Overactive thyroid. It is called hyperthyroidism. Some symptoms are difficulty concentrating, fatigue, large thyroid in neck, frequent bowel movements, increased appetite, heat intolerance, increased sweating, irregular menstrual periods in women, nervousness, restlessness, weight loss, high blood pressure, hair loss, tremors, itching, diarrhea, upset stomach, eyes protruding (exophthalmos).
Hyperthyroidism. Overactive thyroid (hyperthyroidism) is due to excess amounts of thyroid hormone. Symptoms include weight loss, feeling hot, tremors, fast heart beating, anxiety, trouble sleeping, more bowel movements, muscle weakness, light periods. Diagnosis is made through blood testing of tsh, t4, and T3 (liothyronine) levels.