갑상선기능저하증, or hypothyroidism, is a condition where the 갑상선 (thyroid gland) does not produce enough hormones. This can lead to a variety of symptoms, including fatigue, weight gain, and sensitivity to cold. It is often diagnosed through blood tests that measure levels of TSH (thyroid-stimulating hormone) and T4 (thyroxine). Treatment typically involves hormone replacement therapy, which helps restore normal hormone levels in the body. Regular monitoring and adjustments to medication may be necessary to ensure effective management of the condition. Early diagnosis and treatment can significantly improve quality of life for those affected.