What is the recommended dosage for Vitamin B12?

General: 2.4 mcg/day (RDA); Deficiency: 1,000-2,000 mcg/day; Cognitive Support: 500-1,000 mcg/day

What are the side effects of Vitamin B12?

Potential side effects include: Generally very well-tolerated, Rare: acne-like eruptions at high doses, Injection site reactions (injectable form).

Vitamin B12 (cobalamin) is an essential vitamin required for myelin sheath maintenance, DNA synthesis, and homocysteine metabolism. B12 deficiency can cause neurological symptoms including memory problems, confusion, and peripheral neuropathy. Absorption decreases with age, making supplementation important for older adults.

What dosage of Vitamin B12 has been used in cognitive studies?

Cognitive studies have used doses ranging from 500 mcg to 1,000 mcg daily, though the RDA is only 2.4 mcg. Methylcobalamin and adenosylcobalamin are the active coenzyme forms. Higher oral doses compensate for reduced absorption in older adults. Consult your healthcare provider.

What are the potential side effects of Vitamin B12?

Vitamin B12 has an excellent safety profile with no established tolerable upper intake level. Side effects are rare but may include mild diarrhea, itching, or anxiety. Injectable B12 may cause injection site reactions. Consult your healthcare provider for appropriate form and dosing.

Vitamin B12

vitamin

Also known as: Cobalamin, Methylcobalamin, Cyanocobalamin, Hydroxocobalamin

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About

Vitamin B12 is essential for methylation reactions, myelin synthesis, and homocysteine metabolism. Deficiency causes demyelination and neurological damage. A study of 202 people found supplementation improved cognition in 84% of deficient patients.

How It Works

Essential cofactor for methylation reactions and myelin synthesis; supports homocysteine metabolism; deficiency causes demyelination and irreversible neurological damage.

Evidence For Conditions

Condition	Grade	Studies	Participants
Nutritional Deficiency Cognitive Impairment	A	25	3500	View →
Age-Related Cognitive Decline	B	12	2800	View →

Side Effects

Generally very well-tolerated
Rare: acne-like eruptions at high doses
Injection site reactions (injectable form)

Drug & Supplement Interactions

Metformin (reduces B12 absorption)
Proton pump inhibitors (reduce B12 absorption)
Colchicine (reduces B12 absorption)

Always inform your healthcare provider about all supplements you take.

Related Ingredients

Folate Niacin Vitamin B6 Vitamin D Vitamin E

Quick Facts

Dosage: General: 2.4 mcg/day (RDA); Deficiency: 1,000-2,000 mcg/day; Cognitive_Support: 500-1,000 mcg/day
Forms: sublingual tablet capsule injection lozenge spray
Natural Sources: Meat, Fish, Dairy, Eggs, Fortified cereals
Upper Limit: No established UL (water-soluble, low toxicity)
Best Time: Morning, on empty stomach for better absorption (sublingual)

Evidence Summary

Nutritional Deficiency Cognitive Impairment A

Age-Related Cognitive Decline B

FDA Disclaimer: These statements have not been evaluated by the Food and Drug Administration. The products and information on this website are not intended to diagnose, treat, cure, or prevent any disease. The evidence grades presented are based on our analysis of published peer-reviewed research and do not constitute medical advice. Always consult your healthcare provider before starting any supplement regimen.