Low TSH, help with results, please?

[1966sll]

So I started on Levothyroxine when my TSH was 3.9mU/L and had associated Hypo symptoms. The reference ranges are TSH: 0.570- 3.6, T4: 7.9-14 and T3: 3.1-6.8. Previous results on 75mcg Levothyroxine were:

TSH: 0.04 mU/L

Free T4: 17.3 pmol/L

Free T3: 5.7 pmol/L

My dose was decreased to 50mcg Levothyroxine and below are the results of this decrease in dose over 6 weeks.

TSH: 0.012mU/L

Free T4: 14.9 pmol/L

Free T3: 5.4 pmol/L

My TSH has become even more suppressed, although my T4 and T3 and have dropped slightly. I feel fine in myself, and feel I'm definitely better being on the medication rather than not.

Any thoughts on these results? I'm just a bit concerned about the TSH being so low and I can't speak to my doctor about it until next week when there's an available telephone appointment.

[bantam12]

It doesn't matter that your tsh is low, it's not important, what is important is the level of your T3 which looks good.

[SeasideSusie Remembering]

1966sll

I agree with Bantam. Doctors don't like low TSH levels, but Dr Toft, past president of the British Thyroid Association and leading endocrinologist, states in Pulse Magazine (the magazine for doctors):

"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).*"

*He recently confirmed, during a public meeting, that this applies to Free T3 as well as Total T3. You can obtain a copy of the article by emailing Dionne at

[e-mail]

print it and highlight question 6 to show your doctor.

If you feel fine on 50mcg Levo then there doesn't appear to be any need to reduce it as your FT3 is only 62.16% through it's range.