Thyroid nodules shrinking by 3mm can be caused by the inflammation subsiding and iodine intake recovering, etc. The cause of the disease needs to be clarified and treatment should be carried out. 1. Inflammation subsides: If the thyroid nodules are caused by inflammation, the nodules will gradually decrease in size as the inflammation subsides, which is a sign that the condition has improved and requires regular checkups. 2. Recovery of iodine intake: when the intake of iodine is too little, not enough for the body, it will cause thyroid nodules, generally after a period of dietary adjustment, increase iodine intake, nodules may become smaller, regular review can be. To summarize, the shrinking of thyroid nodules is mostly a sign of improvement of the disease, so there is no need to worry too much, but you should still go to a regular hospital, do a formal examination, listen to the doctor’s advice, and then consider whether to treat the problem.