In children with a mild form of congenital hypothyroidism and an intact thyroid gland, giving iodine supplements does not change how their thyroid function develops over time, based on measurements taken after stopping iodine and during one year of monitoring.

In children with a mild form of underactive thyroid and an intact thyroid gland, taking iodine supplements for a year does not cause the thyroid to grow larger or change shape, based on ultrasound measurements.

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 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.

Giving children with mild thyroid hormone imbalance a daily iodine supplement within the recommended range for up to one year does not lead to the development of new antibodies targeting the thyroid gland.

Giving iodine supplements to pregnant women with mild iodine deficiency does not reduce the occurrence of isolated hypothyroxinemia or subclinical hypothyroidism, even when urinary iodine levels rise, suggesting the supplements do not resolve the underlying thyroid hormone imbalance.