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In a large Danish study, a vitamin B12 level of 200 to 600 pmol/l was taken as the reference range for the general population.[1]
On this page, you can read what vitamin B12 is, what the guidelines say about a level that is too low or too high, what affects your level and which other values are best to look at alongside it.
Also known as: cobalamin. At the lab: VB12.
Vitamin B12 is a vitamin your body needs to make red blood cells. Red blood cells carry oxygen through your blood. Vitamin B12 is also important for your nervous system to work properly. You get it from animal products, such as milk, meat, fish and eggs.[2, 3]
Your body stores vitamin B12 as a reserve, mainly in the liver. A deficiency can lead to a form of anaemia, which can make you feel tired or dizzy, for example. A deficiency can also affect your nerves, for instance with tingling in your fingers. Because your body uses up its reserve first, you often only notice a deficiency after a few months or even a year.[2, 3]
The lab measures the vitamin B12 in your blood. A blood test like this can show whether you have too little vitamin B12. According to research, too little vitamin B12 is often seen in people who eat few animal products. So a low level can point to a deficiency.[2, 3]
Vitamin B12 is the only water-soluble vitamin that your body keeps in store. The store holds around 2 to 5 milligrams. This is one reason why a deficiency is rare.[2]
For a long time, the focus was mainly on clear symptoms caused by a deficiency. According to an expert review, there is now more attention for low status in groups who eat few animal products. This can be seen in a blood level. What the effects of such low status are still needs to be worked out.[3]
According to the Voedingscentrum, adults aged 18 and over need 2.8 micrograms of vitamin B12 a day. If you are pregnant, that is 3.3 micrograms. If you get a little less, that does not mean you have a deficiency straight away. For most people, the recommendation is higher than what they actually need.[2]
Labplusarts, the lab BioProfile works with, uses a reference value of 148 to 584 pmol/l for vitamin B12. The lab calls a level between these limits normal.[4]
| Value | What it can mean | Who it is for |
|---|---|---|
| 200 to 600 pmol/l[1] | The reference range for the general population, used for comparison in the study | The general population, as the reference in the study |
| 601 to 800 pmol/l[1] | Higher than the reference range; in this group, the chance of a blood clot in a vein was greater | People with a serious condition, measured before it was diagnosed |
| Above 800 pmol/l[1] | Higher than the reference range; in this group too, the chance of a blood clot in a vein was greater | People with a serious condition, measured before it was diagnosed |
Source: Arendt and colleagues, Thrombosis Research. A Danish population study of people with a serious condition, whose vitamin B12 was measured before that condition was diagnosed. These limits apply to that study.[1]
A level that is too low can point to a deficiency. According to the Voedingscentrum, a deficiency leads to a form of anaemia called macrocytic anaemia. Besides tiredness and dizziness, this can also give you heart palpitations or ringing in your ears. A deficiency can also cause memory loss, problems with your coordination and muscle weakness in your legs.[2]
According to a Danish study, a high level in the blood may point to a hidden serious condition. In that study, people with a higher level also had a greater chance of a blood clot in a vein. According to the researchers, what this means in practice still needs further research.[1]
BioProfile is working on its own zones for each value, from risk to optimal. A doctor reviews those zones before they appear in your result.
Vitamin B12 is found almost only in animal products, because bacteria in the digestive tract of animals make it. A 100 gram portion of cooked salmon contains 4.0 micrograms, and a 50 gram egg contains 0.8 micrograms. Dried seaweed and algae also contain vitamin B12, but mostly in a form that is not active and that your body does not absorb well.[2]
If you don't eat animal products, a deficiency can develop. According to an expert review, clear symptoms of a deficiency are mainly caused by a particular form of anaemia or by a strictly vegetarian diet. For vegans, the Voedingscentrum recommends products with added vitamin B12, as well as a supplement.[2, 3]
In your food, vitamin B12 is bound to a protein. Stomach acid releases it. In the small intestine, it binds to another protein from the stomach, called Intrinsic Factor. Your body needs this pairing to absorb it. Your body probably absorbs around 40 to 50% of the vitamin B12 you take in.[2]
According to the Voedingscentrum, many people do not need a vitamin B12 supplement; it brings no extra health benefit. If you would still like to take one, the advice for adults is no more than 2.8 micrograms a day from a supplement. If you take all your vitamin B12 at the same time, your body absorbs it less efficiently.[2]
Vitamin B12 is included in BioProfile 121 and 150.[5]
The BioProfile editorial team wrote this page on 2 October 2026 from the sources below, which we read on 2 October 2026. Every number on this page appears in one of those sources, with that source's number next to it. An expert has yet to check this page; once checked, the expert's name and the date of the check will appear at the top. This page offers explanation, not a diagnosis. Discuss an abnormal value with your GP.
