Is Selenium Safe with Propylthiouracil (PTU)?
Free · No account · based on published sources including NIH ODS, FDA drug labels, and peer-reviewed literature
Use selenium supplements cautiously alongside PTU. Notify your prescriber of all supplements and ensure thyroid function is monitored every 4–6 weeks during combined use.
Why this interaction occurs
PTU inhibits peripheral conversion of T4 to T3 via deiodinase inhibition. Selenium supplementation may partially counteract this effect by upregulating deiodinase activity, potentially reducing PTU efficacy.
Evidence
Evidence level: moderate.
Reported safety data
The FDA’s adverse event reporting system (FAERS) has received 2,262 reports mentioning Propylthiouracil (PTU). This reflects reported cases involving the medication in general — not confirmed causation, and not specific to the Propylthiouracil (PTU) + 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 Selenium interactions → · All Propylthiouracil (PTU) interactions →
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Educational only — not medical advice.
Always confirm with your doctor or pharmacist.