When your body lacks sufficient thyroid hormone, it can cause your body to suffer from hypothyroidism. The thyroid hormone is designed to keep your metabolism running, so if you're suffering from the condition it can cause all sorts of symptoms associated with a slow metabolism. These symptoms include feeling tired, weight gain or having trouble losing weight, coarse dry hair, hair loss, dry or rough skin, intolerance to temperature, constipation, depression, memory loss, abnormal menstrual cycle, decreased libido and muscle cramps.