Can I discontinue my Vitamin B12 (B12) supplement?

Can You Discontinue Your Vitamin B12 Supplement?

No, you should not discontinue your B12 supplement without first determining the underlying cause of your deficiency and whether that cause has been corrected. 1

Critical Decision Point: Identify the Cause

The ability to discontinue B12 supplementation depends entirely on whether the underlying cause is reversible or permanent:

Permanent Causes Requiring Lifelong Treatment

If you have any of the following conditions, you will require lifelong B12 supplementation and should never discontinue it 1, 2:

• Pernicious anemia (autoimmune destruction of intrinsic factor) - requires monthly injections for life 1, 2
• Bariatric surgery (gastric bypass, sleeve gastrectomy, biliopancreatic diversion) - requires 1 mg daily oral OR 1000 mcg monthly IM indefinitely 1
• Ileal resection (>20 cm of distal ileum removed) - requires 1000 μg monthly injections for life 1
• Total or partial gastrectomy - requires lifelong supplementation 2
• Inflammatory bowel disease with significant ileal involvement (>30-60 cm) - typically requires lifelong treatment 1

Potentially Reversible Causes

You may be able to discontinue supplementation if your deficiency was caused by 1, 3, 2:

• Medication-induced deficiency (metformin >4 months, proton pump inhibitors >12 months, H2 blockers, colchicine) - if the medication is discontinued 3
• Dietary insufficiency (strict vegan/vegetarian diet) - if you resume eating animal products 2, 4
• Temporary malabsorption (small bowel bacterial overgrowth, fish tapeworm, tropical sprue) - if the underlying condition is successfully treated 2

Essential Testing Before Discontinuation

Do not discontinue supplementation without first undergoing diagnostic testing to identify the cause 3, 5:

• Intrinsic factor antibodies - if positive, confirms pernicious anemia requiring lifelong treatment 3
• Helicobacter pylori testing - to evaluate for atrophic gastritis 5
• Autoimmune gastritis evaluation - checking for autoantibodies 5
• Medication review - identify drugs that impair B12 absorption 3

Critical Monitoring After Apparent Correction

Even if your B12 levels have normalized, this does not mean you can safely discontinue treatment 1:

• Patients with malabsorption will redevelop deficiency once supplementation stops 1
• B12 stores can last 2-3 years, so deficiency may not recur immediately but will eventually return 3
• Neurological damage from recurrent deficiency can become permanent and irreversible if deficiency is allowed to progress for >3 months 2

Maintenance Protocol If Discontinuation Is Considered

If testing confirms a reversible cause and you attempt discontinuation 1, 5:

• Monitor B12 levels every 3 months initially, then annually once stable 1
• Check methylmalonic acid (MMA) if B12 levels are borderline (180-350 pg/mL), as serum B12 may not reflect functional status 5
• Target homocysteine <10 μmol/L for optimal outcomes 1
• Resume treatment immediately if levels drop below 180 pg/mL or if neurological symptoms develop 5

Dangerous Pitfalls to Avoid

• Never take folic acid without adequate B12 levels - this can mask B12 deficiency while allowing irreversible neurological damage (subacute combined degeneration of the spinal cord) to progress 1, 6, 2
• Do not rely solely on serum B12 levels - up to 50% of patients with "normal" serum B12 have metabolic deficiency when measured by MMA 3
• Do not ignore neurological symptoms (paresthesias, gait disturbances, cognitive changes, memory problems) - these can become permanent if treatment is delayed 1, 5, 7

Special Population Considerations

• Adults >75 years should continue supplementation due to high prevalence of metabolic B12 deficiency (18-25%) 3
• Pregnant or lactating women have increased B12 requirements (4 mcg daily) and should not discontinue 2
• Patients with cardiovascular disease or stroke history should maintain treatment to keep homocysteine <10 μmol/L 1

Bottom line: Unless you have confirmed that your B12 deficiency was caused by a temporary, reversible condition that has been corrected, you should continue supplementation indefinitely. 1, 4 Failure to do so risks return of anemia and development of incapacitating, irreversible neurological damage. 2