Hypothyroidism is a condition where the thyroid gland, located in the neck, does not produce enough thyroid hormones. These hormones are essential for regulating metabolism, energy levels, and overall body functions. When the thyroid is underactive, people may experience symptoms like fatigue, weight gain, and sensitivity to cold. This condition can be caused by various factors, including autoimmune diseases like Hashimoto's thyroiditis, certain medications, or iodine deficiency. Treatment typically involves taking synthetic thyroid hormones to restore normal hormone levels, helping individuals feel more energetic and balanced in their daily lives.