Is Tyrosine Safe with Levothyroxine?
Free · No account · based on published sources including NIH ODS, FDA drug labels, and peer-reviewed literature
Separate tyrosine supplements from levothyroxine by at least 2–4 hours. Inform your healthcare provider if you are using high-dose tyrosine products (>500 mg/day).
Why this interaction occurs
Tyrosine is a structural precursor to thyroid hormones and catecholamines. While direct interaction evidence is limited, high-dose tyrosine may theoretically influence thyroid axis signaling and could affect absorption timing if taken simultaneously.
Evidence
Evidence level: limited.
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 Tyrosine interactions → · All Levothyroxine interactions →
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Educational only — not medical advice.
Always confirm with your doctor or pharmacist.