Log in
Thyroid UK
93,628 members107,661 posts

Latest results after T3 dose increase

I've just got my latest blood results following T3 increase from 25 to 31.5mcg. I'm pasting also my previous results for you to comment and advise as I'm quite concerned about my T4 decreasing since I started T3 and currently it's below the range. Generally I feel much better than when I was on 150mcg T4 only when my blood results looked better. I have even managed to lose 7kg that was impossible before. My mood is also much better.

22.11.17 - 31.25mcg T3 + 100mcg T4:

TSH 0.009 (0.27 - 4.2)

FT3 5.34 (3.1 - 6.8) 60.5%

FT4 11.3 (12 - 22) -7%

14.08.17 - 25mcg T3 + 100mcg T4

TSH 0.024 (0.27 - 4.2)

FT3 5.2 (3.1 - 6.8) 56.8%

FT4 14.4 (12 - 22) 24%

15.05.17 - 12.5mcg T3 + 100mcg T4

TSH 1.6 (0.27-4.2)

FT3 3.71 (3.1-6.8) 16.5%

FT4 13.49 (12-22) 14.9%

20.12.16 - 150mcg T4 only

TSH 0.12 (0.35-5)

FT3 4.3 (2.6-5.7) 54.8%

FT4 17 (9-19) 80%

Please comment and help me understand what is happening with my T4 levels. Is that anything to worry about? Should I correct it by increasing T4?

Also my endo is concerned about very low level of TSH saying it will cause osteoporosis.

Please advise. Your help is always greatly appreciated.

4 Replies


T4 is a pro-hormone which converts to T3. It is quite common for FT4 to be lower on Levothyroxine + T3 combination than it is on Levothyroxine only. It's not necessary for FT4 to be high when taking T3 direct and as long as FT3 is good you are optimally dosed. FT3 5.34 is good, just a little shy of the upper third of range.

TSH 0.009 is very suppressed. Most doctors and endos are concerned that suppressed TSH increases the risks of osteoporosis and of developing atrial fibrillation. I argue with my endo about this and have said I prefer to feel well today with sufficient T4+T3 and accept that it may increase my risks of developing adverse health events in the future. A paper I'm fond of quoting finds no association between TSH and atrial fibrillation but doesn't address osteoporosis. press.endocrine.org/doi/abs...


Thanks Clutter :)


Personally I get symptoms from my FT4 being low, even though my FT3 is at top of range. On T3/T4 combo.

My T4 was reduced when I started T3.

Increasing my T4 back up has helped reduce symptoms


Many thanks SlowDragon.

Haha everybody is different! I was previously on 150mcg T4 only and though my hormones levels looked pretty good I was feeling awful and symptomatic. I didn't tolerate T4 well from the very first tablet. Adding T3 improved my symptoms I'm much better now, do not have headaches, migraines, heart problems and finally lost some weight.

Thanks for sharing your experience :)


You may also like...