Underactive to over active thyroid: Finally got... - Thyroid UK

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Underactive to over active thyroid

Finally got my blood test results and I was just looking for some advice/guidance or if you can shed a bit of light on them! So I have underactive thyroid and I'm currently taking 50mcg. I am 22 years of age.

Looking at my results It states biochemical test normal? no.?

Also, serum free t4 level 34.6. Serum Tsh level <0.01. Serum free t3 level 9.9.

Also, thyroid function test abnormal. So they have now classed me as over active, however if they stop my medication I will return to be underactive. What do you think? I've also been trying to conceive for 4 years and had 3 miscarriages because of my abnormal thyroid. It's really hard to stay strong. Any help would really be appreciated x

13 Replies

Poor you. I'm sorry to hear about your miscarriages and I know what you mean when you say it's hard to stay strong.. Do you have the ranges to help put the test results in context?


So it's says..

Serum free t4 level 34.6 pmol/L (10.30 - 24.50 pmol/L)

Serum Tsh level <0.01 mIU/L (0.40 - 5.50 mIU/L)

Serum free t3 level 9.9 pmol/L (3.50 - 6.50 pmol/L)

Thank you for your reply :) x


Do you have hyper symptoms? Do you feel better on this dose of levo? When did you take your last dose of t4 before the test? Your t3 is a bit high and I imagine they'll want that to go down a bit but I think if you're feeling well it can be high in the range. They just don't want you to have problems down the road because of sustained high t3, but they should take your feelings of well-being into account too. :-)


I actually feel ok.. When underactive I feel so tired and drained and when I was over active previously I had the worse headaches ever. But this time around I don't seem to have any symptoms. I still have that foggy in a daze feeling, and being forgetful but I'm guessing that just thyroid in general lol x


Hmm, the t3 is quite high and it might be worth seeing if you can slowly reduce a bit (though that is contentious and others may say if you feel well you should stay where you are). But the doctor must take into consideration that you are feeling pretty well. (Feeling fuzzy could be a hyper symptom so you could feel even better on a tiny bit less levo.)

I felt well when I was a little over the range (not as high as your results). But of course some people find they go up and down anyway so your next test could be fine. Ugh, this whole thyroid thing is impossible.


How long had you been taking 50mg before you had the blood test?

I upped my dose and my results looked hyper but i retested a few months later on the same dose and my blood tests fell back to normal.


I have been on 50mcg for about 5-6 months without interruption now. At one stage I was on 50mcg and then 75mcg every other day which caused my thyroid to become over. Since going to 50mcg it went stable/normal and now all of a sudden I'm over again lol x


You could always try 24mcg every three days. You might even feel better on a little less, as long as they agree to test you again before too long and raise your levo if you start to feel ill.

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Might be worth talking to your doctor and trying a lower dose like 25mcg and see what effect that has.


Did you take levo before your blood tests, as this can have an affect on the results? Your dose of 50mcg is usually a starting dose but if you feel fine, that's the dose for you.

My TSH is the same as yours and I am well. If you feel well, it is a mistake to mess about with the doses unless you have clinical symptoms, either of over-stimulation or hypo.

This is a link but some of the links within may not work as the site is archived.



I agree with Sandy12. If no hyper symptoms, keep dose the same and wait for next test. Check blood pressure regularly (pressure tester is £15 from chemist). Make sure you don't take tablets close to the blood test. I usually get a test at 5pm and have not taken any T3 since 12.00 midday. My TSH is under 0.1 for me to feel well.


Hi! it is possible to go from being under active to over active & nothing to do with your medication as such. I first became over active in 2004 treated with Carbo then after a couple of months went back to normal so stopped the Carbo. I was okay for 4 years (thyroid normal) on no medication then I became underactive in 2008 took Erfa & T3 which I purchased abroad, I was Hypo for nearly 4 years then in late 2011 I was diagnosed with graves disease & was referred to a consultant who tried everything to control my thyroid I was on a very high dose of Carbo, they tried block & replace all to no avail & they decided the only way forward was to have a thyroidectomy. My consultant said it was very unusual for someone to go from being Hypo to Hyper and in my case it depended on which receptors were picking up the signals. I was terrified of having the op & becoming Hypo once again with all that entailed & had a stroke the week before it was due so it was cancelled & in May 2013, I had my op & have not looked back since, my weight has remained stable at 8st 6lbs. I did stipulate before op that I would not take Levo as it did not work for me & that I would prefer Efra or something similar plus T3, he said he could not get the PCT to authorise the NDT but could prescribe Liothyronine (T3) he said to give levo another go plus the T3 which is working well for me, fingers crossed. I never really gave Levo a chance as when first dx with Hypo the doctors I used to be under put me on 50mcg of Levo & left me on the dose with no follow up blood tests, I was so ill & researched on the internet where I found a brilliant website that helped me & I started self medicating. I realised what poor treatment I had been receiving & changed doctors, I made the new doctors aware before I joined the practice that I was self medicating & they where okay with it whereas my old practice did not like it one bit & were quite nasty with me. I currently take 75mcg of Levothyroxine & 20mcg of Liothyronine (T3)

I hope this helps someone xx


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