You correct a vitamin B12 deficiency with tablets or injections. Which form fits depends on the cause: with a dietary shortage tablets usually work well, with an absorption problem injections are sometimes needed. This article is part of our overview of vitamin deficiency. Below you read which approach fits when.
How do you correct a vitamin B12 deficiency?
The right approach depends on the cause and severity. If your shortage is from too few animal products, oral supplements usually work well. If an absorption problem is behind it, your doctor may advise injections. Always discuss the choice with your GP.
- Tablets and melt tablets - cyanocobalamin or methylcobalamin. Usually enough for mild deficiencies, also at higher doses.
- Injections - for severe deficiencies or absorption problems (such as pernicious anaemia or after stomach surgery) your doctor prescribes B12 injections.
- Diet - meat, fish, eggs and dairy. Vegans need fortified products or supplements.
Where is vitamin B12 found?
Vitamin B12 occurs almost exclusively in animal products. Plant foods naturally contain no reliable B12, which is why supplementation for vegans is a necessity, not a luxury.
- Meat and organ meat: beef, liver
- Fish and shellfish: salmon, mackerel, mussels
- Eggs and dairy: milk, cheese, yoghurt
- Fortified products: some plant drinks and meat substitutes
How long does it take to correct a deficiency?
Your blood value often recovers within 6 to 8 weeks. Nerve complaints such as tingling can take longer to recover, sometimes months, and may not fully reverse after a prolonged deficiency. That is why correcting it early matters. Read more about the symptoms and risk groups of a vitamin B12 deficiency.
Can you take too much vitamin B12?
Vitamin B12 is water-soluble, your body excretes an excess through urine. Toxicity from supplements is barely described, even at high doses. Even so, it is wise to supplement based on a confirmed deficiency rather than on a hunch. In doubt? Have your vitamin B12 value measured.
Frequently asked questions
Do tablets work as well as injections?
For a dietary shortage, yes. High oral doses are partly absorbed even without intrinsic factor. With a real absorption problem, injections give more certainty. Your doctor decides what fits.
Do I have to take B12 for life?
That depends on the cause. With veganism or a lasting absorption problem, long-term supplementation is needed. With a temporary cause it can be temporary.
Does folate affect B12?
Yes, a high intake of folate can mask a B12 deficiency. That is why they are often assessed together.
Want to measure your vitamin B12? Check your vitamin B12 value or build a custom blood test. Every blood test result at Vitalcheck includes a professional assessment by a BIG-registered doctor. A blood value is not a diagnosis: always discuss symptoms and treatment decisions with your GP.
References
- Thuisarts.nl / NHG. Vitamin B12: what if you have too little? Accessed 2026.
- Health Council of the Netherlands. Dietary reference values for vitamins and minerals. 2018.
- Netherlands Nutrition Centre. Vitamin B12. Accessed 2026.
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