Vitamin B12

Cyanocobalamin

Prepared by the ezGLP team. Sources last checked September 5, 2026.

Also known as Vitamin B12, B12 injection

Routes represented in the knowledgebase: Subcutaneous (SubQ) / Oral / Sublingual.

Educational overview

FDA-approved prescription injection for vitamin B12 deficiency; intramuscular and subcutaneous products are available.

Category: Vitamin B12
Routes represented: Subcutaneous (SubQ) / Oral / Sublingual
Storage context: Protect from light and follow the product label.

Authoritative overview

Published literature

No validated PubMed or DOI link is currently curated for this entry.

Safety evidence

Common or reported: injection-site reaction, rash or itching, mild diarrhea.

Serious or important: rare anaphylaxis, hypokalemia during rapid correction of severe deficiency.

Effects vary substantially by chemical form and route.

Safety evidence source

Interaction evidence

These are general, pairwise evidence notes. Green identifies the potential-synergy category, while Lv3/Lv2/Lv1 communicates evidence strength; it does not guarantee benefit or cancel a safety warning.

With metformin

Safety flag

Long-term metformin use can reduce vitamin B12 absorption and serum B12 concentration.

Interaction evidence source

With Folic acid

Complementary evidenceLv3

A randomized human trial found folic acid plus vitamin B12 lowered homocysteine more than folic acid alone.

Interaction evidence sourceCardiovascular outcome trialCardiovascular outcome trial

Summarised from published literature for reference only, with citations to the source. Evidence is graded as reported and is not a recommendation to combine, dose, or use any compound.

For personal tracking and education only. Not medical advice, diagnosis, or treatment, and not a medical device. Peptides may be prescription-only or unapproved where you live — consult a licensed healthcare professional.