Interaction · Supplement
Vitamin B12 + Metformin: one depletes the other
Long-term metformin lowers B12 in up to a third of users — test annually.
- Overall grade
- Grade B
- Last revised
- 0
- graded outcomes
- 0
- references listed
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What is uncertain
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- Watch with Vitamin B12: About Vitamin B12
The evidence in words
The interaction
Vitamin B12 and Metformin — a depletion interaction. Long-term metformin lowers B12 in up to a third of users — test annually.
What to do
Sustained use of one lowers the other over time. Monitor status and replete the depleted nutrient if it runs low — ideally guided by testing.
About Vitamin B12
B12 is a water-soluble vitamin found almost exclusively in animal foods. It is essential for red-blood-cell formation, DNA synthesis, and the myelin sheath around nerves. Because the liver stores years' worth, deficiency develops slowly and can be missed until it causes anemia or irreversible nerve damage.
The bigger picture
Supplement–drug and supplement–supplement interactions are the reason a stack should be read as a system, not a list. This platform's interactions graph maps them; the medication side always belongs with the person who prescribes it.
Related reading
Entries that share this one's tags or conditions.
- Vitamin B12 + PPIs: one depletes the otherAcid suppression starves the absorption pathway over years.Evidence grade B
- Alpha-Lipoic Acid + Metformin: use with cautionAdditive glucose lowering — watch for lows.Evidence grade B
- American Ginseng + Metformin: use with cautionAdditive glucose lowering.Evidence grade B
- Apple Cider Vinegar + Metformin: use with cautionAdditive glucose lowering.Evidence grade B
Sources
This entry lists no references of its own — it is assembled from the entries it links to, whose sources are on their pages.
Last revised . A grade is this entry's reading of the evidence, not medical advice.