Thyroid UK
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Latest bloods help please

I've been taking Levothyroxine for the past 5 months (25mcg for the first two weeks &50mcg for the remaining time) I had a blood test in December & my TSH had decreased from 7.2 to 2.8 (0.30-4.20)

I asked my GP for a increase however she wanted me to continue on the same dose for a little longer to see if I would get any further improvement. She also wanted to check my FT4 level.

I had another blood test last week & my TSH is now 2.6 (0.30-4.20). The FT4 was 14.00 (12.00-22.00) My original test in September showed a FT4 of 11.5

She agreed to an increase in Levothyroxine to 75mcg in order to see if I feel better. I have seen some improvement in how I feel since starting treatment but I certainly don't feel great. I've also been addressing my low b12, folate & ferritin thanks to the advice given here.

I'm interested to know if it's normal to see a good reduction in TSH but only an small increase in FT4 when starting on Levothyroxine.

Any thoughts?

2 Replies

Hi Jane,

It's still rather early days in your dose increase and we do find that it can take some time for FT4 to hopefully elevate into the upper quadrant.

Your doctor shoulr re-test in 6-8 weeks to give the hormone enough time to settle. It's good that she is testing FT4 but as you have probably read around the site , it's important to know what the FT3 level is as this is the important "active" component that does it's magic around the body. Knowing the T3 level is good because it tells us if you are good at converting T4 to T3. Again this should be in the upper range for it to be effective in your biology.

Unfortunately very few GP's or their labs will test T3 so we have to take ourselves to self-testing with Blue Horizon or Medicheck.

I think it took me around a year for the titration process to sort itself out and in the end I was achieving an FT4 a digit or two off the top of the range and not too shabby conversion. I have been taking selenium for the past couple of months to see if that helps. My TSH is a shade off suppressed, so I'm optimally medicated on 100mcg (I have Hashimoto's).

I'm afraid having hypothyroidism is very much a situation of hurry up and wait. :)

Don't forget that when you have your bloods done, early as possible appointment (preferably before 9am), fasted, no levo for 24 hours before appointment and take your daily dose after your blood draw.


This is how I think it works, tho' others may explain it better.

You were taking 50mcg of levo (a relatively low dose), and this will have added to your free t4. But the levo will have been spotted by the pituitary which has in turn reduced your tsh. So, the tsh has gone down; in other words your pituitary is not screaming as loudly to your thyroid to produce the hormones. So your own thyroid produces less.

The net result is a reduction in your tsh but only a small rise in free t4. Your doctor has quite correctly increased your levo dose. Now you have to wait, as Spongecat so brilliantly described.


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