Is Zinc Safe with Levothyroxine?
Free · No account · based on published sources including NIH ODS, FDA drug labels, and peer-reviewed literature
2-4 hour separation is prudent; evidence for this specific pair is weaker than for iron or calcium.
Why this interaction occurs
Zinc may reduce levothyroxine absorption, but evidence is weaker than for iron or calcium. A 2–4 hour separation is reasonable.
Evidence
Evidence level: moderate.
Data source
FDA Levothyroxine Sodium label 2026; absorption interaction literature
Reported safety data
The FDA’s adverse event reporting system (FAERS) has received 302,514 reports mentioning Levothyroxine. This reflects reported cases involving the medication in general — not confirmed causation, and not specific to the Levothyroxine + 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 Zinc interactions → · All Levothyroxine interactions →
Already checked this one — check your whole list
Educational only — not medical advice.
Always confirm with your doctor or pharmacist.