Vitamin guide
Vitamin B12
Vitamin B12 supports red blood cell formation, nervous-system function, and DNA synthesis. It is especially relevant for vegans, older adults, people with absorption issues, and some medication users.
Strong for deficiencyRed blood cell formationNervous-system functionDNA synthesis
Supports
- Red blood cell formation
- Nervous-system function
- DNA synthesis
- Energy metabolism when deficiency is present
Best for
- Vegan and vegetarian diets
- Older adults
- People on long-term metformin or acid-reducing medicines
- Fatigue workups where B12 status is relevant
Cautions
- Neurological symptoms should not be self-managed.
- Testing may include B12 plus methylmalonic acid or homocysteine when unclear.
- Treating deficiency may require clinician-guided dosing.
Food Sources
Fish
Meat
Poultry
Eggs
Dairy
Fortified foods
Nutritional yeast if fortified
Supplement Forms
Cyanocobalamin
Methylcobalamin
Hydroxocobalamin
Adenosylcobalamin
Timing
Can be taken with or without food; morning is common in daily multivitamin routines.
Interactions To Check
Metformin
Proton pump inhibitors
H2 blockers
Nitrous oxide exposure
FAQs
Can B12 give energy?
B12 can improve energy when deficiency is contributing to fatigue. It does not act like caffeine when B12 status is already adequate.
Do vegans need B12?
Yes, vegan diets typically need reliable B12 from fortified foods or supplements because natural food sources are mainly animal-derived.