was macht l thyroxin im körper — what are common causes?

L-thyroxine (levothyroxine) is the synthetic form of the thyroid hormone thyroxine (T4). In the body, it is partially converted to the active hormone T3 (triiodothyronine), which regulates metabolism, heart function, body temperature, and growth. The most common reason for taking L-thyroxine is hypothyroidism (underactive thyroid). Common causes of hypothyroidism include: Hashimoto's thyroiditis (autoimmune disease), iodine deficiency, surgical removal of the thyroid, radioactive iodine therapy, congenital thyroid abnormalities, or certain medications. L-thyroxine is also used for benign goiter or TSH suppression after thyroid cancer. Important: Dosage must be individually adjusted; over- or underdosing has health consequences. Evidence for efficacy in overt hypothyroidism is strong (standard therapy), but for subclinical hypothyroidism or other indications the data are more nuanced. Note: L-thyroxine is not a dietary supplement and should only be taken under medical supervision.