High thyroid T3 and T4 may be caused by hyperthyroidism, or it may be caused by taking levothyroxine sodium tablets, it is recommended to consult a doctor. 1. Elevated T3 and T4, if accompanied by a decrease in TSH, can be considered to be caused by hyperthyroidism, which requires a clear diagnosis and active application of antithyroid drugs for treatment. 2. Hypothyroidism patients generally need to take levothyroxine sodium tablets, if the dose is too large, may affect the body’s T3, T4, it is recommended that under the guidance of a doctor to take reasonable medication. Patients with elevated thyroid T3 and T4 are advised to seek prompt medical attention, make a clear diagnosis under the guidance of a doctor, and take active treatment.