Is Iodine Safe with Liothyronine?
Free · No account · based on published sources including NIH ODS, FDA drug labels, and peer-reviewed literature
Avoid supplemental iodine doses exceeding the recommended daily intake (150 mcg/day) unless medically supervised. Inform your prescriber if you are taking iodine-containing supplements such as kelp or povidone-iodine products.
Why this interaction occurs
Since Liothyronine (T3) bypasses iodine-dependent synthesis, excess iodine primarily affects residual thyroid gland function. In patients with any remaining thyroid tissue, high iodine intake may cause erratic thyroid hormone output, complicating Liothyronine dose titration.
Evidence
Evidence level: moderate.
Reported safety data
The FDA’s adverse event reporting system (FAERS) has received 8,329 reports mentioning Liothyronine. This reflects reported cases involving the medication in general — not confirmed causation, and not specific to the Liothyronine + 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 Iodine interactions → · All Liothyronine interactions →
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Educational only — not medical advice.
Always confirm with your doctor or pharmacist.