In children aged 7 to 14, elevated TSH levels are common and stay above 10% regardless of whether iodine intake is 200–300 micrograms per day or higher, indicating that TSH levels alone cannot reliably signal too much iodine in this group.

In children with mild thyroid hormone imbalances, taking iodine supplements that gradually increase from 50 to 150 micrograms per day for nine months leads to a measurable increase in TSH hormone levels, but does not change other thyroid markers or cause clinical harm.

In children with a specific genetic mutation (DUOX2) and mild thyroid underactivity not caused by autoimmunity, taking iodine supplements within the range of 50–150 micrograms per day does not bring thyroid hormone levels back to normal, because thyroid-stimulating hormone (TSH) stays high.

In Chinese children between 7 and 14 years old, consuming iodine at levels of 250–399 micrograms per day is linked to a higher likelihood of developing an enlarged thyroid gland, with higher intake levels corresponding to greater risk.

In children aged 7 to 14, higher iodine intake is associated with a predictable rise in thyroglobulin levels, but the proportion of children with very high thyroglobulin levels stays above 3% regardless of how much iodine they consume, suggesting that this measure cannot reliably identify excess iodine.

In children aged 7–14, the size of the thyroid gland and the presence of goiter are better signs of thyroid stress caused by too much iodine over time than blood levels of thyrotropin or thyroglobulin, because they change more consistently with the amount of iodine consumed.