The most common thyroid problems include hypothyroidism and hyperthyroidism.

Hyperthyroidism is caused by an overproduction of thyroid hormones T3 and T4. When these hormones are over produced, it can lead to an increase in your metabolism, which can cause accelerated weight loss and heart rate irregularities.

Hypothyroidism is due to an under production of thyroid hormones. When T3 and T4 hormones are under produced, it can lead to a decrease in your body's metabolism, leading to weight gain and slowed heart rate. Both these conditions can lead to serious health problems if not addressed on time.

Common causes of thyroid problems include Hashimoto's thyroiditis and Graves' disease.

Hashimoto's thyroiditis is an autoimmune disorder that leads to inflammation in the thyroid, causing hypothyroidism. It is often a condition that is hereditary. Typically, there is no cure, but when it leads to hypothyroidism, it can be treated with medication.

Graves' disease is an autoimmune disease that leads to over activity in the thyroid, causing hyperthyroidism.