My autoimmune disease causes my body to attack my thyroid, which then has difficulty producing the hormones my body needs. With Synthroid & levothyroxine, I did not have the control that my compounded T3/T4 medication provides. The Synthroid only addresses one piece of the thyroid puzzle. My compounded medication helps me address the whole picture. I have more energy now for everything. I wasn't getting that with Synthroid.