 stores during this time, by measuring serum B12, to ensure that you are absorbing the oral vitamin B12.


The size of the maintenance dose depends on the cause of the deficiency.

A healthy vegan only requires a very small maintenance dose of at least the recommended daily intake. This is available in multivitamin capsules, where typically about 10-50 µg of cyanocobalamin is included.

For any other person who has a vitamin B12 deficiency, unless you are certain that you have only a mild malabsorption, it is best to err on the side of safety. A single daily dose of 1000 µg should provide an effective intake of 10 µg, more than adequate in most cases

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Suggested Method of Taking Oral B12 Supplements

For best absorption of the vitamin B12 supplement, try to take them about half an hour before breakfast or evening meal.

I have used three different doses of cyanocobalamin pills, and treat each one differently:

Nature's Own 1000µg

Do not chew, or swallow whole. Allow the slimy, but tasteless, outer coating to dissolve in the mouth. Wait until the pill breaks up into a fine grit, then swallow the grit with water.

Nature's Own 250 µg

Do not chew, or swallow whole. This version is different to the 1000µg tablet. It does not have a slimy outer coating, and does not break up into a grit. This tablet has a mild, slightly sweet, pleasant flavour and can be sucked until it completely dissolves in the mouth.

Blackmores 100µg

Do not suck or chew this one; it has a very unpleasant taste. It dissolves very quickly, so I suggest swallowing whole with water.

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