Long-term antacid use depletes B12
Stomach acid is required to release B12 from food proteins. Long-term PPI use (>2 years) increases B12 deficiency risk by 65%. Can cause anemia, neuropathy, cognitive decline. Sublingual B12 bypasses this issue.
Monitor B12 levels if on long-term PPIs. Consider sublingual or injection B12.
Use sublingual B12 which doesn't require stomach acid
Long-term antacid use depletes B12. Monitor B12 levels if on long-term PPIs. Consider sublingual or injection B12.
Use sublingual B12 which doesn't require stomach acid
This interaction is rated “Warning” by Formulate. Stomach acid is required to release B12 from food proteins. Long-term PPI use (>2 years) increases B12 deficiency risk by 65%. Can cause anemia, neuropathy, cognitive decline. Sublingual B12 bypasses this issue.
Studies from our registry that mention antacids or vitamin b12. Each links to the primary source and the other Formulate pages citing it.
Mentions vitamin b12 · 2014
The prevalence of cobalamin deficiency among vegetarians assessed by serum vitamin B12
Pawlak et al. · European Journal of Clinical Nutrition
Systematic review finding B12 deficiency prevalence of 62% in pregnant vegetarian women, 86% in elderly vegetarians, 41% in adolescents.
Mentions vitamin b12 · 2013
Vitamin B12 deficiency
Stabler SP · New England Journal of Medicine
Comprehensive clinical review of B12 deficiency diagnosis and treatment, noting that serum B12 alone is unreliable and that methylmalonic acid (MMA) and homocysteine are more sensitive markers of functional deficiency.
Mentions vitamin b12 · 2005
Oral cyanocobalamin supplementation in older people with vitamin B12 deficiency: a dose-finding trial
Eussen SJ, de Groot LC, Clarke R, et al. · Archives of Internal Medicine
Dose-finding RCT in older adults found 647–1,032 µg/day oral B12 was needed to normalize mild B12 deficiency markers — orders of magnitude above the RDA, supporting high-dose oral as an alternative to injections.
Guide
Vitamin B12 Guide 2026: Which Form & Dose You Need
Find out if you’re actually B12 deficient — and why standard tests miss it. Covers methylcobalamin vs cyanocobalamin, dosing, and the MMA test.
Review
Methylcobalamin vs Cyanocobalamin: Which B12 Form Actually Works
Most B12 supplements use cyanocobalamin — but methylcobalamin is the bioactive form. Here's when the difference matters and when it doesn't.
Other interactions to know
Long-term PPI use reduces B12 absorption
High-dose vitamin C may reduce B12 absorption
Antacids significantly reduce iron absorption
PPIs impair magnesium absorption
B12 and folate work together in methylation
Antacids reduce calcium absorption
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Medical disclaimer. This page is for educational purposes only and does not replace advice from a qualified healthcare provider.
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