vitamin/energy/cognition
Vitamin B12
Water-soluble vitamin essential for red blood cell formation and nervous system function. Crucial for vegans.

Vitamin B12
Water-soluble vitamin essential for red blood cell formation and nervous system function. Crucial for vegans.
88
A
evidencesafe
Warning
Do not take without Folate (Vitamin B9) — B12 and Folate work together in DNA synthesis and the methylation cycle.
Proven Benefits
01Prevents megaloblastic anemia and fatigue
02Essential for DNA synthesis and nerve myelin sheaths
03Aids in energy metabolism
04Supports mood regulation and cognitive function
05Lowers homocysteine levels (heart health)
Chemical Forms
Recommended
- Methylcobalamin
- Adenosylcobalamin
Avoid
- Cyanocobalamin (Synthetic form)
Expert Note
Cyanocobalamin is cheap but bound to a cyanide molecule that the body must detach and process. Methylcobalamin is the active form ready to be used by the brain, especially important for people with the MTHFR gene mutation.
Protocol
Amount
500-1000 mcg
Frequency
Daily or Weekly (depending on dose)
When
Morning, preferably on an empty stomach for sublingual formats
Condition-Based Dosing
Vegan/Vegetarian Maintenance
250 mcg daily OR 2000 mcg weekly
Clinical Deficiency
1000 mcg daily or injections
Older Adults (>50 yrs)
500 mcg daily
Safety & Limits
Upper Safe Limit
No established upper limit (Water-soluble, excess is excreted in urine)
Cycling
Safe for continuous use
Contraindications
Leber's optic atrophy
Cobalt allergy
Synergies
Folate (Vitamin B9)
RequiredB12 and Folate work together in DNA synthesis and the methylation cycle.
Avoid Combining With
- ✕Metformin (Diabetes drug) depletes B12 levels.
- ✕PPIs (Omeprazole, antacids) block the stomach acid needed to absorb B12 from food.
Updated 3/27/2024