Hello and thank you for asking! Hypothyroidism, also called underactive thyroid or low thyroid, is a common disorder of the endocrine system in which the thyroid gland does not produce enough thyroid hormone. Too little iodine in the diet is the most common cause of hypothyroidism, but in people using iodised salt with enough iodine in the diet, the most common cause of hypothyroidism is the autoimmune condition Hashimoto s thyroiditis. As the condition is autoimmune hence only treatment is to provide external thyroxine to body. Most people with hypothyroidism symptoms and confirmed thyroxine deficiency are treated with a synthetic long-acting form of thyroxine, known as levothyroxine (L-thyroxine), You would be started with a dose of recommended by your treating physician,daily empty stomach and check the thyroid hormones 6 weeks after. In case you need more explanations, i would be happy to help. Thanks