GP speaking to endocrinology about suppressed TSH

[Tjqui00]

I posted yesterday about my test results. My TSH has been suppressed for many years and the recent results shows ft4 fairly high in range and ft3 mid range. One doctor said to stay on the same dose, another said to reduce the dose which I didn’t agree with as my ft3 is now the lowest it’s ever been. She is now getting advice from endocrinology about my suppressed TSH because they think I need to keep reducing my dose to get the TSH in range. I’m so anxious now waiting to hear back because I feel what endocrinology say I will have to do.

[SlowDragon Ambassador]

ft4 is now 16.5 when range goes up to 18 and ft3 has dropped from 6,6 to 5 (range 3.8-6).

Free T3 (fT3) 5 pmol/L (3 - 6) 

Ft3 66.7% through range

Refuse to reduce as Ft4 is within range and Ft3 only 66% through range

Meanwhile get vitamin levels retested

7 months ago they weren’t brilliant

ferritin is 52,

vitamin b12 level 462 ng/l,

serum folate level 16.5 ng/l (range 3-20),

vitamin D 90.

aiming for ferritin at least over 70

B12 over 500

[Tjqui00 in reply to SlowDragon]

The ft3 upper limit is 6. My ft3 result in May was 6.6. The doctor said they can refuse to put be back to 100 mcg. Worried if the endocrinologist says to reduce to 75 every day, doctors will say that I have to go by what they say.

[SlowDragon Ambassador in reply to Tjqui00]

Well at 100mcg every day your results did suggest dose was too high

What’s range on Ft4

Current dose seems about correct

Next step is

A) stay on current dose and retest in another 8 weeks

See if levels are stable or going up or down

Meanwhile

B) check all four vitamins are at GOOD levels

If not, work on improving

Approx how much do you weigh in kilo

And is your hypothyroidism autoimmune

[Tjqui00 in reply to SlowDragon]

I’ve only just seen your reply. I have hashimotos, TPO antibodies were over 1000.. I weigh about 52 kg. I’ve actually put a few pounds on, used to be 50 kg.

[SlowDragon Ambassador in reply to Tjqui00]

low vitamin levels are especially common with Hashimoto’s

Gluten and dairy intolerance both possible issues

Always worth trying strictly gluten free diet

And few months later dairy free too

So guidelines of 1.6mcg levothyroxine per kilo per day …..suggests 83mcg Levo per day

But some people need a bit more and some a bit less than guidelines

[Sparklingsunshine]

The issue is if your TSH has been suppressed for may years, and this can be a common problem with hypos, it might never rise or not enough to satisfy a doctor. It assumes that you still have some thyroid function of your own left to respond to the lower dose of meds that they will invariably insist you take.

You could be left on lower doses of Levo and with corresponding lower levels of FT4 and FT3, which will make you unwell, but your TSH might still remain suppressed. The HPT feedback loop often doesnt work properly once we've been on thyroid replacement for years.

Doctors cant seem to differentiate between a supressed TSH due to being truly hyper and one suppressed due to being on thyroid meds, but with FT4 and FT3 being in range.

[Tjqui00 in reply to Sparklingsunshine]

I keep trying to explain that to the doctor, but they won’t listen. They don’t agree with me.

[TaraJR]

This is the bane of our lives. Check my post on this a little while ago:

healthunlocked.com/thyroidu...

[helvella Administrator in reply to TaraJR]

TaraJR - Endos' quotes on suppressed TSH v high T4/T3

Problems caused by suppressed TSH or high T4/T3?

Leading endocrinologists, well-known in UK and abroad, were asked by a co-lead of ITT Improve Thyroid treatment patient group:

“Is it a suppressed TSH itself or high/over range T4/T3 themselves that can lead to problems eg osteoporosis or atrial fibrillation?” They all said it is the T4/T3 levels…

My quality of life before taking T3 was awful, and I wasn't bothered if I was here or not. Since taking T3 I am vastly better, although my TSH is now suppressed. There are papers showing that the extra risk from a suppressed TSH is small, and I’m willing to take that very small risk. The decision should be a joint one between doctor and patient.

A very low TSH may carry an additional slight risk but, to me, well worth the trade-off against having a decent quality of life. An elevated TSH is as hazardous as a low TSH, or perhaps more so.

Tara Riddle, September 2024

Link to the full document as a PDF:

dropbox.com/scl/fi/trzzzgo4...

Last updated 28/12/2026

Link to this blog:

helvella.blogspot.com/p/tar...

[Tjqui00 in reply to helvella]

Is there a slight risk with very low TSH? Mine has been undetectable for many years.