Thyroid UK

Confused. TSH lower, FT4 higher but FT3 dropped to below range

Thanks to the advice from here, i got my levo raised to 50mg 6 weeks ago but the new results have confused me.

I was diagnosed Hashimotos in the summer of 2016 with sky high antibodies but didn't get medicated until October.

Back then my TSH was 4.3 and FT4 was 13.57. My B12 was 301 and vit d was 88.

I went on iron supplements when my ferritin was 10 and got it up to 46. I'm not taking iron now.

I'm still feeling like I'm running at half speed to the point I go to bed in the afternoon when I'm not at work. I suffer brain fog, fatigue, a feeling of being jet lagged, constipation and have numbness and pins and needles and leg cramps.

Early December results on 25mg, after fasting and taken at 11.30am. I took my Levo 24 hours before this blood test. The previous results were taken at 9am.

Those results were much improved:

TSH 1.7 range is 0.35 to 4.5

FT4 17.5 range is 11 to 26

FT3 3.9 range is 3.1 to 6.8

I take selenium, k2mk7 with vitD, magnesium recently B12 and B complex and eat GF. I'm trying to get these ranges all optimum.

Now taking g 50mg my results were taken at noon and fasting.

B12 1149 (range 197 to 771

Foliate 8.8 (range <3)

Albumin 45 (range 35 to 50)

Calicum 2.21 (range 2.1 to 2.55)

Adjusted Calcium 2.11 (range 2.2 to 2.6) marked low

Ferritin 50 (15 to 150) ill start supplementing again and add vit c

TSH 0.78 (.35 to 4.5)

FT4 18.4 (11 to 26)

FT3 3.7 (3.9 to 6.8) that's worse that last time even though FT4 had increased

Cortisol serum at noon was 243 but don't have a range.

I can see I'm not converting well and endo is open to adding T3.

Perhaps I should test for DIO2 as I'm concerned for my daughter too?

Does anyone know why my FT3 would be this low? I have had chronic stress for over a year with worries of my daughter's health and wonder if that could be a factor.

Really appreciate any views as I can't see T4 improving this. Many thanks in advance!

6 Replies


Why do you need to pay for the DIO2 test? You can see that you aren't converting well because FT3 is below range.

The high TSH 4.3 will have flogged your thyroid to produce T3 and now that TSH is lower your thyroid is producing less T3 and you are converting less T3 from T4.

Next time you have a thyroid test arrange for it to be done early in the morning when TSH is highest, and fast (water only), as TSH drops after eating and drinking.


Thanks. I do fast from the might before the test with only water but my endo doesn't do early appointments and my GP won't test FT3! Do you think the time would make a big difference?



It makes a big difference to TSH. See the graph in


Thanks. I guess that indicates I could have more t4 and additional t3. I'll ask my GP if he'll do an early morning test with T3 as I have evidence I'm not converting well. The reason I thought of having the genetic test is I'm worried about my daughter's thyroid so being informed about me might help. The doctors sadly haven't helped her. Many thanks.



You don't need another FT3 test. Your FT3 is below range so you don't need a test to show you are a poor converter. You having a genetic impairment doesn't mean your daughter has the same impairment so how will it help her for you to have DIO2 test?

Increasing T4 to 75mcg will improve FT4 and FT3 but may not raise FT3 enough and you may need T3 as well.


Ok thanks. I'm seeing my endo late March so I'll try to get my t4 raised and some t3.


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