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VitaminStrong Evidence

Vitamin B12

Cobalamin

Essential for nervous system function, DNA synthesis, and red blood cell formation. Deficiency is common in vegans, vegetarians, older adults, and those on metformin.

Known Health Benefits

Nervous system health and myelin formation
Red blood cell formation
DNA synthesis
Energy metabolism support

Active Compounds

Methylcobalamin, cyanocobalamin, adenosylcobalamin, hydroxocobalamin

Dosage Guidance

500–1000 mcg daily (sublingual methylcobalamin preferred for deficiency)

Always consult a healthcare provider for personalized dosing.

Potential Side Effects

Generally very safe at normal doses; rare skin reactions with injections

Known Drug Interactions

Metformin, PPIs, and H2 blockers significantly reduce absorption over time

Evidence Classification

Strong Evidence

Supported by randomized controlled trials (RCTs), systematic reviews, or meta-analyses published in peer-reviewed journals.

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This entry is for educational purposes only. It is not medical advice. Always consult a qualified healthcare provider before starting, stopping, or changing any supplement regimen, especially if you take medications or have health conditions.