Log in
Thyroid UK
91,762 members106,054 posts

Low free T3


Please could I get some advice?

I got my thyroid function test results today and they were TSH 1.99, free T4 15.7 and free T3 1.4. I am on a dose of 150mcg a day.

I am normally pretty tired, I can loose weight easily and I normally have to take 1-2 senakot daily to deal with constipation.

My doctor checked my haemoglobin level and that was 137. So not anaemic.

I think my free T3 level is way too low and I'm worried that I'm not covering T4 to T3.

Does anyone have any ideas what might be going on?

Thanks in advance.

19 Replies

Auchlyne What are the reference ranges for those results?


Looking ranges on internet:

TSH 0.4 ~ 4.0

FT4 9.0 ~ 25.0

FT3 3.5 ~ 7.8


Auchlyne Ranges from the internet aren't any good. Ranges vary from lab to lab so it's essential to have the range from the lab that did your test.

To know if you are converting well enough or not, it's necessary to know where in their ranges the FT4 and FT3 lie.

1 like

Ok. Thanks. I'll speak to doctors on Monday


Your ranges should be written right beside your results, blood results are never given without ranges.


Why why why do these endos not learn half of what we do

Your t3 is way way too low and precisely why your still constipated and no doubt have a myriad of hypo symptoms

Has your doctor bothered to test vital




Vit d3

Because all of them must be at least halfway in their ranges for the conversion of t4 into t3 to occur

Hypothyroid trashes a host of vitamins especially vit b and vit c

Testing heamaglobin is simply not enough its stored iron /ferritin that matters

Also ar you taking any other meds as things like PPIs can block absorption

Ensure you take at leat 2000 mg vitamin C every day in split doses

1 like

Not taking any other meds. Started taking a multi vit and vit d. But these were not tested.


At best, a multi-vit will do no good. At worst, it could do harm. It's a waste of time and money for many reasons. Too much vit D can be toxic. On the other hand, if you haven't been tested, you may not be taking enough. Best to get everything tested and just take what you need, in quantities you need, and not play Russian roulet with multi-vits. :)

Having said that, there are some things you can take without getting tested, because excess is excreted. Magnesium is one. Getting tested is pointless, because it will always be in-range, due to the way the body handles magnesium. But, that doesn't mean you're not deficient, most people are, because soils are depleted. And, if you get magnesium citrate, it will help with your constipation.

Vit C also, you can take up to 5000 mg a day, up to stomach tolerance. And that will also help with constipation. And, you could try selenium, to see if it will lower antibodies.

1 like

I forgot to add at the beginning that I was diagnosed with Hashimoto's 8 years ago, 6 months after the birth of my first child.


So, are you gluten-free? You really need your TSH at zero when you have Hashi's. So, yours is much too high. You need an increase in dose.


I had that tested and results came back negative. But I'm beginning to feel that i should listen to my body, treat the symptoms not the computer read outs!


You just said you were diagnosed with Hashi's 8 years ago. It doesn't go away. If you had it then, you have it now.


I understand that. Apologise if I gave the impression is cured it! Just trying to understand how I can lessen symptoms.


No, you didn't give the impression you've cured it, you just said you didn't have it, after having said in the post above that you had. I'm confused.

But, as I said above, gluten-free diet, selenium and TSH at zero to lower antibodies, and the symptoms caused by them. To lessen symptoms caused by low T3, you need to optimise your T3.

Selenium will also help with conversion, so a good thing to take.


Ah. I see where the confusion is. I was tested for gluten sensitivity / intolerance.


Another reason to stay clear of multivitamins is that some can't be taken together so will be inaffective.


As you have Hashimotos you really need to avoid any extra iodine- it can make Hashimotos worse - many multivitamins have iodine in

Also food intolerances are common (usually gluten, sometimes dairy, soya and/or nightshades - tomato, peppers, potatoes) and Hashimotos causes (or is caused by) poor gut health. Very common to have leaky gut, leading to low nutrients - get vitamin D, folate, ferritin & B 12 checked.

Many of us with Hashimotos find gluten free diet can really help reduce antibodies

Selenium supplements may help improve conversion of T4 to T3


its still vital that




vit d3

are all tested and you get results

stay off those vits for now too as we need to know exactly what needs sorting and then we can fathom symptoms


Just got the values and ranges from the doctors

TSH 1.99 (0.35~5.5)

Free T4 15.7 (9~24)

Total T3 1.4 (0.9~2.8)

So within all the ranges, but all have symptoms!


You may also like...