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Thyroid UK
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What is best to take for low T3?

After paying for many private tests, etc to rule things in or out, I am gradually getting to the bottom of the problem of my thyroid like symptoms and my Hashimotos.

After a Urine Tyroid test which showed up lowish T3 levels,  (and I may also have possible insufficient 5 deiodinase conversion enzymes,T4 to T4), and further advice and consultation it appears I need to supplement T3 in the short or longer term.

I am waiting for a further private consultation this week, but my question is what is best to help with my T3 issues. NDT, levothyroxine, T3?

I visited a new GP as the other one said there was nothing she could do for me, she has said she will help if she can, which sounded a bit ominous, but I am not sure if she will prescribe NDT for me, or it could be levothyroxine?  Which is best, and if I have to buy privately, where can I buy from a bona fide supplier?

I live in Bristol and it may be possible that other members might know of a GP/Doctor who will prescribe what I need.

My part recovery and feeling better is also very much down to the advice and help I have received on this forum - thank you.

9 Replies

That rather depends. I'm sure folk here would be happy to take a look at your blood results if you'd like to post them.  Most people do just fine on levothyroxine - it's usually only people who can't get diagnosed or who are under treated who find this forum.

What's your ferritin result? If ferritin is low, the first thing to do is get that up, so that your body is able to convert the T4 your thyroid is producing into T3, the active form of the hormone.

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Thanks for the prompt reply. I have seen Dr Peatfield and he has interpreted by bloods and urine tests. My ferritin. is ok ..I was below range for B12 iron etc..I am now supplementing these after advice from the forum. I have a follow up call with Dr Peatfield to ask some questions re this, but as he is now unable to prescribe for my T3 I thought I would seek the advice of those qualified by experience which option might be best if I go to my GP or have to buy privately. Best H


You're not giving us much to go on. 🙂 

GPs often won't act until TSH is over 5 - and some are convinced there's no need to treat until it's over 10. Many GPs have no idea how to interpret FT3 and FT4 results, assuming "in normal range" is fine, when it isn't. And I'd suspect most GPs will roll their eyes at thyroid urine tests - because they're just not done on the NHS and they don't know if they're valid or not.

If you have positive antibodies and a clued up doctor (sadly rare) you might get diagnosed with hypothyroidism with a TSH around 5. Anything below that and you'll have a fight on your hands. Many of us here know that fight painfully well...


Sorry..I have in the past posted all my results etc on the forum and received very good help and advice to take things further. At the stage now that I have identified what needs to be done i e. my T3 needs supplementing. My new GP was very open and interested in the results of my Genova Thyroid urine, cortisol and complete digestive stool test. I have very high thyroid antibodies 1000+,  but as you rightly point out most GPs wont do anything about this. My first GP and Endo would not even acknowledge the term Hashimotos, even though this is identified on the NHS website stating that Levot can be prescribed.

My urine test showed a result of 667 when the reference range is 800 to 2,500 pmol 24h. 

The thyroid blood test showed a

 TSH of 1.070 uIU/ml reference range 0.1 to 5.00

Free T3 4.8 pmol/L reference range 3.1 to 6.8

My CDSA showed low Lactobacillus and Bifidobacterium,  which I am now supplementing for.

Going back to the GP and if she will prescribe I just want to be informed which option is best.  If I have to go it alone then again I would welcome advice on what and where to buy is best On the advice of the forum I did not jump into self prescribing until I have ruled most things out i.e adrenals etc. 

Thank H


Thanks - apologies, I did look back through your older posts but couldn't see anything recent (most recent was 7m ago) and assumed your results were newer than that.

I think you're going to struggle to find a doctor who will prescribe on the basis of those results, so if you want to pursue T3 it'll be via self-medicating, most likely. Speaking from experience, it's not ideal, and it's worth knowing that it's not a question of taking a small amount of T3 to "top you up" - it doesn't work that way. You effectively override the feedback loop to your pituitary gland when you take synthetic hormones or NDT, so that your own thyroid stops producing hormone altogether. You then have to take sufficient hormones to fully replace your thyroid function. You may decide that's what you want to do - in which case, I'm sure members here would be willing to PM you with details of where they source their thyroid hormones without prescription.

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Thanks for taking the time to look back at my results. The advice youbhave givennis very helpful and helps me to understand it a bit more.  The urine tyroid test and saliva adrenal cortisol test is more tecent as is the comprehensive digestive analysis. Just trying to rule everything out.

