Blood results with 100mcg T4/25mcg T3 - Thyroid UK

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Blood results with 100mcg T4/25mcg T3

Grundywhiffs01 profile image

Hi everyone.

I wanted some advice regarding my last blood results. I was taking 100mcg T4 and 25mcg T3, both first thing in the morning, on an empty stomach with water. I know its advised to leave 24 hours for T4, and 12 hours for T3, before having the blood drawn, but as i take all my T3 in the morning, it was 24 hours after both.

My numbers were...

TSH - 0.231 ( 0.27-4.2)

FT4 - 15.2 (12-22)

FT3 - 6.38 (3.1-6.8)

On this dose i felt pretty good, temperature sitting around 37 (98), although slightly irritable and anxious. So my question is, would you say that as I left 24 hours after T3, and it is still very close to the top of range, that it is generally sitting above range throughout the day? Also, id like to get T4 slightly higher, and T3 to around 5.5, so how would i best dose to achieve this?


12 Replies
SeasideSusie profile image

By leaving 24 hours between last dose of T3 and blood test, your FT3 is showing lower than the normal circulating amount (you have a false low). So if you'd taken T3 at the advised time before blood draw (8-12 hours) then your FT3 would very likely be over range which would mean that you are taking too much T3. I take my Levo and T3 (one dose) together early in the morning. When I do tests, I split my T3 dose, take half 24 hours before the time of my blood draw and the other half usually around 10 hours before.

It's not recommended to change both Levo and T3 at the same time. If I wanted to do what you want, I would reduce T3 by 6.25mcg now, wait 2 weeks then add an extra 12.5mcg Levo. Retest after 6 weeks and see where your levels lie and how you feel.

Thanks Susie. Much appreciated.

Does just reducing T3 dose, cause an increase in FT4, or does that not matter when taking T4?

SeasideSusie profile image
SeasideSusieAdministrator in reply to Grundywhiffs01

It's possible. I can't say for certain as we probably all react differently.

in reply to SeasideSusie

Hi Seaside Susie......I don't know whether this is of any help or not as my results are not currently optimal.

However, when I asked my Endo for extra levo he said no,as it would lower my T3,which is seemingly what is being asked for here by Grundywhiffs01 ?

( I have been given extra T3 .......but that's a different story.)

Grundywhiffs01 profile image
Grundywhiffs01 in reply to

More levo ( T4) will increase T3 and lower TSH.

in reply to Grundywhiffs01

Surely that isn't so if you have conversion problems?...... Am I right in thinking that if we only had to increase our T4 ,we wouldn't have needed T3 in the first place?

SeasideSusie profile image
SeasideSusieAdministrator in reply to

It depends how much natural conversion we have. I have poor conversion and take T3 with my Levo. I needed my FT4 to be way over range - as much as 165% of range - to give me a FT3 result half way through range.When I was adjusting my doses to find what was right for me, I found when I adjusted my Levo it did make a difference to my FT3, so I must still have some conversion, but not enough for me to do well enough without the addition of T3.

in reply to SeasideSusie

That's interesting SeasideSusie.......You've had quite a journey☹️

I am struggling at the moment to get my FT4 and FT3 into the upper half of range.

It is a difficult situation with getting extra T3 and thus I have phoned a pharmacy on the TUK list about purchasing Armour Thyroid.They can supply if I get a prescription,so I will approach my GP. My Endo can't prescribe it but will monitor me if I source it myself..........All best wishes to you.

Grundywhiffs01 profile image
Grundywhiffs01 in reply to

I was talking in general terms. I think you got the doctors message mixed up, and im pretty sure increasing T4 won't reduce T3, it may not get higher, but he/she probably said it will reduce TSH

in reply to Grundywhiffs01

I have full confidence in what my Endo said to me and will have a list of questions when I see him in May.

However, I have also wondered how much our levels rise during the day after a blood test,not having taken meds beforehand.

My T4/T3 results are always just under halfway and my TSH below 1,so need further adjustments too.

All the best with finalising your dosage .

When you are taking T3 then the only accurate reading is the FT3 which, as you say is near to the top of the range so I would split the dose the day before the test and set what that does to your readings. I'm assuming that before you added T3 then you were getting a high FT4 result and a low FT3 result? I used to get that but I addressed the conversion issue first by getting VitD, B12, folate and ferritin optimal as this helps conversion and it took time to get my levels optimal but it reversed it. Once you add in T3 you can't tell whether conversion is taking place properly as you only have one accurate reading-T3 so can no longer compare it with your FT4 reading as that can fall in its range.

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