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Iodine (Thyroid) Side Effects & Safety

Evidence:Strong
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This content is for informational purposes only and does not constitute medical advice. Statements about dietary supplements have not been evaluated by the FDA and are not intended to diagnose, treat, cure, or prevent any disease. Individual results may vary — consult your healthcare provider before starting any supplement. Full disclaimer

Safety Profile

Overall safety rating: Safe with Caution

Potential Side Effects

  • Metallic taste in mouth
  • Nausea and stomach upset at higher doses
  • Excess iodine can trigger or worsen hypothyroidism or hyperthyroidism (Wolff-Chaikoff effect or Jod-Basedow phenomenon)
  • Acne-like skin eruptions (iododerma) at high doses

Drug & Supplement Interactions

  • May interfere with levothyroxine and other thyroid medications — monitor TSH
  • Lithium combined with iodine increases hypothyroidism risk
  • ACE inhibitors and potassium-sparing diuretics combined with potassium iodide may cause hyperkalemia

Maximum Dose

Do not exceed: 1,100mcg (1.1mg) daily Tolerable Upper Intake Level for adults (IOM)

Full Iodine (Thyroid) Guide

References

  1. Zimmermann MB (2009). Iodine deficiency. Endocrine Reviews. DOI PubMed
  2. ReviewZimmermann MB, Jooste PL, Pandav CS (2008). Iodine-deficiency disorders. The Lancet. DOI PubMed
  3. ReviewSpallek L, Krille L, Reiners C, Schneider R, et al. (2012). Adverse effects of iodine thyroid blocking: a systematic review.. Radiation protection dosimetry. DOI PubMed
  4. RCTReinhardt W, Kohl S, Hollmann D, Klapp G, et al. (1998). Efficacy and safety of iodine in the postpartum period in an area of mild iodine deficiency.. European journal of medical research. PubMed