Vitamin B12
What it is · too little · too much · daily reference values by country
For reference only. This is not a diagnosis or a prescription. If you have concerns, talk to a doctor or pharmacist.
What it is
- Vitamin B12 is a nutrient needed for red blood cells to form and mature, for the nervous system to work normally, and for making DNA. (Korea Ministry of Health and Welfare · Korean Nutrition Society)
- Cobalamin (vitamin B12) is a water-soluble vitamin that is involved, as a coenzyme, in amino acid, nucleotide, neurotransmitter and phospholipid metabolism. (European Food Safety Authority)
Getting too little
- When vitamin B12 is lacking, cells cannot divide actively, and this is said to lead to megaloblastic anemia, nerve problems such as reduced cognitive function, digestive problems, cardiovascular disease, and more. (Korea Ministry of Health and Welfare · Korean Nutrition Society)
- Cobalamin deficiency may result in megaloblastic anaemia, which affects red blood cells and all other blood cells. (European Food Safety Authority)
Getting too much
- The evidence is not sufficient to show that eating a lot of vitamin B12 causes toxicity or side effects. (Korea Ministry of Health and Welfare · Korean Nutrition Society)
- In the upper level overview from the European Food Safety Authority, vitamin B12 is listed as having no defined adverse effects. (European Food Safety Authority)
Daily reference values by country
Korea · US · EU — tap to open
These tables are daily reference values for healthy people. Numbers in the text above are a different kind of value, and you cannot diagnose yourself from them. How to read RDA, AI and UL
Korea — 2025 Dietary Reference Intakes for Koreans (Ministry of Health and Welfare)
| Group | EAR | RNI | AI |
|---|---|---|---|
| 0–5 months | 0.3 μg | ||
| 6–11 months | 0.5 μg | ||
| 1–2 years | 0.8 μg | 0.9 μg | |
| 3–5 years | 0.9 μg | 1.1 μg | |
| Male · 6–8 years | 1.1 μg | 1.3 μg | |
| Male · 9–11 years | 1.5 μg | 1.7 μg | |
| Male · 12–14 years | 1.9 μg | 2.3 μg | |
| Male · 15–18 years | 2 μg | 2.4 μg | |
| Male · 19–29 years | 2 μg | 2.4 μg | |
| Male · 30–49 years | 2 μg | 2.4 μg | |
| Male · 50–64 years | 2 μg | 2.4 μg | |
| Male · 65–74 years | 2 μg | 2.4 μg | |
| Male · 75+ years | 2 μg | 2.4 μg | |
| Female · 6–8 years | 1.1 μg | 1.3 μg | |
| Female · 9–11 years | 1.5 μg | 1.7 μg | |
| Female · 12–14 years | 1.9 μg | 2.3 μg | |
| Female · 15–18 years | 2 μg | 2.4 μg | |
| Female · 19–29 years | 2 μg | 2.4 μg | |
| Female · 30–49 years | 2 μg | 2.4 μg | |
| Female · 50–64 years | 2 μg | 2.4 μg | |
| Female · 65–74 years | 2 μg | 2.4 μg | |
| Female · 75+ years | 2 μg | 2.4 μg | |
| Pregnancy | +0.2 μg | +0.2 μg | |
| Lactation | +0.3 μg | +0.4 μg |
US — NASEM (National Academies)
| Group | EAR | RDA | AI | UL |
|---|---|---|---|---|
| 1–3 years | 0.7 μg | 0.9 μg | — | |
| 4–8 years | 1 μg | 1.2 μg | — | |
| Male · 9–13 years | 1.5 μg | 1.8 μg | — | |
| Male · 14–18 years | 2 μg | 2.4 μg | — | |
| Male · 19–30 years | 2 μg | 2.4 μg | — | |
| Male · 31–50 years | 2 μg | 2.4 μg | — | |
| Male · 51–70 years | 2 μg | 2.4 μg | — | |
| Male · 71+ years | 2 μg | 2.4 μg | — | |
| Female · 9–13 years | 1.5 μg | 1.8 μg | — | |
| Female · 14–18 years | 2 μg | 2.4 μg | — | |
| Female · 19–30 years | 2 μg | 2.4 μg | — | |
| Female · 31–50 years | 2 μg | 2.4 μg | — | |
| Female · 51–70 years | 2 μg | 2.4 μg | — | |
| Female · 71+ years | 2 μg | 2.4 μg | — | |
| Pregnancy · 14–18 years | 2.2 μg | 2.6 μg | — | |
| Pregnancy · 19–30 years | 2.2 μg | 2.6 μg | — | |
| Pregnancy · 31–50 years | 2.2 μg | 2.6 μg | — | |
| Lactation · 14–18 years | 2.4 μg | 2.8 μg | — | |
| Lactation · 19–30 years | 2.4 μg | 2.8 μg | — | |
| Lactation · 31–50 years | 2.4 μg | 2.8 μg | — | |
| 0–6 months | 0.4 μg | — | ||
| 7–12 months | 0.5 μg | — |
EU — EFSA (European Food Safety Authority)
| Group | AI | UL |
|---|---|---|
| 7–11 months | 1.5 μg | |
| 1–3 years | 1.5 μg | |
| 4–6 years | 1.5 μg | |
| 7–10 years | 2.5 μg | |
| 11–14 years | 3.5 μg | |
| 15–17 years | 4 μg | |
| 18+ years | 4 μg | — |
| Pregnancy · 18–60 years | 4.5 μg | |
| Lactation · 18–60 years | 5 μg | |
| Pregnancy · 18+ years | — | |
| Lactation · 18+ years | — |
Sources
- EFSA DRV Finder (Dietary Reference Values) · checked 2026-10-07
- EFSA DRV Finder — nutrient descriptions · checked 2026-10-07
- EFSA Overview on Tolerable Upper Intake Levels (v11, August 2025) · checked 2026-10-07
- 2025 Dietary Reference Intakes for Koreans, Vol. 2: Vitamins (Korean Ministry of Health and Welfare · The Korean Nutrition Society; in Korean) · checked 2026-10-07
- 2025 Dietary Reference Intakes for Koreans — summary tables (Korean Ministry of Health and Welfare · The Korean Nutrition Society; in Korean) · checked 2026-10-07
- NASEM Dietary Reference Intakes summary tables (Appendix J, 2019) · checked 2026-10-07
The sentences are plain-language summaries of official sources written by SuppleBoard. Each English sentence was checked against the source text by an AI reviewer before publishing. The agencies do not endorse this site. Published 2026-10-16.