Thyroid UK
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I Have Low T3 and recently suffered terrible leg pain before my leg collapsed. Could this be linked?

I have been tested for potential hypothyroidism with the following results:

TSH of 1.9 (normal range 0.3 - 4.7)

T4 of 15.6 (normal range 9.5 - 21.5)

T3 of 3.5 (normal range 3.5 - 6.5).

My endo has described this low T3 as "biochemically not meaning very much when accompanied by normal range FT4 and TSH". He suggested Selenium 200 mcg/d might help conversion from T4 to T3, but this does not seem to have made any noticeable difference.

For 4 to 6 weeks I took T3 (Liothyronine [3 - 16 mcg/d]) and found my total cholesterol dropped 2 points, evidence of blood in urine disappeared, pulse rate increased from mid-40's to mid-50's, lost 1 stone in weight and felt normal for the first time in years.

However, a few days ago I suddenly experienced terrible pain in my left leg which then collapsed and I suffered two broken wrists as a consequence of trying to save myself from falling. I am now very worried that this could happen again at any time and wondered if this could be anything to do with low T3?

Many thanks.

17 Replies

Sorry to hear that, I wish you a speedy recovery.

I haven’t heard of that happening before due to T3. But a GP once told me that low thyroid can cause anything as it affects every cell in your body but I don’t know.

Are you on Levo? I wonder if your dose needs to be higher to bring you into the part of the range where you feel well.

It will be interesting to see what responses you get. Good luck.


Hi, thanks for the reply. No I am not on Levo, the T3 was self prescribed. Kind regards


The pituitary responds to both fT3 and fT4. So if both are mid-interval or one high and one low you would expect a normal TSH, say around 2.0. In your case your fT4 is mid-interval but your fT3 is at the lower limit. We really would expect a much higher TSH in this case. So, your TSH is not responding as it should. This leads to lower overall hormone levels and hypothryoidism. Endocrinologists treat TSH, fT3 and fT4 as if they were indpendant and of course they are not.

His suggestion of selenium shows a lack of knowledge. Low selenium causes impaired deiodinase, in all tissues including the pituitary. Consequently fT3 will be comparatively low but TSH will also be high because the pituitary will be unable to convert T4 to T3.

It's not clear whether '3 - 16 mcg' means '3 to 16 mcg' or '3 times 16 mcg'. In any event it is very unlikely the L-T3 caused your leg problem, too much hormone tends to cause chronic problems. You are certainly hypothyroid with these blood tests.

Have they checked out your leg problem? Perhaps do an MRI of your spine as it could be a sciatic nerve problem.

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Hi Jimh111,

Many thanks for your reply. The 3-16 mcg should have said - 3mcg working up to 16 mcg, then slowly working back down to nought.

I do have spinal problems due to a car accident 25 years ago. I have had 2 MRI scans and there is a disc problem. The 'specialist' advised I don't take it further as I have managed the problem with exercise. At the moment I do not feel as though I have any problems with my back but will not rule out that being the problem.

I just seem to have so many symptoms no endo. seems willing to treat I just wondered if the leg collapse could be related.

I appreciate the time you have taken to reply, many thanks.


Forgot to say it helps to keep your magnesium levels up. Also supplement with high dose methylcobalamin (B12), even if you are not deficient as B12 helps avoid neuropatic pain.

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Essential to test vitamin D, folate, ferritin and B12

Low vitamins are extremely common when hypothyroid

Low vitamin D, (and low magnesium) can affect bones. Low vitamin D often causes bone pain

Calcium levels may be low if vitamin D is low. Calcium levels naturally increase as vitamin D improves.

Have you had both TPO and TG thyroid antibodies tested ?

For full Thyroid evaluation you need TSH, FT4, TT4, FT3 plus TPO and TG thyroid antibodies.

Plus very important to test vitamin D, folate, ferritin and B12

Private tests are available. Thousands on here forced to do this as NHS often refuses to test FT3 or antibodies

Medichecks Thyroid plus ultra vitamin or Blue Horizon Thyroid plus eleven are the most popular choice. DIY finger prick test or option to pay extra for private blood draw. Both companies often have money off offers.

All thyroid tests should ideally be done as early as possible in morning and fasting.

If on Levothyroxine, don't take in the 24 hours prior to test, and if on T3 don't take in 12 hours prior to test, delay and take straight after

This gives highest TSH, lowest FT4 and most consistent results. (Patient to patient tip, GP will be unaware)

If antibodies are high this is Hashimoto's, (also known by medics here in UK more commonly as autoimmune thyroid disease).

