Vitamin B12: normal range and what it means
Essential for nerves and red blood cells; low levels cause fatigue.
Normal range
Adult reference range.
- Low< 300 pg/mL
- Normal300 – 900 pg/mL
- High≥ 900 pg/mL
What it measures
A vitamin vital for nerve function, DNA and red blood cells. Common deficiency in vegans and older adults.
What moves it
Animal-food intake, gut absorption, certain medications.
How to bring it into range
Animal foods or B12 supplements; address absorption issues.
How fast it responds
Weeks.
Also reported as: cobalamin · b12 · vitamin b-12
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Common questions
- What is a normal Vitamin B12 level?
- Normal: 300 – 900 pg/mL. Adult reference range.
- What does a high Vitamin B12 mean?
- A value above the reference band means Vitamin B12 is outside the range typical for a healthy adult. A single reading is rarely conclusive on its own — what matters is the trend across draws and the other markers around it, which is why HealthOS reads the whole panel together rather than one number at a time.
- How do I improve my Vitamin B12?
- Animal foods or B12 supplements; address absorption issues.
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Reference ranges are general-population guidance compiled from common clinical laboratories, not a diagnosis. Lab-to-lab ranges differ. Always read your results with your doctor.