Dr Peatfoeld thinks my osetrogen might be dominante and this can cause issues with conversion of T3 having my female hormones tested soon.

Its complicated isnt it? But cant go on like this.  I don't have much confidence that the new GP will do anything, she doesn't seem to understand it much.To be fair she has been open to what Dr Peatfield has said.

Best H



What is your T4 result ? 

If you are going to be prescribed Levo on the NHS, then you may (if terribly lucky & see a sympathetic endo) get T3 prescribed as well in view of your conversion problem or  members tend to supplement their own.

If you are on your own in this, you may want to consider NDT which is a more natural complete medication. However, it depends on adrenals health as I read NDT is less likely to be tolerated if cortisol levels are insufficient so making synthetic meds a more favourable choice..

Whatever meds you take, it is vital to have optimal iron and nutrients levels which thyroid hormone synthesis relies on. If you post any recent test results members will comment.


Disclaimer: I am not a medical professional and this information is not intended to be a substitute for medical guidance from your own doctor. Please check with your personal physician before applying any of these suggestions.



Hello Flower007

Dr Peatfield thinks my oestrogen might be causing some issues and having T3 will help whilst this is sorted out..I am having my female hormones tested by my GP. as I am not producibg enough T3. It could also be issues with insufficient 5 deiodinase  conversion.

Sadly the private  endo I paid to see just quoted statistis about how many people with high antibodies feel unwell compared to those who have no issues.

My bllod test  free T4 was 16.89pmol/1 ref range 12 to 22

My urine test was 1340 pmol/24h ref range 550 to 3160.

My adrenal stress test (saliva)  24 showed my cortisol levels were high all day and evening.. My DHEA was within range. Dr Peatfield felt that I did not have adrenal issues.

I had read that NDT was best but some people's seem to have issues, possibly due to under or over medicating. 

I am supplementing for all the vits and nutrients. .this has eased some issues but others persist or new ones come along. We have a local organic shop with excellent trained staff disoensing supplements and they know more about the thyroid than my GP.

I have tried excluding gluten but it made no difference. I have a very low sugar diet toio.

If I have to go it alone I want to buy from a good supplier, and try and start on.the best thyroid med I can.

Thanks again. H



The endocrine system works in synergy and there is a distinct intricate connection between our thyroid, adrenal glands, and sex hormones.

If you have seen Dr P he will have explained the importance of adrenal gland health. When ACTH (pituitary gland) can't get the (poor over worked) adrenals to produce adequate cortisol, oestrogen is secreted instead. Elevated oestrogen can bind with thyroid hormone carriers stopping hormone from reaching peripheral receptors. It also binds to any last bit of available cortisol (cortisol-binding globulin) and prevents new from being released from the adrenal cortex.

Oestrogen should be balanced with progesterone but this declines  with age, health issues, etc.  Many find the transdermal creams are enough to rebalance but both my O & P were very low so I now supplement both. You need to wait for your sex hormones results to be able to supplement appropriately.

 Your results given to jazzw above were:

TSH of 1.070 uIU/ml reference range 0.1 to 5.00                                   

Free T3 4.8 pmol/L reference range 3.1 to 6.8

Your initial post advises of a high thyroid antibody count indicating Hashimotos so eating gluten free will help reduce the immune responses in the body. These recent results are not typical of unmedicated (thyroid hormone) Hashimotos as this would produce a higher TSH, demanding more hormone secretion from a flagging thyroid gland. Your T3 is just within range but do you know your T4 result ?

Did Dr P not mention anything about a possible pituitary issue ? ? ..

Supplementing T3 or any thyroid hormone will not address a sex hormone issue alone if there are other underlying causes. A conversion issue is common (I have one myself) but until further results are received, it is difficult to know what complexities are involved here.

It is good you are addressing gut issues. Ensure you don't have candida, etc as low thyroid hormone reduces stomach acid which allows the gut dysbiosis to occur and so a vulnerability to bacterial/fungal infections..

Have your iron & nutrients been been tested lately as you were deficient last year ?. Have you been supplementing to address these deficiencies ? ? ..

Be pleased you are on the road to wellness even though it can feel like  a long one. Have you read Dr P's book 'Your Thyroid & How To Keep It healthy' ? Education will allow you to make informed decisions as our medical profession aren't always too well informed themselves ! ! ..


Disclaimer: I am not a medical professional and this information is not intended to be a substitute for medical guidance from your own doctor. Please check with your personal physician before applying any of these suggestions.


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