This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Endocrinology and breast, Subject name: Surgery
All of the following statements regarding T3 (Tri-iodothyronine) are true Except 
Select and explain. 
A. Half-life of T3 is only few hours, B. Only 20% of the total T3 is produced by the thyroid, C. T3 is usually given as 100 mg once daily, D. T3 is the active form of the hormone and is produced in the periphery by conversion from T4
C: T3 is usually given as 100 mg once daily
Answer: C: T3 is usually given as 100 mg once daily 
Explanation: OUnbound free T4 and T3 (0.03 and 0.3 percent of the total circulating hormones, respectively). OT3 is the more impoant physiological hormone and is also produced in the periphery by conversion from T4. OT3 is quick acting (within a few hours), And T4 acts more slowly (4-14 days). OT3 is given three times daily, usually as a suppressive dose of 20 mg three times a day.O T4 is given once daily