Iodine + Selenium

Can you take Iodine and Selenium together?

SynergyMechanism-based

Yes — the thyroid needs both, but don't exceed either upper limit.

What to do. Keep doses moderate. With thyroid disease, involve your doctor.

Mechanism

Both are needed for thyroid hormone

Iodine is built into thyroid hormone; selenium-dependent deiodinases convert T4 to active T3 and protect the thyroid from oxidative damage.

Evidence: Mechanism-based — Plausible biological mechanism with little direct human outcome data.

  1. 01NIH Office of Dietary Supplements — Iodine Fact Sheet for Health Professionals
  2. 02NIH Office of Dietary Supplements — Selenium Fact Sheet for Health Professionals

Timing

A day with Iodine and Selenium

  1. 08:00

    Breakfast

    with meal

Taking more than these two?

Add the rest of your stack and your medications for a complete check.

Check my full stack

Buying guide

What to look for on the label

  • Iodine

    • Potassium iodide at ≤150 mcg
    • Avoid high-dose kelp unless supervised

  • Selenium

    • Selenomethionine or selenium yeast
    • Count selenium in your multivitamin too

Related

Other interactions

Selenium + Vitamin E

Complementary antioxidant systems

Synergy→

Learn more about Iodine and Selenium.