Thyroid UK
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Bloods after stopping thyroxine

My endocrinologist said stop thyroxine, I was on 75mcg daily, she wanted to see my results off it. My T4 has not changed much at all on it

Tsh has reduced from 36 to 8 but T4 remains around 16 with or without treatment. She did a separate assay?? No interference was seen and she suggests Addenbrooks for thyroid resistance or adenoma??? I have been off thyroxine for 3 weeks and am tearful, skin is very dry, eyes so dry, freezing cold, episodes of tachycardia... I did bloods yesterday after 3 weeks will they show enough as she wanted me off for 6 weeks but I'm feeling worse daily.. any advice pls

6 Replies

What a sadist! So you were taking 75mcg T4 and your TSH was still well over range and your doctor said to stop taking levo instead of giving you an increase. Blimey! yes it could be a TSH-producing adenoma, but a free T4 of 16 is not high is most ranges (barely mid-range in the most common ones) and you don't give a free T3 result so that could be rock bottom. Do you take B vitamins (as biotin can give a false free t4 reading if taken within a week of the test)? Your symptoms now suggest severe hypothyroidism. I'd see another doctor and get your levo back ASAP before you become really ill. You'd think that your doctor could just look at your results from before you started levo!


But 75mcg was not a high dose, only 25mcg up from starter dose. Many people need 150mcg, some even need 200mcg.

Dose should be increased in 25mcg steps until TSH is around one and FT4 towards top of range and FT3 at least half way in range

Can you add results from when you were on 75mcg

Do you have Hashimoto's, also called autoimmune thyroid disease, diagnosed by high thyroid antibodies

Have you had vitamin D, folate, ferritin and B12 tested

NICE guidelines saying how to initiate and increase. Note that most patients eventually need somewhere between 100mcg and 200mcg Levothyroxine

Dr Toft, past president of the British Thyroid Association and leading endocrinologist, states in Pulse Magazine,

"The appropriate dose of levothyroxine is that which restores euthyroidism and serum TSH to the lower part of the reference range - 0.2-0.5mU/l.

In this case, free thyroxine is likely to be in the upper part of its reference range or even slightly elevated – 18-22pmol/l.

Most patients will feel well in that circumstance. But some need a higher dose of levothyroxine to suppress serum TSH and then the serum-free T4 concentration will be elevated at around 24-28pmol/l.

This 'exogenous subclinical hyperthyroidism' is not dangerous as long as serum T3 is unequivocally normal – that is, serum total around T3 1.7nmol/l (reference range 1.0-2.2nmol/l)."

You can obtain a copy of the articles from Thyroid UK email print it and highlight question 6 to show your doctor

 please email Dionne at

Also request list of recommended thyroid specialists. Yours sounds like a Diabetes specialist

Professor Toft recent article saying, T3 may be necessary for many otherwise we need high FT4 and suppressed TSH in order to have high enough FT3

Official NHS guidelines saying TSH should be between 0.2 and 2.0 when on Levothyroxine

(Many of us need TSH nearer 0.2 than 2.0 to feel well)

See box

Thyroxine replacement in primary hypothyroidism


Thank you, The issue I have is awful tachycardia and what endo described as pt presents with symptoms of thyrotoxicosis on any dose above 75mcg I'm not even great on that. Nervous anxious sped up I was ok on 50mcg but Tsh kept rising on that in 75 my Tsh stays around 8 !!! I feel at such a loss


Essential to get vitamins and antibodies tested

Low vitamins can be significant issue, especially if high antibodies

You may need a beta blocker to help counter palpitations and hyper symptoms while dose of Levothyroxine is increased to high enough level.

For full Thyroid evaluation you need TSH, FT4, TT4, FT3 plus TPO and TG thyroid antibodies. Plus vitamin D, folate, ferritin and B12.

Essential to test thyroid antibodies, FT3 plus vitamins

Private tests are available

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 and don't take Levo in the 24 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)

1 like

Agree with AotN's comment above, please see another doctor as soon as possible. 75 mcg of levo is a low dose, and one which cannot possibly indicate resistance to thyroid hormone. For that, you would need to have titrated up to a much higher dose of T4, found that ineffective, and then started the same process of careful titration on T3 monotherapy. Resistance syndromes require very high doses of T3, often well over 100 mcg.

If you found yourself only experiencing a degree of recovery with that level of T3 dose, then certainly, a referral to Addenbrooke's would be worthwhile. Even so, not all cases of resistance to TH can be picked up by the specialised genetic testing they do there.


A fast heart beat can be a sign of low T3 (the active thyroid hormone). It may be that your body is unable to convert levo to sufficient T3 - did the doctor do an FT3 test?

My hypothyroid other half’s rapid heart rate only started to slow when she was prescribed liothyronine.

Your doctor sounds awful. Poor you x


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