Vitamin B12 Dosage

There are several different forms of vitamin B₁₂. Dosage is based on which form you are taking, why you are taking it, and what other medical conditions you have. For general supplementation purposes, vitamin B₁₂ dosing guidelines are based on Recommended Dietary Allowances (RDAs). The dosages for oral and nasal forms of the vitamin are much higher than for the injectable form.

Vitamin B12 Information

An Introduction to Vitamin B12 Dosages

The recommended dose of vitamin B₁₂ depends on several different factors, such as:

Which form of vitamin B₁₂ you take
The reason you take the vitamin
Other medical conditions you may have.

As always, do not adjust your dosage without your healthcare provider's approval.

Types of Vitamin B12

There are several different forms of vitamin B₁₂. Injectable vitamin B₁₂ and vitamin B₁₂ nasal spray (CaloMist™, Nascobal^®) are prescription-only medications that have been proven safe and effective. Tablets, sublingual ("under the tongue") tablets, capsules, and liquids are alternative forms that are available as non-prescription dietary supplements. Lastly, a vitamin B12 patch is available, but there is little evidence to suggest that this vitamin can be absorbed through the skin.

The dosages for the oral and nasal forms are much higher than for the injectable form, since only a small percentage of the dose for oral or nasal forms actually reaches the bloodstream. It is not clear how much of the vitamin (if any) is absorbed from vitamin B₁₂ patches.

Vitamin B12 Dosing Guidelines for General Supplementation

For general supplementation purposes, the Recommended Dietary Allowances (RDAs) for vitamin B₁₂ are as follows:

Age	RDA
0 to 6 months*	0.4 mcg daily
7 to 12 months*	0.5 mcg daily
1 to 3 years	0.9mcg daily
4 to 8 years	1.2 mcg daily
9 to 13 years	1.8 mcg daily
14 years and older	2.4 mcg daily
Pregnant women	2.6 mcg daily
Breastfeeding women	2.8 mcg daily

*RDAs are not established for vitamin B₁₂ for infants under one year old; instead, an "Adequate Intake" level is provided.

For nutrients that can cause toxicity, a "Tolerable Upper Intake Level" (UL) is given. This is the maximum that can be taken from all sources, including the diet, without causing significant toxicity. There are no UL values for vitamin B₁₂, since the risk of toxicity is quite low.

It is recommended that people over 50 years old should get most of their vitamin B₁₂ requirements through supplements, such as a multivitamin, or fortified foods to which vitamin B₁₂ has been added. Older people have difficulty absorbing vitamin B₁₂ naturally found in food, but not the vitamin B₁₂ in supplements or fortified foods.

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