Vitamin B12 Medium Dose: 100-250 MCG

Average B12 Dosage 

Vitamin B12 Medium Dose: 100-250 MCG

The standard average vitamin B12 dose for normal people is 250 µg. When is this medium dose enough? Does a medium B12 dose cover my RDA?

Medium Dosage of Vitamin B12 – the Standard Dose for the ‘Average Person’

A daily oral dose of 150 – 250 µg is the optimal amount to ensure a healthy vitamin B12 supply for healthy people, if the supplement is expected to cover the body’s daily requirement alone. The medium dose is thus particularly well suited for vegans and vegetarians who wish to complete their nourishment with a healthy supply of vitamin B12.

Supplements with this medium dosage should ideally be taken daily, to ensure a steady B12 supply. This gentle and balanced supply corresponds much more closely to the body’s natural absorption pattern than the sudden weekly surge with a higher dose.

Note: This article refers to dosage levels for oral supplements, the dosage levels for vitamin B12 injections can be found in a separate article.

Vitamin B12 Medium Dose Profile

An oral dose of 150-250 µg of vitamin B12 is suitable for those who have:

  • otherwise good health besides lack of clarity over the exact vitamin B12 intake
  • relatively good lifestyle (moderate consumption of alcohol / tobacco, relatively healthy nutrition and diet)
  • slight stress (amateur sport, job, emotional ups and downs, therapeutic activities, irregular sleep)
  • vegetarian or vegan diet
  • pregnancy

When is a Standard Medium Dosage Insufficient?

It is sometimes necessary to take a higher dosage of vitamin B12, particularly for those who suffer from stress, illness, intake disorders, those who are taking strong medicines and those who are aware of intestinal impairments (e.g. the elderly). If you believe you fall into this category, click here to view the page on the vitamin B12 heightened dose (300 – 500 µg).

For treatment of a severe vitamin B12 deficiency with anaemia and for numerous diseases, a high dose of 100o µg or over is used. For simply covering the daily requirement, however, this is normally not necessary – even for those who suffer absorption difficulties. For more information on the high dose, simply click here: vitamin B12 high dose (1000 – 3000 µg)

Medium Dose: Ensuring the Daily Requirement is Covered

Exactly how much vitamin B12 do I need to take, in order to ensure I cover the RDA? This question is the most common amongst people who are concerned with finding the right vitamin B12 supplement for them. The answer, however, depends entirely on how effectively that person’s body is able to absorb the vitamin.

The body’s physical vitamin B12 requirement is around 1 – 2 µg, but intake should be significantly more than that, in order to keep the body’s B12 storage topped up – the DGE (Deutsche Gesellschaft für Ernährung) recommend 3 µg1, current studies suggest 7 µg2, and the Vegan Society propose 10 µg.The actual bodily intake of vitamin B12, however, is not identical to the supply taken, but rather is made up of a combination of factors. As an example, a supply of 10 µg actually only yields around 1.5 µg of utilized vitamin B12 in most cases. 

Part of the vitamin B12 supply is absorbed via a special protein, known as the intrinsic factor (IF), whilst the rest is absorbed via passive diffusion through the intestinal wall. Both means promote a healthy stomach and an intact intestinal flora.

When calculated, around 1.5 µg of vitamin B12 is absorbed through the intrinsic factor per dose, with a further 1% of the dose absorbed through passive infusion.4

So in order to achieve an actual intake of 3 µg in just one dose, the following calculation can be used: a dose of 150 µg = 1.5 µg via IF + 1.5 µg via diffusion = 3 µg

Why 150 – 250 µg of Vitamin B12?

As the formula above shows, a dose of 150 µg ensures an actual absorption of 3 µg for a single dose. Given that it is possible for both these methods of absorption to be used inefficiently by the body, a dose of 250 µg provides a generous buffer and should thus be enough for almost all people to cover their daily requirement and additionally top up the body’s B12 reserve. This medium dose can thus be seen as the optimum vitamin B12 dosage level for the majority of people.

For those suffering from stress or minor illnesses, as well as those with an unhealthy lifestyle or who are taking particular prescription medicines, a heightened dosage of 300-500 µg is recommended to cover additional bodily requirements. This dosage is also readily available in many supplements.


1Deutsche Gesellschaft für Ernährung, Österreichische Gesellschaft für Ernährung, Schweizerische Gesellschaft für Ernährungsforschung, Schweizerische Vereinigung für Ernährung (Hrsg.) „Referenzwerte für die Nährstoffzufuhr“ 1. Auflage, 5., korrigierter Nachdruck, DGE, Bonn 2013
2Mustafa Vakur Bor, Kristina M von Castel-Roberts, Gail PA Kauwell, Sally P Stabler, Robert H Allen, David R Maneval, Lynn B Bailey Ebba Nexo „Daily intake of 4 to 7 µg dietary vitamin B-12 is associated with steady concentrations of vitamin B-12–related biomarkers in a healthy young population“ Am J Clin Nutr 2010 91: 3 571-577; First published online January 13, 2010. doi:10.3945/ajcn.2009.28082
4Berlin, H., Berlin, R. and Brante, G. (1968), Oral Treatment Of Pernicious Anemia With High Doses Of Vitamin B12 Without Intrinsic Factor. Acta Medica Scandinavica, 184: 247–258. doi: 10.1111/j.0954-6820.1968.tb02452.x

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