Vitamin B12 Increased Dose: 300-500 MCG

Extra B12 

Vitamin B12 Increased Dose: 300-500 MCG

An extra increased dose of vitamin B12: Covering the RDA for the elderly and people with absorption difficulties, diseases or stress.

Heightened Dose of Vitamin B12 – Cover the Daily Requirement with an Increased Dose

A daily oral dose of 300 – 500 µg can cover the body’s daily requirement, in cases where it has been increased – for example, through malabsorption, stomach problems, intestinal problems or for the elderly.Since absorption problems are unfortunately quite common nowadays as a result of general poor intestinal health, high levels of stress and unhealthy lifestyles, this extra dose has become the dose of choice in many cases.

Increased Dosage Profile

A heightened dosage of 300 – 500 µg is the right choice for those who are:

  • elderly
  • suspicious of suboptimal absorption
  • breastfeeding
  • previous sufferers of a vitamin B12 deficiency
  • regularly taking medicine 
  • under physical, emotional or mental stress
  • undertaking a spiritual transformation and/or personal upheaval
  • subject to rigorous sporting activity
  • going through a disease or recovery period
  • experiencing a high workload (physical and mental)
  • following an unhealthy lifestyle (e.g. smokers, heavy drinkers)

The Complex Absorption Method for Vitamin B12

The body’s daily vitamin B12 requirement for an adult is given by the Deutsche Gesellschaft für Ernährung (DGE) as 3 µg.If an oral supplement is designed to cover this daily requirement, however, the dosage has to be considerably higher than this figure, which can be explained by the absorption mechanism of vitamin B12. Vitamin B12 can be absorbed the following two ways3:

  1. Via the transport protein known as the intrinsic factor (up to 1.5 µg per dose)
  2. Through passive diffusion in the intestinal wall (roughly 1% of the dose)

When vitamin B12 is obtained from the diet, it can typically be taken in many doses throughout the day, allowing the route of intrinsic factor to be utilized to optimum effect each time. However, when oral supplements are chosen to cover the entire daily requirement, it’s important to calculate the amount of B12 that will be utilized by the body first, in order to ensure that the RDA is being met.

Assuming that the body’s absorption is optimal, a single dose of 150 µg will cover the entire daily requirement:

1.5 µg + 150µg /100 = 1.5 + 1.5 = 3 µg

Vitamin B12 Nutrition and a Heightened Requirement

Unfortunately, the body’s B12 intake is impaired for lots of people, as a result of an insufficient intrinsic factor, stomach problems or intestinal issues. Additionally, many living situations also require a heightened supply of vitamin B12 (see the list above). In these cases, a dose of 300-500 µg becomes necessary, in order to ensure this need is met. 300 µg per dose is also enough for passive diffusion alone to meet the daily requirement – meaning it is very useful for people who lack a healthy intrinsic factor.

Since it is possible for both means of absorption to work inefficiently, many supplements today simply contain 500 µg. This dosage contains a good buffer to care for various absorption difficulties and is also sufficient to cover the daily requirement for many who suffer from known intake disorders too.

When is the Heightened Dose Insufficient?

A dose of 1000-3000 µg is used for those suffering a severe B12 deficiency with anaemia, as well as in the treatment of certain illnesses. More information on this can be found in our article vitamin B12 high dose.

The Extra Vitamin B12 for an Increased Need

A vitamin B12 dose of 300-500 µg offers the necessary extra B12 to cover an increased need. Readers who find the above profile for this heightened dose matches their lifestyle are in good hands with this dosage. Higher dosages than this are only really designed for specific therapeutic treatment, meaning that this heightened dosage provides full coverage for most people.


1Park, S. and Johnson, M. A. (2006), What is an Adequate Dose of Oral Vitamin B12 in Older People with Poor Vitamin B12 Status?. Nutrition Reviews, 64: 373–378. doi: 10.1111/j.1753-4887.2006.tb00222.x
2Deutsche 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
3Berlin, 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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