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Iodine — Frequently Asked Questions

This content is for informational purposes only and does not constitute medical advice. Consult your healthcare provider before starting any supplement. Full disclaimer

Frequently Asked Questions

Do I need an iodine supplement if I use iodized salt?

Probably not. A quarter teaspoon of iodized salt provides about 71mcg of iodine. If you use iodized salt regularly and eat some seafood or dairy, you likely meet the 150mcg RDA. However, if you use sea salt, Himalayan salt, or restrict salt intake, you may need a supplement.

Can too much iodine be harmful?

Yes. Excess iodine can paradoxically cause both hypothyroidism (Wolff-Chaikoff effect) and hyperthyroidism (Jod-Basedow phenomenon). This is particularly risky for people with pre-existing thyroid conditions. The upper limit is 1,100mcg daily for adults. Avoid high-dose iodine supplements (>500mcg) unless directed by a physician.

Is kelp a good source of iodine?

Kelp is extremely rich in iodine, but this is a double-edged sword. Iodine content in kelp supplements varies dramatically (45-57,000mcg per gram depending on species), making precise dosing difficult. Some kelp products have been found to contain iodine levels far exceeding the upper limit, risking thyroid toxicity. Potassium iodide supplements offer more consistent dosing.

Full Iodine Guide

References

  1. (). Effect of inadequate iodine status in UK pregnant women on cognitive outcomes in their children. The Lancet. DOI
  2. (). Iodine-deficiency disorders. The Lancet. DOI
  3. (). Consequences of excess iodine. Nature Reviews Endocrinology. DOI