Thyroid UK
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gaining weight on increased Levo !!!

My dose was doubled about 8 weeks back from 50 to 100 - initially lost 5lbs in first 3 weeks !

just been weighed and have now regained the 5lbs plus 3 to spare !! I still feel better than I have in years - what's going on ?? I'm eating really healthily too .

I have upped my exercise quite a lot as was feeling so well - back up to 4 Zumba style classes and a few long walks too in a week !!

Feeling very down about it ... I know weight isn't the be all and end all but I had taken the initial weight loss as a good sign that my body was working again !

5 Replies

cazza1001 Unless you are optimally medicated with a good level of FT3 then losing weight will be difficult. Hard exercise depletes T3 so I imagine 4 zumba style classes a week is adding to that.

If you can post your latest test results, with reference ranges, including FT3 we can see if you have a problem there. If FT3 hasn't been done it would be worth getting a private fingerprick test that includes FT3.


Results today : Hi SeasideSusie - these were done 2 weeks ago ...

Doctor wanted to reduce Levo as TSH slightly surpressed - she's agreed to leave it and retest in 3 months - after I had a fit that she wanted to adjust it as I didn't think my T3 or T4 were high in range ?

My B12 and Folate were abit off but I've started supplementing ...

Is it time for T3 do you think ?

TSH 0.09 ( 0.27 - 4.2 )

T4 15.7 ( 12.0 - 22.0 )

T3 4.6 ( 3.1 - 6.8 )


Ah, that's handy :)

Your FT4: FT3 ratio is 15.7 : 4.6 = 3.41 : 1

Good conversion takes place when FT4: FT3 ratio is 4:1 or less. Your conversion is good.

Your FT4 is 37% through it's range.

Your FT3 is 40% through it's range.

Again, you can see your conversion is good.

You need an increase in Levo which will raise FT4 which in turn, because you are a good converter, will raise FT3.

The aim of a treated hypo patient generally is for TSH to be 1 or below or wherever it is needed for FT4 and FT3 to be in the upper part of their respective reference ranges.

Your pituitary is detecting that you have T4 (by taking Levo) so it doesn't need to send a signal (TSH) to your thyroid to make some, therefore your TSH will be very low or suppressed.

Your GP may panic about suppressed TSH and say you are over medicated (or even say you are hypERthyroid, which you can't be because you're hypOthyroid) but you can't be over medicated as long as FT3 is in range.

From ThyroidUK's main website > About the Thyroid > Hypothyroidism > Treatment Options:

"According to the BMA's booklet, "Understanding Thyroid Disorders", many people do not feel well unless their levels are at the bottom of the TSH range or below and at the top of the FT4 range or a little above."

The book is written by Dr Toft, leading endocrinologist and past president of the British Thyroid Association. It is available on Amazon or from your local pharmacy for about £4.95.

Also, Dr Toft 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 article by emailing , print off and highlight question 6 to show your GP of necessary.

Arrange a new blood test for 6-8 weeks after your dose increase, see where FT4 and FT3 lie and how you feel. If necessary you can ask for a further increase in dose.

Always book the first appointment of the morning when having thyroid tests, fast overnight (water allowed) and leave off Levo for 24 hours (take after the blood draw).


thanks so much for taking the time - so more T4 for me ...

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This might enlighten you a little. Some people don't gain weight on levo but a lot do.

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