Is TSH level of 0.01 too low for uat? - Thyroid UK

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Is TSH level of 0.01 too low for uat?


I'm finally feeling more like 'old me' after 5 years uat and have lost the weight that I put on. My tsh is 0.01 and T4 is 33.5. I take 150 mcg thyroxine which is so much better than 125, six months ago when I was tired etc. Is this dose and levels potentially dangerous for me?

I have tried halving a 25 mcg tablet before now!!

13 Replies

It has been said so many thousands of times on here that the TSH is irrelevant. Once you are on thyroid hormone replacement, it is meaningless. So, forget that!

Do you have a range for that T4? It looks like it might be a bit high. However, having said that, what is important is to know your Ft3. That is the one that is going to tell you your thyroid status. T4 is just a storage hormone, it doesn't do anything. T3 is the active one.

But having said all that, how you feel has to be the clincher. If you are feeling good, with no hyper symptoms, then fine. That's what counts. 150 isn't a very high dose, anyway. It has suppressed your TSH, but then it would, wouldn't it. That's the point of the TSH. lol

See if you can get your FT3 tested and find the range for the T4 and we'll get a clearer picture.

Hugs, Grey

Trewoof in reply to greygoose

Thanks Grey! I'm not hyper at all and my FT3 is 6.6 and within range. FT4 rang is 9 to 28 and I'm 33.5?


If it were only the TSH being very low, then there might be no reason to say your dose is too high. However, and FT4 of 33.5 sounds way above any of the typical UK T4 lab ranges, so it would not be a surprise to me if your GP wanted you to reduce your dose. That said, you haven't quoted the actual T4 lab range for your test.

Presumably you don't have an FT3 result to accompany the TSH and FT4? An FT3 result would give a clearer picture of things.

Trewoof in reply to RedApple

Thanks for replying, Sorry should have said T3 is 6.6 which is within range 0.0 - 7.7??

Trewoof in reply to Trewoof

. . And lab range for T4 is 9.0 to 28.0


Did you take your tablets in the hours before that blood test?

The FT4 level at 33.5 would be way out of range on any reference range. Are you getting any symptoms of being over-dosed?

If you wish to take, say, 137, then you could try 125 one day, 150 the next. Many people are happy on a regime like that. Or some pattern like 125, 125, 150 - or 125-150-150.

You know, some people find they need less is warmer weather.


Trewoof in reply to helvella

I did take my tablets before blood test which I have never done before!?

I think I will take 125 and 150 alternate days and see how it is after Summer.

Thanks Rod

helvellaAdministrator in reply to Trewoof

... and which you will never do again! :-)

Although 33.5 is very high, the combination of a reference range with an unusually high top end and taking a tablet relatively shortly before the test might suggest an explanation.

If you want your TSH to show its highest value, get the blood drawn as early as possible in the day. E.g. 08:00.


amandabaker in reply to helvella

Can you help me please? My 19 year old daughter has chronic hypothyroid symptoms. She was put on Levothyroxine (50mgm) and Liothyronine - at my insistence -(10mcg) 6 weeks ago. Her initial blood tests showed TSH 2.73, FT4 13.6 and FT3 4.82. Her endo agreed to put her on medication for a short time to rest and reset her system - we think she has adrenal fatigue. She started immediately to feel better. After the first month her blood tests showed TSH 0.06, T4 15 and T3 4.84. I was surprised and disappointed her T4 and T3 hadn't improved. Since then she has got steadily worse again, so that now she is just as exhausted as she was prior to going on the medication. Can you tell me whether it is the Levo or the Lio that I need to see whether we can increase? Does the Lio effect the T4 and T3. I can see that her TSH should be low enough now. Initially her endo had been talking about a ratio of Levo to Lio of !:5, but she is on 1:10, so I assume it is Lio we need to try and up? Many thanks for your help.

Hidden in reply to amandabaker

amanda, I suggest you ask this as a new question as this will be missed on the end here. I don't know enough to help you, but if you ask as a new question, it will be seen by many more.

best wishes


amandabaker in reply to Hidden

Thanks Liza. I am new to blogging so thanks for the advise! I have done it. regards Amanda

Hidden in reply to amandabaker

Hi Amanda - that's great! I'll be interested in seeing the answers and I hope you get some help for your daughter... good luck xx

Heloise in reply to amandabaker

You may find some answers here:

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