Suppressed TSH, T3 and T4 within range

[Collie]

Any advice would be very much appreciated.

My endocrinologist always wants me to reduce T3 and in letter asked me to reduce to15mcg (currently on 20mcg T3 and 75mcg T4). I have tried reducing to 15 mcg by cutting the 20 mcg tablet...

I actually paid for a thyroid test as I hadn't seen the endocrinologist since before Covid19 (UK) started. I wanted to check T3 and TSH levels after reducing T3 for over a month. My dose was probably lower than 15 mcg due to method of cutting the tablets (very powdery).

Results were:

TSH was 0.01 (it's usually 0.02!) - Range 0.27-4.2

Free T3 was 5.1 - Range 3.1-6.8

Free T4 was 15.5 - Range 12-22

My resting heart rate is usually 55-58, but went down to 53 and even 43 at one point after reducing T3. I do go jogging 3 times a week and I do well over 10,000 steps every day, but I'm not an athlete! I also noticed an increase in depressive thinking on the lower T3 dose (I do have the DIO2 polymorphism - heterozygous, though).

As I was concerned about my low resting heart rate and depressive thinking I have gone back to 20 mcg T3. I'm seeing a different endocrinologist later this week.

I can't understand why my TSH is so low when I don't have any obvious hyper symptoms.

Would stress suppress my TSH? (I do have something to be stressed about at the moment).

[Lalatoot]

Collie taking t3 generally suppresses TSH. My TSH is undetectable. Has been since I started with t3. I do not consider it a problem as long as your hormone levels are in range and yours are well in range.There are 3 elements to the thyroid tests, tsh, ft4, ft3. 2 out of those 3 suggest that your medication did not need reduced and you felt well on those doses of medication.

[Collie in reply to Lalatoot]

Thank you so much for the reassurance. I have not felt well reducing the T3 (but the endocrinologists do worry me with osteoporosis/atrial fibrillation warnings).

[diogenes Remembering in reply to Collie]

A simple answer for any endocrinologist. OK, there is a small extra risk of AF and OP, but it's tiny compared with other causes. What would you have me do? Feel under the weather for the rest of my life, or perhaps shorten it (if at all) a little by going on as I am? I have the rest of a life to live, not a box to tick to your satisfaction..

[Collie in reply to diogenes]

Thank you, Diogenes.

That's just what I told the endocrinologist years ago who first asked me to reduce T3. In future I'll continue to go by how I feel

(Family members who had never taken T3 or any other thyroid meds had osteoporosis. I have it slightly and osteopenia on DEXA scan pre covid, but was severely deficient in D3 and have coeliac disease that was diagnosed very late).