The thyroid is a small gland in your neck located just below the Adam’s apple. It releases hormones, thyroxine (T4) and triiodothyronine (T3). These hormones help in increasing the amount of oxygen your body uses and stimulate your cells to produce new proteins.
Too much thyroid hormone results in a condition known as hyperthyroidism it can make a person feel nervous or anxious, weight loss and be hyperactive. Insufficient hormone production leads to hypothyroidism which can cause such fatigue and weight gain. Here is a video to know and understand thyroid causes and symptoms better.