Thyroid UK
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T4 to T3

Hi, I'm currently taking 125mcg of levo and my recent blood tests say I'm within the range I need to be yet I am in constant pain with my joints and muscles. I also have problems with constipation and have to take 25g of ground flaxseed a day with masses of water otherwise everything stops! I'm constantly tired yet don't sleep well at night although some of that is down to hot flushes as I'm 52 and 3 years post hysterectomy. I have incredibly dry and itchy skin and I can't lose weight without going below 600 calories a day. I have asked my GP to try changing to T3 but she said she can't prescribe it. How can I source T3 myself and if I can get it what would be an equivalent dose and how should I make the transition please

13 Replies

Welcome to our forum,

First I would ask your GP to do a full thyroid function test. Some will only do the basic. We can get a full thyroid panel from one of our recommended labs.

Many doctors make the same mistake by telling the patient they are 'within range' so don't prescribe an increase in their medication.

If we are diagnosed with hypothyroidism - in range isn't where we want to be. TSH should be below 1 ideally according to the Ex President of the British Thyroid Association. The Free T4 and Free T3 should be towards the upper part of the range but these are rarely tested.

Can you get a print-out of your latest blood test results that you can post for comments and make a new question if you don't have them today.

Doctors know little about how to improve the patients' symptoms.

Did you have a blood test at the very earliest possible, fasting (you can drink water) and allow a gap of 24 hours between your last dose and the test and take afterwards?

If not, ask for a new blood test including B12, Vit D, iron, ferritin and folate.

1 like

Thank you, I have contacted the surgery just now and they are going to have the print outs ready for me to collect in the morning. Apparently, the doctor does want to see me about one of the results and I have an appointment for May 4th. I wasn't a fasting blood test or early in the day as far as I can remember. I post the results tomorrow


Always make sure from now on that a fasting, early as possible test is taken as that can make the difference between getting an increase in hormones or not.


shaws , I agree with you a million percent . Dr only care about TSH . They don't care about patients "SYMPTOMS" . There in lies the very big PROBLEB of the thyroid Dr's.

We as thyroid patients have to work very hard to change the way our care is handled .


When first diagnosed and if it's taken a long time, we are very relieved indeed we have a name to our problem. After a while on levo when still be suffering or even getting many more symptoms, you don't at first realise it is the prescription you've been given. Slowly but surely because we are able to use the internet we can find out more and are astonished that there's more to it than levothyroxine.

Dr Peatfield tried. Dr Skinner tried and I think because he was a Virologist he was ignored completely and he did say the situation many were in was 'parlous'. They ignored him and refused, one by one, his invitation to discuss the matter.


heloli64 Before you consider going down the T3 route (it is in short supply at the moment so there are delays) you really need to put your whole house in order and have a firm foundation for any thyroid hormone to work.

First of all, what are your latest thyroid test results? If you post them, with their reference ranges (important), members can comment.

Then there are vitamins and minerals. Have they been tested? Are they at optimal levels (not just 'in range').

So, we need to see




Thyroid Peroxidase antibodies

Thyroglobulin antibodies

Vit D




If your GP won't do them then a private private fingerprick test to do at home can cover them all

If you've already got any of these results, post them for comment.


Thank you, I'm not sure what she tested for in total but I'm picking up the print outs tomorrow and I'll post them. In the mean time I think I'll do the finger prick and pay privately as I doubt she'll repeat them as the local hospital refuse to test more than once a year unless a result is abnormal. Thanks for info.


I would add Total T4 . It's a big marker if the FT4 is mid rang Total T4 can be below . And patients still don't feel well .


I have a underactive thyroid, been suffering from some of the things you mention, been very lucky and my doctor asked for a full blood test, which included checking everything which seasideSusie recommended, it looks as if I have a vitamin D problem, she has asked me to make a telephone appointment to discuss it. So worth getting your vitamins checked. Hope this helps, best of luck.


Many thanks. I'll make sure it's been check or gets checked


I would agree with everything that has been said here. You must also find out if you are converting t4 to ft3 properly. If not I would recommend checking your selenium levels. I had a selenium defficiency. I now take 100 -200mcgs a day and my body is very efficient at converting to ft3, my problem is that I dont have enough t4 to convert. I would do that before going down the t3 route xx


Many thanks, how do you know if your converting or not, does that show up in the blood tests


you can tell between the ratio of ft4 to ft3. Should be at least 4:1. You must have a good level of ft4 to convert in the first place. So as seeside susie said earlier if you have these tests done they will tell a lot and provide the answers hopefully xx


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