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Thyroid UK
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Strange blood results - is there an explanation?

My endo requested a fresh blood test due to me taking all my meds the night before the last one.

The odd thing is my FT3 and TSH was higher when I didn't take T4 the night before:

Latest - T3 only - 10 hours before:

TSH 0.17 0.27 - 4.20 mIU/L

Free T4 13.40 9 - 26 pmol/L

Free T3 6.6 2.8 - 7.1 pmol/L

1 week earlier - T3 & T4 - 10 hours before:

TSH 0.04 0.35 - 4.50 mIU/L

Free T4 13.90 11 - 22 pmol/L

Free T3 5.4 3.9 - 6.8 pmol/L

I continued to have trouble sleeping when I took all my T3 at night so have been trying to take a split dose during the day for the last week. Unfortunately it is having the same effect as before and leaving me exhausted. When I took my morning dose at 7am this morning I fell asleep again and didn't wake until 10.15am. What do you think the problem might be?

My previous post with a bit more info:


21 Replies

Are your vitamin levels still optimal, if not tested recently you might want to consider retesting

Are you on strictly gluten free diet? You have Hashimoto's so it's very likely to help. Certainly would want to try it for 6 months. Ideally test TPO antibodies before starting and after 6 months. If antibodies lower then stick on it

Your FT4 is quite low. You might want to try slightly higher dose of Levothyroxine

What supplements do you take?


Both of these tests were done when I was taking 20mcg T3 and 150mcg T4 but my endo has now increased my T3 and reduced my T4 so current dose is 30mcg/125mcg.


Taking your T4 the night before the test won't have any effect on your TSH or FT3. It will only affect your FT4. And your FT4 was slightly higher when you took it at night, but not enough to worry about - possibly because you're taking T3 and so the FT4 is going to be low, anyway.

TSH and FT3 will be affected by the time of day, though. Did you have both blood draws at exactly the same time of day?


The first test was at 9.30am, the latest test was at 8.40am.


So, could account for the difference in TSH and FT3. Or else, it was just general fluctuation, which can happen to all results. But I don't think the differences are significant.

As to your sleeping problem, you probably need an increase in T3 - there room for a small increase. :)


Following these results my endo increased my T3 to 30mcg and reduced my Levo to 125mcg, which I have been taking for 10 days. I tried the full dose of T3 at night for 3 days but found it harder to fall asleep so have been trying 5mcg at night, 15mcg at 7am and 10mcg at 3pm for the last week. I felt better the first day of trying the new schedule but was back to being exhausted from the second day onwards.


How much T3 were you on before the increase?

Have you tried just splitting it into two doses? Splitting it into three really is spreading it a bit thin. And, remember, each time you take it, it needs to be on an empty stomach, one hour before eating or two hours after eating. :)


I was on 20mcg T3 with 150mcg T4.

No, I have only tried 3 doses but as I am taking half my dose at 7am, and that is sending me to sleep, how would that change if I only took 2 doses?


He increased you by too much for the reduction in levo. You should only increase T3 by 5 mcg every two weeks.

I don't understand why taking your full dose at night stops you sleeping, but taking half in the morning sends you to sleep. That's something I can't quite get my head round, and I'm sure there must be something other factor that we're not taking into account, here. Doesn't sound like it has anything to do with the T3.


I had 10 days at 25mcg T3 and 137.5mcg T4 before starting the full dose of 30mcg/125mcg so it wasn’t a complete shock to the system.

Could it be something as basic as a combination of increased body temperature following the T3 dose and the warm nights we’ve had for the last 4 or 5 weeks making it difficult to sleep? Or low in range cortisol, which I asked the endo to review once more but he dismissed and told me I really didn’t want to be taking HC? Or an ACTH issue, although never been tested? Or a ferritin issue, although I have good iron levels and above range haemglobin and haematocrit so can’t supplement?


It could very well be something to do with the heat. Perhaps not advisable to increase the dose in a heat wave. Have you tried taking all your T3 in the morning? You might have fallen asleep because the morning dose wasn't high enough. We have to experiment with timing to find what's right for us. :)


Not yet but will give that a shot in the morning.

Once changes are made to the timing of doses should the effects be almost instant or can they take a while to be noticeable? I.e. should I stick at 1 morning dose for a week or so to give it a chance?


You ought to stick to it for a while. Very little is instant with hormones. :)


Ok will try that.

Thanks for your help gg; good relevant advice as always.


You're very welcome. :)


That works for me too, more or less. If I take t3 in the early am around 3 or 4, I sleep again for another 3 or 4 hours easily and immediately. If I take it at night I have poor, interrupted sleep all night.

1 like

So do you take all your T3 at that time?

And do you also take T4?


No and no.


Did you also fast before test.

This is an excerpt:

Is TSH higher when fasting?

While fasting is not considered necessary when performing a thyroid blood test, studies have shown that early morning fasting translates to higher TSH levels, compared to those taken later in the day with no fasting.

Factors That May Affect Your Thyroid Test Results -



Yes I fasted for both.

Think the full link should be:



Are you on strictly gluten free diet?


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