Vitamin B12
vitamins
Essential for nerve function, red blood cell production, and DNA synthesis. Deficiency common in vegans, vegetarians, and older adults.
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Benefits
Dosage
Typical Dose
500-1,000mcg daily
Upper Limit
No established upper limit (water-soluble)
Timing
Morning — may be energising
Forms & Bioavailability
Methylcobalamin
High — active form, preferred for most people
Adenosylcobalamin
High — active form used in mitochondria
Cyanocobalamin
Good — synthetic, must be converted, but well-studied
Side Effects
Interactions
Research Summary
Essential vitamin with clear deficiency symptoms (fatigue, neuropathy, anaemia). Vegans must supplement. Sublingual or high-dose oral is as effective as injections for most people.
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The Bottom Line on Vitamin B12
Vitamin B12 is well-researched with strong evidence supporting its primary benefits.It is most commonly used for energy production and nerve function and protection. As with any supplement, individual results vary. Start with the lower end of the dosage range and assess for 4-8 weeks before adjusting.
About Our Research
This profile is compiled from peer-reviewed research published on PubMed, the NIH Office of Dietary Supplements, and established nutritional science databases. Dosages reflect clinically-studied amounts from human trials where available. We update profiles as new research emerges. This is not medical advice — consult a healthcare professional before supplementing.
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Goal Guides for Vitamin B12
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