Thyroid is considered to be one of the largest endocrine glands in the body. This thyroid gland is located in the front part of the neck just below the thyroid cartilage (Adam’s apple). This gland produces thyroid hormone which is very important for stimulating the metabolism and growth of the body. For this, the thyroid needs iodine which is being taken from the food and water. The entire body contains about 50mg of iodine. In this, about 1/5 to 1/3 is stored in the thyroid. This iodine is then combined with the tyrosine by thyroid leading to the release of the hormones. As one grows older, this thyroid gets lumpier and its frequency increases with age. This causes either hyperthyroidism or hypothyroidism. The most common symptoms include irritability, nervousness, muscle weakness, weight loss, sleep disturbances, eye irritation and vision problems. This disease is more common in women than men. The thyroid also produces the hormone, calcitonin which plays a major role in calcium homeostasis. This is controlled by hypothalamus and pituitary. Since this thyroid hormone also directly involved in the functioning of other parts of the body, any defects in it greatly affects other organs also. Hence treating it is essential; else it leads to cardiovascular disease, osteoporosis and infertility.