Should I be treated of a low Free T3

[snowyval]

I have been trying to lose a significant amount of weight (60 lbs).  For over 6 months now I have been working out 5-6 days a week (70 min. on the elliptical runner, followed by 25-30 min of resistant/weight training) and I have only lost 10 pounds.  I have a very "clean diet" and my calorie count ranges from 1200-1500/day.  I have been trying to build some muscle, but am finding it difficult, (I am perimenopausal and found out my testosterone is low (<10, lab normals 20-130 ng/dL) which is probably why.  My TSH is 1.6 (lab normal 0.5-3.0) Free T4 is 0.9 (lab normal 0.7-2.4ng/dL)
Free T3 is low at 1.8 (lab normal 2.5-6.5pg/ml)  I'm have been quite fatigued and very often can fall asleep at the drop of a hat!  Really the only symptoms of hypothyroidism I have are the fatigue, very slow weight loss, mental fogginess and really needing to push myself to do what needs to be done.  Is my Free T3 result significant enough to warrant treatment?   YFI: Saliva Cortisol is normal in the morning, but drops below normal for the remainder of the day.
Thank you.

[goolarra]

Your FT3 is definitely low enough for treatment.  FT4 is also quite low.  TSH is the only number that is "normal".  FT3 correlates best of the three with symptoms, followed by a distant FT4, and TSH barely makes it into the race.  However, TSH was the gold standard for so long that it's often hard for us to get our doctors to treat based on FT3 and FT4 and symptoms.  

With your symptoms, I think you would definitely benefit from being on meds.  If you can't get your doctor to agree, you might have to find another doctor.  I don't imagine it will be very long before your TSH becomes abnormal.

[snowyval]

Thank you so much for your input.  I'm trying to get as much information as
I can before I make an appointment to see her.  

[goolarra]

For many years the most reliable and economical test of thyroid funtion was TSH.  Doctors used it because there was nothing else.  However, testing FT3 and FT4 has now become both accurate and cost-efficient.  Apparently, many doctors have not picked up a medical journal since med school and have not caught up with that fact.

Why would anyone look at a pituitary hormone (TSH) to see what the thyroid is doing when they can look at the thyroid hormones themselves (FT3 and FT4)?  It just doesn't make a lot of sense.  So many people are either not treated or inappropriately treated because doctors are treating TSH only.

Good luck!