How can you shrink a thyroid nodule?

You can't : Thyroid nodules don't shrink, and there is no medicine or other treatment that will shrink them short of surgical removal.

Options: It depends on what the nodule is doing. Surgery is the most effective way to remove symptomatic thyroid nodule, however, not all patients are surgical candidates, so alternative treatment options are needed. If the nodule is a hot nodule, you can shrink it with radioactive iodine. Percutaneous ethanol injection (pei) is also an option (although not commonly done anymore).

Depends on the cause: If a nodule is due to hashimoto's thyroiditis (inflammation caused by autoimmunity, where one's own immune system attacks one's proteins and tissues), then taking thyroid hormone pills can shrink it. If it's a tumor that's over-producing thyroid hormone, radioactive iodine can kill it, and make it smaller). Fluid-filled cysts can be drained with a needle, but may grow back. Cancer needs surgery.