Hashimoto’s disease, also known as Hashimoto’s thyroiditis, is an autoimmune disorder in which the immune system attacks the thyroid gland, gradually impairing its ability to produce thyroid hormones. Over time, this immune-mediated damage often leads to hypothyroidism, a condition characterized by insufficient thyroid hormone levels. Symptoms may develop slowly and can include fatigue, weight gain, cold sensitivity, dry skin, hair thinning, constipation, depression, and slowed heart rate. The exact cause is not fully understood but involves a combination of genetic predisposition and environmental triggers. Hashimoto’s disease is one of the most common causes of hypothyroidism and is typically identified through blood tests that measure thyroid hormone levels and thyroid-specific antibodies.