Best Answer - Chosen by Voters
the thing to consider here is that a defect in thyroid gland can either cause it to be working too much (hyperthyroidism) or not working enough (hypothyroidism)
in hyperthyroidism (too much thyroid hormone), symptoms include: high heart rate, palpitations (feeling your heart pumping too fast), chest pain, tremors and shakiness, weight loss, diarrhea, increased reflexes, warm moist skin, fine hair, heat intolerance (getting hot easily)
hypothyroidism (not enough thyroid hormone), symptoms include: cold intolerance (getting cold easily), low activity, slow reflexes, weight gain, constipation, weakness, swelling around the eyes or face, dry cool skin, coars brittle hair
Source(s):
med student; Merck Manual