Vitamin B12 (Methylcobalamin)
B vitamins & energyFunction & benefits
Vitamin B12 contributes to the normal function of the nervous system, normal psychological function, normal red blood cell formation, energy-yielding metabolism and the reduction of tiredness and fatigue (EFSA-authorised claims); vegans, older adults and people on long-term metformin or acid-reducing drugs need it most.
Dosage & how to use
| Recommended dose | 500–1000 µg daily (the NRV is 2.5 µg; higher doses make up for poor absorption) |
| Best time to take | In the morning with breakfast |
| Frequency | Once daily |
Best forms to choose
Methylcobalamin or adenosylcobalamin, or the stable cyanocobalamin; sublingual tablets are available.
Important warnings
A very safe water-soluble vitamin; EFSA has set no upper limit
Persistent numbness in the hands or feet calls for a B12 blood test with your doctor
Vegans need a regular source of B12
Drug interactions
Metformin, proton pump inhibitors (such as omeprazole) and H2 blockers lower B12 absorption with long-term use; take high-dose vitamin C two hours apart.
Related supplements
- Pantothenic Acid (Vitamin B5)B vitamins & energy
- Riboflavin (Vitamin B2)B vitamins & energy
- Thiamine (Vitamin B1) & BenfotiamineB vitamins & energy
- Niacin (Vitamin B3) — NicotinamideB vitamins & energy
Scientific references
- EFSA Journal 2009;7(9):1223 (vitamin B12 health claims)
- EFSA Journal 2010;8(10):1756 (vitamin B12, neurological and psychological functions and tiredness)
- Stabler SP, Allen RH. Annu Rev Nutr 2004 — PMID: 15189123
Content last updated: 17 October 2026 · Based on published sources and research (EFSA / NIH / PubMed)
⚖️ Medical disclaimer: The information and data provided here are for health education and nutritional guidance only. They are not a medical diagnosis and never replace a direct consultation with your doctor or pharmacist. Always consult your doctor before starting any supplement, especially during pregnancy or breastfeeding or when taking long-term medication.