Phreezer is right. However, I can at least give some info. Of course, everyone is different and will react differently. Being so small she would probably need less. A proper doc would start her out on the lowest dose and then retest in a month. She may be able to go with straight T4 (synthroid type) or need a combo like Armour (T3/T4 combo). Here's where it gets tricky. Almost every doc I know will check the TSH and if it's in the norm they won't check anything else. If it is out of whack they will check T4 but will NOT check T3 unless the T4 is out of whack. This is messed up because T4 converts into T3 and just because you have plenty of T4 does NOT mean you have plenty of T3...it's possible the enzyme needed for conversion is not being made in sufficient quantities. So, yer gonna have to convince the doc to check TSH, T4, T3, free T4 and free T3. AND yer gonna have to have the doc TELL the lab to do those tests. The labs often won't
test them all unless they are told they need to. Again, the T3 not being tested blah blah.
Good luck bro