Too much iodine can cause both hyperthyroidism and hypothyroidism. Learn the safe upper limits and which supplements are most likely to cause iodine excess.
Excess iodine can disrupt thyroid function (hypo- or hyperthyroid symptoms).
| Standard | RDA | Upper Limit (UL) |
|---|---|---|
| US (FDA) | 150 mcg | 1100 mcg |
| EU (EFSA) | 150 mcg | 1100 mcg |
| AU (TGA) | 150 mcg | 1100 mcg |
| CN (CNS) | 150 mcg | 1100 mcg |
| JP (MHLW) | 130 mcg | 3000 mcg |
RDA = Recommended Dietary Allowance. UL = Tolerable Upper Intake Level. Exceeding the UL long-term may cause the toxicity symptoms described above.
Yes. Both too little and too much iodine can disrupt thyroid function. Excess iodine can trigger hyperthyroidism (rapid heartbeat, weight loss, anxiety) or hypothyroidism (fatigue, weight gain). The UL is 1,100 mcg/day for adults.
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Not medical advice. Always consult a qualified healthcare professional for personal medical decisions.