Nutrient depletion·Vitamin B12·Reviewed June 9, 2026
What depletes vitamin b12?
12 medications in the NutriStack database are documented to lower Vitamin B12 with ongoing use, most notably Metformin. The pattern spans 7 drug classes. Depletion builds slowly and is easy to miss; the table below shows how each medication drives it and which biomarker to check. Never start a replacement supplement without your prescriber's input.
Vitamin B12 depletion at a glance.
A quick, data-grounded summary. The per-medication table is below.
12 medications in the NutriStack database are documented to lower Vitamin B12 with ongoing use, most notably Metformin. The pattern spans 7 drug classes. Depletion builds slowly and is easy to miss; the table below shows how each medication drives it and which biomarker to check. Never start a replacement supplement without your prescriber's input.
What is documented to lower vitamin b12.
Worst documented severity first. Open any medication for its full interaction and depletion guide. Absence from this table means no documented record, not proven safety.
| Medication | Severity | How it lowers vitamin b12 | Monitor |
|---|---|---|---|
| Metformin Biguanide | Significant | Metformin impairs calcium-dependent uptake of the intrinsic factor-B12 complex in the terminal ileum, lowering B12 absorption during long-term use. | Serum B12 + methylmalonic acid |
| Esomeprazole Proton Pump Inhibitor | Moderate | Reduced gastric acid impairs release of food-bound vitamin B12 from proteins, lowering long-term absorption. | Serum B12 + methylmalonic acid |
| Lansoprazole Proton Pump Inhibitor | Moderate | Reduced gastric acid impairs release of food-bound vitamin B12 from proteins, lowering long-term absorption. | Serum B12 + methylmalonic acid |
| Omeprazole Proton Pump Inhibitor | Moderate | Reduced gastric acid impairs release of food-bound vitamin B12 from proteins, lowering long-term absorption. | Serum B12 + methylmalonic acid |
| Pantoprazole Proton Pump Inhibitor | Moderate | Reduced gastric acid impairs release of food-bound vitamin B12 from proteins, lowering long-term absorption. | Serum B12 + methylmalonic acid |
| Rabeprazole Proton pump inhibitor | Moderate | Reduced gastric acid can impair release of protein-bound vitamin B12 from food. | Serum vitamin B12 with methylmalonic acid when needed |
| Aluminum/Magnesium Hydroxide Antacid | Mild | Reduced gastric acidity can impair release of food-bound B12 and lower long-term absorption. | Serum B12 + methylmalonic acid |
| Calcium Carbonate Antacid | Mild | Chronic acid buffering can reduce release of food-bound B12 from dietary proteins. | Serum B12 + methylmalonic acid |
| Cimetidine H2 Receptor Antagonist | Mild | Chronic cimetidine therapy can reduce gastric acid and impair liberation of protein-bound vitamin B12 from food. | Serum B12 + methylmalonic acid |
| Combined Oral Contraceptive Hormonal Contraceptive | Mild | Long-term oral contraceptive use is associated with lower measured B12 status, likely from altered binding proteins and absorption dynamics. | Serum B12 + methylmalonic acid |
| Famotidine H2 Receptor Antagonist | Mild | Chronic H2 receptor blockade reduces gastric acid needed to release food-bound vitamin B12 before intrinsic factor binding. | Serum B12 + methylmalonic acid |
| Levodopa/Carbidopa Dopaminergic / Antiparkinson | Mild | Levodopa methylation increases homocysteine burden, and low B12 status can worsen this metabolic effect during chronic therapy. | Serum B12 + methylmalonic acid + homocysteine |
If you need to restore vitamin b12.
Repletion is not automatic: dose, form, and timing depend on the medication involved, and some pairings need separation from the very drug causing the depletion. Confirm with your prescriber before adding vitamin b12.
Common vitamin b12 depletion questions.
Quick answers drawn from the table above.
Which medications deplete vitamin b12?
12 medications in the NutriStack database are documented to lower vitamin b12, including Metformin, Esomeprazole, Lansoprazole, Omeprazole, and Pantoprazole. Severity differs by drug; the full table with mechanisms and monitoring biomarkers is on this page.
How do I know if my vitamin b12 is low?
The biomarkers used to track vitamin b12 status in this context include Serum B12 + methylmalonic acid, Serum vitamin B12 with methylmalonic acid when needed, and Serum B12 + methylmalonic acid + homocysteine. If you take one of the medications above long term, ask your prescriber whether checking is worthwhile; depletion develops gradually.
Should I take a vitamin b12 supplement with these medications?
Not automatically. Documented depletion makes repletion worth discussing, but the right answer depends on your labs, dose, and the specific drug. Bring it up with your prescriber or pharmacist.
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