The thyroid is a small, butterfly-shaped gland found at the front of your neck. It produces hormones—mainly T3 (triiodothyronine) and T4 (thyroxine)—that control how your body uses energy. When the thyroid doesn’t produce enough hormones (hypothyroidism), your body’s processes slow down. On the other hand, when it produces too much (hyperthyroidism), your body can go…