Supplement × Prescription·Evidence index
PubMed indexes 8 records that name Metformin and Vitamin B12 together, either in the title or in an interaction, co-administration, or pharmacokinetic context. The key findings come first, in the authors’ own words, followed by every study with its design and PubMed link.
A summary of published research, not medical advice. A pharmacist can check any combination against your full list of medicines and supplements.
Reviews and human studies first. Each quote is the authors’ own conclusion about their study, not a NutriStack assessment, and a single study is not a consensus.
“The reduction of vitamin B12 may be induced by metformin in a dose dependent manner.”
“In diabetics with cognitive disorders who are on biguanide therapy, it is necessary to determine the level of vitamin B12 in the serum in order to rule out possible pseudo-dementia and to avoid possible hematological and neurological disorders. Unfortunately, vitamin B12 deficiency remains frequently unrecognized in those patients.”
“Long-term use of metformin in DPPOS was associated with biochemical B12 deficiency and anemia. Routine testing of vitamin B12 levels in metformin-treated patients should be considered.”
Strongest relevance first: papers naming both substances in the title, then human trials and systematic reviews.
“The reduction of vitamin B12 may be induced by metformin in a dose dependent manner.”
Names both Metformin and Vitamin B12 in its title.
“In diabetics with cognitive disorders who are on biguanide therapy, it is necessary to determine the level of vitamin B12 in the serum in order to rule out possible pseudo-dementia and to avoid possible hematological and neurological disorders. Unfortunately, vitamin B12 deficiency remains frequently unrecognized in those patients.”
Names both Metformin and Vitamin B12 in its title.
“Long-term use of metformin in DPPOS was associated with biochemical B12 deficiency and anemia. Routine testing of vitamin B12 levels in metformin-treated patients should be considered.”
Names both Metformin and Vitamin B12 in its title.
“We report two cases who had symptomatic vitamin B12 deficiency related to metformin use; the mechanisms are discussed. The clinician must be aware of the possibility of metformin-associated B12 deficiency in users who suffer cognitive impairment, peripheral neuropathy, subacute combined degeneration of the cord or anaemia.”
Names both Metformin and Vitamin B12 in its title.
“Vitamin B12 deficiency should be treated in all affected patients, and supplementation should be considered in those with borderline levels when confirmatory diagnostic tests for deficiency are unavailable. Clinical guidelines should place greater emphasis on the recommendations for measuring and supplementing vitamin B12 in these patients.”
Names both Metformin and Vitamin B12 in its title.
Names both Metformin and Vitamin B12 in its title.
“Long term metformin leading to Vitamin B12 deficiency is common knowledge, however we need more targeted guidelines on when to screen and treat for B12 deficiency. Some subsets of the population such as elderly and vegetarians are more prone and hence we need to educate more physicians and patients on the same.”
Names both Metformin and Vitamin B12 in its title.
“This review emphasizes the importance of early detection and supplementation to prevent adverse outcomes. By analyzing the current evidence, the review aims to inform healthcare professionals about best practices for managing vitamin B12 deficiency in patients on metformin, offering insights to guide future clinical practices and research directions.”
Names both Metformin and Vitamin B12 in its title.
Search-based evidence indexes have real limits, and it is worth being explicit about them:
NutriStack is a free iPhone app for organising a supplement routine: what you take, when, and what the published record says about it. Its exploratory interaction checker covers Metformin, Vitamin B12, and several hundred other substances.
Log your routine, get reminders at the times you choose, and scan a label to add a product. The checker is a research and organisation tool, not a clinical decision aid.
NutriStack is an informational and organizational tool, not a medical service, and not a substitute for professional advice. Always consult a qualified healthcare professional before starting, stopping, or changing any supplement or medication.
