Is Vitamin B12 (Cobalamin) Safe with Ethinyl estradiol?
Free · No account · based on published sources including NIH ODS, FDA drug labels, and peer-reviewed literature
Consider monitoring serum B12 levels periodically. Supplement with 500–1000 mcg of B12 daily (methylcobalamin preferred) if levels are low or if neurological symptoms such as tingling or fatigue are present.
Why this interaction occurs
Estrogen-containing contraceptives have been shown to reduce serum B12 concentrations, possibly by altering binding proteins or absorption. Long-term deficiency can impair neurological function and red blood cell production.
Evidence
Evidence level: moderate.
Reported safety data
The FDA’s adverse event reporting system (FAERS) has received 240,329 reports mentioning Ethinyl estradiol. This reflects reported cases involving the medication in general — not confirmed causation, and not specific to the Ethinyl estradiol + supplement combination on this page.
FAERS reports are voluntary and cannot prove that a drug caused an event. Do not use report counts to assess the safety of this specific drug-supplement pair.
Frequently asked questions
Related interactions
All Vitamin B12 (Cobalamin) interactions → · All Ethinyl estradiol interactions →
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Educational only — not medical advice.
Always confirm with your doctor or pharmacist.