Thyroid disease symptoms, free ebook. As many as 25 million Americans have hypothyroidism. About half of them have no idea that they do! Millions more suffer this condition around the world. Hypothyroidism is the medical name for when your thyroid gland doesn't produce enough hormone. he thyroid gland controls your entire body's metabolism. That means that your weight, your hair, your skin, your sex drive, all sorts of things that go on in your body depend on your thyroid to work right.