About 90% of all hypothyroidism in Uk is due to Hashimoto's. Low vitamins are especially common with Hashimoto's. Food intolerances too, especially gluten. So it's important to get tested.


Hi SlowDragon,

Tried to send you a reply yesterday but not sure it sent correctly!! So here are my latest test results:-

Vitamin D 111 nmol/L (replete according to Endo)

Folate 22.2 ug/L (range 2.0-18.8)

Ferritin 121 ug/L (range 12-250)

B12 226 ng/L (range 150-1000)

Magnesium 0.92 mmol/L (range 0.7-1.0)

Calcium 2.36 mmol/L (range 2.2-2.6)

TPO 9 kunits/L (range 0-34)

TGO 23 g/L (range 20-35)

TSH 1.91 mU/L (range 0.3-4.7)

FT4 15.6 pmol/L (range 9.5-21.5)

FT3 3.5 pmol/L (range 3.5-6.5)

Gluten free for 2 years

Many thanks


B12 is low, but the others are all good

You might benefit from adding daily sublingual B12 - eg Jarrow 1000mcg

Folate is extremely good

Presumably you supplement vitamin D?

Your TSH and FT4 are mid range, but obviously your FT3 was low.

Don't suppose you tested blood after 6 weeks on constant dose of T3?

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Hi, no I didn't test the FT3 after the 6 weeks, we were away at the time. I have had 3 tests done by Endo's - 3.3, 3.4 & 3.5 - the only thing suggested was the selenium.

I do supplement a general tablet - Centrum over 50's


That probably has several things a multivitamin that you may not want. Eg iodine, copper

Generally best to avoid multivitamins with thyroid problems

Treat specific low vitamins, only if low after testing

Folate and B12 - if low, as yours is, with a good vitamin B complex with folate in and/or sublingual B12

If you are taking vitamin B complex, or any supplements containing biotin, remember to stop these 3-5 days before any blood tests, as biotin can falsely affect test results

Ferritin and vitamin D, must test first and regularly retest as iron and vitamin D are toxic in excess

greygoose can advise on why multivitamins generally not recommended

In fact if have been on these some time, could possibly be skewing result


Looking at that particular multi-vit - and it's pretty awful - I see that it contains iron. So, forget all the vitamins it contains, because you won't absorb any of them, the iron will block them.

Looking at the minerals, it also contains calcium, so you can forget the iron, too, because it will bind with the calcium and you won't absorb either. Doubtful you need calcium, anyway.

It also contains iodine and copper. Neither of which you should take unless you know yourself to be deficient. Iodine supplementation is not recommended for hypos, anyway, because excess iodine - and that's easily achieved - can cause a lot of thyroid problems. As for copper, hypos are usually high in copper, and low in zinc, so you need the copper tested to make sure you don't over-dose on it - which isn't pleasant.

As for zinc, it only contains a tiny amount - 8 mg. It's usually recommended to take 15 mg. So, that won't help much.

55 mcg selenium, the recommended dose is 200 mcg.

100 mg magnesium - it's usually 350 for a woman. And it doesn't even tell us what kind of magnesium it is. As multi-vits usually contain the cheapest, least easily absorbed, ingredients, it's probably magnesium oxide, which won't help you at all.

Multi-vits are a huge con, aimed at the worried-well, who are willing to spend money so that they feel they're doing something to help their health, without knowing what they're doing. The are not intended to help people with nutritional deficiencies. And it's just money down the drain!

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Thank you greygoose - so much information. The Endo's were told I was taking this multivit. - I even think it was the head nurse in the surgery who recommended I take them !! I will go through all my results and rectify the lacking areas.


Never ask any sort of doctor or nurse for nutritional advise, they just know nothing about it!


How active were you before you started T3? If you have had any increase in activities coupled with a elevated pulse rate & if part of your weight loss included fluids, could you have had a deep vein thrombosis(?). Your pulse may have increased to compensate, if your fluid volume decreased.

People can also occlude their lower extremity circulation by placing pillows, underneath their knees. I see people wearing skin tight pants, constrictive clothes have the potential to interfere with circulation too.

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Hi Clarrisa,

I have always been active for my age, walking/running etc. The activities have remained constant. At 63 I have long since given up skin tight pants. Constrictive clothing also !!

Many thanks for your reply.


I experienced very sharp pain in my left chest earlier this year after reaching overhead for something light. I had a similar pain on the right side of my chest a week or two earlier. I was not doing anything unusual. My doctors considered it all non cardiac in nature. I am not on T3. It was odd, painful & transitory, leaving me returning to bed in fear. I haven’t had a recurrence. I am thinking it had to have originated from my spine or kidneys.

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Sorry to hear that. It is amazing just how many things are affected.


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