Many patients ask the same question: “Should I take iodine-free salt or not?” In fact, neither too high nor too low iodine intake is recommended by WHO: 150 μg of iodine per day for adults, 70 μg per day for those under 4 years of age, and 200 μg per day for pregnant women and lactating mothers. Under normal physiological conditions, the amount of iodine excreted is equal to the amount of iodine ingested. Urinary iodine below 150ug/L indicates iodine deficiency and above 300ug/L indicates excess iodine, which can be harmful to the thyroid gland.