Thyroid disorders generally fall into two categories: an underactive thyroid (hypothyroidism) or an overactive thyroid (hyperthyroidism). If your thyroid is underactive, you might experience fatigue, weight gain, dry skin, and feeling cold. If it is overactive, symptoms often include anxiety, weight loss, a rapid heartbeat, and heat intolerance. Fortunately, these conditions are highly treatable. For an underactive thyroid, doctors commonly prescribe daily hormone replacement therapy, such as levothyroxine. For an overactive thyroid, antithyroid medications like methimazole or propylthiouracil are used to reduce hormone production, sometimes alongside beta-blockers to manage symptoms. With proper medication, most people manage thyroid conditions easily and live completely normal, healthy lives.