T4 (Levothyroxine) is a Thyroid hormone — prohormone (converted to active T3) researched for Deiodinase / T4→T3 Conversion Research, Primary Hypothyroidism Models, HPT Axis / TSH Feedback Research. QSC supplies T4 to researchers across California with domestic USA shipping and Janoshik COA verification.
Levothyroxine (T4) is the main secretory product of the thyroid gland and the most abundant circulating thyroid hormone. T4 itself has minimal thyroid receptor affinity — it is a prohormone. Peripheral deiodination by type 1 and type 2 deiodinase (DIO1, DIO2) converts T4 to the active T3 in liver, kidney, and other tissues. Approximately 20% converts to reve… Full T4 Research Hub →
