Thyroid UK

T3 and Palps

I've recently had to switch from T3/T4 to T3 alone. Trying to raise T4 resulted in an increase of hypo symptoms.

On 25mcg of T4 and 37.5mcg T3 my bloods were:

TSH 0.08 (0.3 - 6.5) FT4: 8.4 (9 - 2.5) FT3: 4.7 (3.5 - 6.5)

Prior to this I was on 75mcg T4 and 20mcg T3

TSH: 0.01 (0.27 - 4.20) FT4: 17.9 (12.00 - 22.00) FT3: 5.2 (4.00 - 6.80)

Every time I try to increase the T3 I get slow hard palps. If I reduce the T3 then the palps subside. If I stay on the increase the palps get worse daily.

I'm not low in iron and vits etc. are good or I supplement. Cortisol levels are good.

I have to come off of T4 as I think it has built up in my body and is not being utilised. Many hypo symptoms occurring.

I have given blood levels but does not really show what is going on in my body. Bloods look good with T4 but I am very hypo.

Any thoughts?

5 Replies


How long have you been taking T3 only and what dose?


I switched to NDT recently to see if I could tolerate this but I'm having the same problem.

I'm currently taking 18.75 mcg T3 and 1.75 grains of NDT and have been on this for a week. In the past I could raise T3 without any problem.

I've stopped medication since yesterday p.m.

I'm also getting a racing heart in the night when I wake to use the loo.


Have to say I increased NDT gradually beginning with 1 grain for 2 weeks and increased another half grain whilst reducing the T3 I was on but it seemed to have backfired.



I think you are probably over medicated on 1.5 grains NDT + 18.75mcg T3.

75mcg T4 + 20mcg T3 = 135mcg T4

25mcg T4 + 37.5mcg T3 = 137.5 T4

1.5 grains NDT + 18.75mcg T3 = 170mcg T4

Try reducing T3 to 6.25mcg as there is already 13.5 mcg T3 in 1.5 grains NDT.


Much appreciated Clutter.

It makes sense now - thought I was going to have a coronary. I'm hopeless at figures especially NDT. Many thanks


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