Thyroid UK
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T3 and ferritin

I am about to make an appointment to ask the endocrinologist to give me a trial of T3 with T4. I am currently on T4 only. I have just discovered that my ferritin levels have taken a dive again. (April 2016 ferritin was 14. June 2016 ferritin was 85.) I have read somewhere that T3 should not be trailed while ferritin is low. I can't remember where I read this. Can anyone verify whether this true and give any sources of information about it? I would be grateful for any thoughts people have.

My lab results are:

free T4 15.9 pmol/L (9.0-22.7)

TSH 3.4 (0.35-5.5)

free T3 3.4 pmol/L (3.5-6.5)

ferritin 27 (10-291 ug/L)

7 Replies

I don't know about not trialling T3 when Ferritin is low, but no thyroid hormone (our own or replacement) will work properly unless Ferritin is at least 70, and half way through the range is the recommended level.

Considering the aim of a Hypo patient is for TSH to be 1 or below, and the free Ts at the upper end of their ranges, you are grossly undermedicated anyway. What dose of Levo are you taking?

Have you had B12, Folate and Vit D tested also?


Hi SeasideSusie, thank you for your reply. My dose of T4 is 50mcg then 75mcg on alternating days.

When I got my ferritin up to 85 in the summer my T4 went up to 18 and my TSH went down to 1.81. From October I started to feel more and more tired. My ferritin was going down again.

I should have vit D, B12 and folate retested. Thanks for mentioning it. They were good last time I had themdone but that was a few months ago. It's amazing how quickly they can change.

I'll see if I can find where I saw T3 and ferritin mentioned. It was something to do with having a bad reaction to T3 if your ferritin is low.

I would really like to try T3 because I am never totally symptom free even when my ferritin is good.


Low ferritin can give a lot of "thyroid" symptoms such as hair loss, tiredness and muscle aches. Have you been taking iron supplements to improve the ferritin levels? If you are unable to achieve a decent level then you need to ask your Dr why. A cause of low ferritin can be a gut absorption problem such as Coeliac. Coeliac is an autoimmune disease and it can be typical for people with thyroid issues to have more than one autoimmune issue. Not everyone who has Coeliac has bad bowel issues - sometimes low vitamins/minerals are the only noticeable symptoms (thats what happened to me)


Hi judburke, thanks for your reply. I do have digestive issues but came back negative for coeliac. I think I have food sensitivities. I have been working on trying to identify them and now have very few digestive problems but there are foods I can't eat such as onions, vinegar, lemon and cheese. It could be that I have been undermedicated for many years, as I suspect and low stomach acid has not allowed my body to absorb minerals.

I am taking florafix twice a day to try and bring my iron levels up. I've been taking it for two weeks now. I'm also eating a small steak with half a gram of vit c for breakfast. Still very tired but I noticed that dizziness is reducing. It was constant, now only in the evening and not every evening. I also supplement magnesium and zinc, interestingly, all metals. I don't know why the metals in paticular are a problem.

1 like

It does sound like you have gut/food issues. Good luck getting your ferritin up. I only start to feel good when Ferritin is up to 70/80 and then it takes a few weeks later for the symptoms to improve e.g. Hair loss.

What I would say about Coeliac is that it can develop at any time. I had tests years ago that were negative but recent test later proved positive. So don't discount it completely for the future.

As I understand it for any thyroid medication to work properly and to support what function you do have then you need Ferritin, B12 and D3 to be at optimal levels i.e. not just in range. Have a look at this website that explains optimal values and what is needed for thyroid function. It really makes a difference to overall health to get these up. Also I think low B12 can contribute to gut issues

Good luck getting the ferritin up :)

1 like

I meant floradix not florafix


Have you had your antibodies checked during bloods?


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