Conversion problems :(: My endo strongly insisted... - Thyroid UK

Thyroid UK
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Conversion problems :(


My endo strongly insisted that I should not take T3 or even increase T4. We almost had an argument and at the end he was really angry. So we reached a compromise I increased my T4 from 75mcg to 100mcg and these are the results.

TSH 0.02 ( 0.30-4.20)

FT4 26.5 ( 12.00-22.00)

FT3 4.4 (3.10-6.80)

previously on 75mcg of T4 the results were: ( same range)

TSH 0.348

FT4 18.7

FT3 3.65

All in all I seem to be better with 100mcg ( skin less dry and a bit more energy).

I wish I could find a way to increase the conversion FT4 to FT3 . I have the DIO1 - Thyroid Hormone Activation poliformism AA result:

The 'A' result is not associated with increased DIO1 gene

function and is therefore not associated with high conversion

of FT4 to T3, or of reduced circulating rT3 levels. Ensure

adequate iodine and selenium intake to support this pathway

optimally. Likely to have low DIO1 activity and therefore decreased

clearance of rT3 from circulation, and low conversion of T4 to

T3. Ensure adequate intake of iodine and selenium to support

this pathway.

DIO2 - Thyroid Hormone Activation


The 'C' result has been associated with anxiety and

depression in many taking thyroxine (T4) hormone

replacement therapy for hypothyroidism. This can be

overcome with combined T4/T3 therapy. Also linked to

possible increased risk of oestoarthritis. Ensure adequate

nutrition for bone health, such as calcium, and vitamin D

(which may also help with low mood).


The 'C' result is associated with normal (not increased) DIO2

activity and is not associated with any particular impact on

thyroid hormone ratio. Adequate levels of iodine and

selenium are required for optimal functioning of this gene.

When I take T3, Ft3 goes high out of the range...

I don't know if anyone has any suggestion...thank you. At the moment I feel like I have no more clues...

12 Replies

Are you having your blood tests after taking your meds?

in reply to Aurealis

No, I take my meds before bed and had the test the day after. I know that especially if you take T3 and then have the blood tests soon after it shows very high.

in reply to Clara62

Some say to leave 12 hours after meds but possibly even longer is needed. The important thing is to take the dose you feel well on even if you have to do things slightly different to get results in range. Consistency is the thing so that you can check if levels are creeping up or down.

in reply to Aurealis

Thank you :)

in reply to Clara62

You should leave a gap of 24 hours between your last dose of levo and your blood draw. :)

in reply to greygoose

Will certainly do it next time. 🙏



Well you obviously have poor conversion and a donkey for an endo. Why bother with the endo? He's doing you no favours and will keep you ill.

I wish I could find a way to increase the conversion FT4 to FT3

Have you tested

Vit D




These all need to be optimal for thyroid hormone to work and help conversion.

Once you have optimal nutrient levels which are

Vit D - 100-150nmol/L according to the Vit D Council/Vit D Society

B12 - top of range for Total B12, at least over 70 for Active B12

Folate - at least half way through range

Ferritin - at least 70 for thyroid hormone to work

if your conversion is still poor then in your situation I would just continue to collect your prescription for Levo from your GP, lower dose of levo by 25mcg and a couple of weeks later add in 1/4 of a tablet of T3 (if self sourced it will be a 25mcg tablet so you'd be adding 6.25mcg T3). Wait 2 weeks, add in a second 1/4 of a tablet of T3 so total will be 12.5mcg T3 and 75mcg Levo. Wait 6 weeks, do a private test for TSH, FT4 and FT3 with Medichecks or Blue Horizon, see how you feel and what the results are then adjust further if necessary.

Sometimes the only options are to either help ourselves or let our doctors keep us ill. I chose the former.

PS - for blood tests, last dose of Levo should be 24 hours before blood draw, last dose of T3 should be 8-12 hours before blood draw, adjust timing of doses the day before if necessary. Leave off B Complex/Biotin for 7 days before testing.

Thank you so much SeasideSusie. Good information.

Vit D . 102 ( (50-200)

B12 181 ( 25.1 - 165.0)

FERRITIN ( most recent one is 55, two years ago was 66). So the ferritin is too low.

I used to be in a compounded med t4/t3 what happens is that the TSH is suppressed ( I know it's normal) the FT4 is suppressed too and FT3 sometimes was good in range , upper part, other times way off the range like 10. And I used a very low amount like 5 or 10mcg

I wonder what is the best way to increase ferritin.

in reply to Clara62

I wonder what is the best way to increase ferritin.

You can help raise your level by eating liver regularly, maximum 200g per week due to it's high Vit A content, also liver pate, black pudding, and including lots of iron rich foods in your diet

Thank you 🙏

Y our conversion FT4/FT3 ratio is 6. That proves, togeher with a lowish FT3 that you are a poor converter. Likely that direct T3 by mouth is going to help.

in reply to diogenes

Thank you diogenes, yes, I definitely am a poor converter. I need to be very careful with supplementing T3 though, even the tiniest amount send it way off the range, like 10...

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