There is usually no way to distinguish between Hashimoto’s hypothyroidism and hypothyroidism in general; both are hypothyroidism. Hashimoto’s hypothyroidism is subordinate to hypothyroidism, and there is no difference in thyroid function between the two. Generally, the higher the TSH (thyroid-stimulating hormone), the lower the T3 (serum total triiodothyronine) and T4 (thyroxine serum total thyroxine), suggesting that hypothyroidism is more severe. The presence of clinically elevated TSH but normal T3 and T4 is called subclinical hypothyroidism. If a distinction must be made between the severity of the conditions, it depends on the degree of reduction in thyroid function rather than the two diseases themselves. Hashimoto’s disease is one cause of hypothyroidism, but not the only one. For example, subacute thyroiditis, iodine-131 treatment for hyperthyroidism, and in some patients, removal of a large portion of the thyroid gland due to thyroid nodules or tumors can lead to hypothyroidism. No matter what type of hypothyroidism is present, it should be treated appropriately under the guidance of a specialist.