If your free t4 is high in
normal range, yet your t3 is very low, then you probably have problems with converting.The problem is, many Synthroid prescribing doctors (endos.) usually never check it and just assume you're converting the t4 into enough t3 on your own. Also, your TSH is still a little elivated, even though it is in range. Many people feel better when this is slightly lower-say arond 2.0 or even lower. These ranges are very broad, so it matters where you fall within them.