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Interesting article: mild TSH suppression gives closest to normal thyroid function in levothyroxine monotherapy for this group

Ito et al (2017) Biochemical Markers Reflecting Thyroid Function in Athyreotic Patients on Levothyroxine Monotherapy

, Thyroid , Vol 7 No.4

Conclusions: The serum biochemical markers of thyroid function in patients on levothyroxine monotherapy (LT4) following total thyroidectomy suggest that the patients with mildly suppressed TSH levels were closest to euthyroid, whereas those with normal TSH levels were mildly hypothyroid and those with strongly suppressed TSH levels were mildly hyperthyroid.

Methods: A total of 133 consecutive euthyroid patients with papillary thyroid carcinoma who underwent a total thyroidectomy were prospectively studied. The patients’ serum levels of lipoproteins, sex hormone-binding globulin, and bone metabolic markers measured preoperatively were compared with the levels measured at postoperative LT4 therapy 12 months after the thyroidectomy.

Results: The postoperative serum sex hormone-binding globulin (p<0.001) and bone alkaline phosphatase ( p < 0.01) levels were significantly increased in the patients with strongly suppressed TSH levels (£0.03 lIU/mL). The postoperative serum low-density lipoprotein cholesterol levels were significantly increased ( p < 0.05), and the serum tartrate-resistant acid phosphatase-5b levels were significantly decreased ( p < 0.05) in the patients with normal TSH (0.3 < TSH £5 lIU/mL). In the patients with mildly suppressed TSH (0.03 < TSH £0.3 lIU/mL) and fT3 levels equivalent to their preoperative levels, all metabolic markers remained equivalent to their preoperative levels.

[ Edited 12/06/2017 by admin to add freely accessible link to full paper:

ncbi.nlm.nih.gov/pmc/articl... ]

9 Replies

Thanks for posting but were the researchers only concentrating on the results. What was the patients' viewpoints on their dose? Did they feel well with relief of symptoms?

I don't know how patients who have had TT cope with being on levothyroxine alone.


Hi they acknowledge that this is a limitation. But I thought it was interesting given that TSH within range is generally considered to be the gold standard by the medical profession, whereas this is suggesting that some suppression of TSH was needed for these patients to be in the same range for other markers as before their thyroid was removed.


Thanks for posting, I find this article interesting as I feel better with a suppressed TSH and have to fight with doctors not to adjust my medication .

1 like

A TSH within range is o.k. if the person hasn't been diagnosed with hyporthyroidism. If diagnosed TSH should be 1 or lower so I believe they are very mistaken or badly trained if they thing anywhere in the range is o.k.


Plenty of long words and sentences that don't make any sense to me.

It's a pity that all those words concentrate on blood levels and there is no mention of how well the patients feel.

I am athyreotic and I feel darned awful on levothyroxine whatever dose I take and I couldn't care less what the blood tests show or whether I am diagnosed as euthyroid - I still feel awful.

Now on NDT and wouldn't change back......EVER!


I am glad you are well on NDT and it is a great feeling when symptom free - no doubt about that


I think they have missed the fact that TSH governs conversion of T4 to T3. So the more it gets suppressed, the worse conversion gets.


Would you please add references to that?



I've also come across it at some other sites but I cannot find them now.

And I have my blood results to prove that. Every time my TSH was lower than 1.60, my conversion would get worse and FT3 would fall, FT4 would go up, and I would feel more symptomatic. You can see a pattern throughout my results: every time TSH is higher (not above 2.50 of course), FT3 is higher too (and I will feel less symptomatic or asymptomatic) and FT4/FT3 ratio is closer to 3.33 - which would be the ratio of FT4/FT3 of a healthy thyroid - it may even be less than 3.33 in healthy people, but we, as thyroid patients, cannot go below 3.33 when on T4.


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