hypothyroid and weight loss

[wrathsgirl]

I have been on 75mcg of levothyroxine for 7 weeks and I have noticed weight loss. My TSH was at 81.10 on Oct 2013. Before my blood work doctor put me on previous dose until test came back. I went back to doctor for a sinus infection and they want me to continue until mid December then another blood draw. Turns out I have had a severe sinus infection the same time I went in the weeks prior, took 2000mg og amoxicillin for 10 days. Anyway, they just ordered a Free T4? I have had thyroid issues for years and they have never gotten it right. My dilemma now is that I have no insurance and I go to the free clinic. The thyroid doctor I see only comes once a month,  so I have to wait.  Should I call and ask for a free T3 too? And has anyone experienced weight loss. Down about 10 pounds in 7 weeks. Has my metabolism changed? I feel much better but I usually have to workout forever to lose anything. I do have more energy, can't sleep much, just concerned... I never really understood how the T3 and T4 works. Thanks for reading.

[wrathsgirl]

Thank you for responding.  I feel much better.  I have not had any blood draws since October.  I will,  however,  ask about the T3 test on my next appointment.  Thanks so much.

[goolarra]

It sounds like you might be a bit overmedicated or that 75 mcg as a starting dose might have been a little too high.  It's often recommended to start lower and work up.  

Had you gained weight while hypo?  If so, it might be that extra weight coming off.  I lost about 25 lbs once on meds without doing anything differently.  I think it was the retained fluid draining.

They really should order FT3 as well as FT4.  However, given your circumstances, you might have a tough time convincing them of that.  Do you have any other blood work since the TSH of 81.10 in October?

T4 is produced by your thyroid.  It's the "storage" form of the thyroid hormones.  It floats around in your bloodstream until your cells need thyroid hormone.  However, cells can't use T4 until it is converted to T3, the "active" hormone.  Conversion happens throughout the body, but mostly in the liver.  Some people do not convert well, so even when FT4 levels are good, FT3 levels remain low, and symptoms remain.  So, it's very important to monitor FT3 since that's what correlates best with symptoms.  

It's always best to monitor FT3 right from the beginning to make sure it's tracking FT4 up the way it should.  However, if they give you a hard time about FT3, you can probably do without it for now.  When FT3 testing becomes really important is when FT4 is at midrange or higher, yet hypo symptoms remain.  That's when we start looking at FT3 as the culprit.