Swelling and puffiness, especially around the eyes and face, known as "myxedema."
High levels of LDL cholesterol (the "bad" cholesterol) due to slowed metabolism.
Unexplained weight loss, despite increased appetite and food intake.
Palpitations, rapid heart rate, or irregular heartbeat (arrhythmia).
Feeling anxious, nervous, restless, or irritable, often without an obvious cause.