Thyroid UK
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Low TSH?

Hi guys

I'd like some advice please.

My results for February were

TSH 0.99 (0.3-5

FT4 12.17 (8.4-19.1

FT3 5.1 (3.8-6

May results

TSH 0.07 (0.3-5

FT4 16.1 ( 8.4-19.1

I'm feeling tearful and tired and not sleeping too well, dr didn't seem worried about low Tsh. Should I lower my thyroxine? I take 125 mcg a day.

My B12 and vitamin D are all optimal, which is great. I take selenium and B complex and solgar iron gentle.

Any thoughts thank u :)

9 Replies

Ndobins How did you feel on a lower dose of Levo? Your current results don't indicate that you need a dose reduction, but it's not all about numbers.

No FT3 this time?

Now that your B12 and Vit D are optimal, don't stop supplementing or they will plummet again, you need maintenance doses now to keep the levels where they are.

Are you taking 1000mg Vit C along with your iron?


Yep vitamin c, and K2 with vitamin D. I was taking 10,000 a day, it was 44 now back up to 125 👍 I'm injecting b12 still twice a week, may up that again. Have been on 125 levo for a while now, felt better for it too. Is that TSH not too suppressed now? I'm taking 5000 vitamin D along with Spray, going to keep that up now . Thank u x


You don't have to worry about suppressed TSH, taking any form of thyroid meds means that your pituitary gland detects that thyroxine is there so it doesn't need to send a signal to the thyroid to produce any, that signal being Thyroid Stimulating Hormone (TSH).

In 'Treatment Options' on ThyroidUK's main website, there is an article by Dr Toft, past president of the British Thyroid Association and leading endocrinologist, in which he states

"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)."

So it's FT3 that is the most important test.


Ok great I feel better about it now, I may as you say keep taking the vitamins and mineral properly and see how I go. She didn't do FT3 this time as I was having my hormones tested as trying for a baby , she just didn't thyroid too . I look for the article , thank u x


Here's a link to the page where you'll find Dr Toft's quote, scroll down to Treatment Options:

If you want a copy of the article then you can email . It's question 6 I believe.

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I shall have a read, good advice as ever 👍


If your D3 is now at 125, since it's summer, I'd consider dropping back to 1000iu-2000iu a day and making sure to take magnesium and K2 as well.


It was 44 in February so dr prescribed 10,000 once a week but I followed the vitamin D council protocol of 8,000 a day and it's now 125, I thought a maintenance dose would be around 3,000 a day? I'm outside a fair bit ( have horses ) I'm taking K2 and I've been a bit slack with magnessium but I've just ordered a good one ( it helps me sleep) 😊


Winter maintenance dose is generally considered to be 2000iu

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