Thyroid UK
82,815 members97,844 posts

low Rt3 ratio

Just got my lab back: 

6. april,4 days after increase to 135 mg NDT . It was necesarry to use anorther lab which had the Rt3 test avaiable:

TSH 2,26 (range 0,5-3,6)

Free T4 13,4 (range 8-13,0)

Free T3 5,8 (range 2,7-6,3)

Rt3 0,34(0.14-0.54

This gives ratio of 17,1

I then took a scheduled test on the 18 of april:

TSH 2,1(range 0,2-4,0)

Free T4 15,7 (range 11-23,0)

Free T3 5,8 (range 3,5-6,5)

This is the best results during this winter. On all the other tests I had a TSH around 3,5 so I had been clearly undermedicated.

Now,question is. Im still feeling crap but maybe a bit better than in march. Mid march I did a hard exercise training camp with 3 days(during 4 days,1 day rest) 

Could this be causing the bad rT3 ratio? I starting to worry if I am doing something wrong. I also understood that excess Ft3 could cause this but since my TSH had been elevated I cannot understand this. Nowadays Im to exhausted to do bike training. I just go for 30 mins walk

6 Replies


It's high rT3 which can be problematic, low rT3 isn't seen as an issue.

You can increase dose at 2 week intervals until TSH is <1.0 as long as FT3 remains within range.  Until you are optimally medicated it would be best to avoid strenuous exercise which depletes T3.


I am not a medical professional and this information is not intended to be a substitute for medical guidance from your own doctor. Please check with your personal physician before applying any of these suggestions.

1 like

I think you missunderstood. Ratio Rt3/ft3 is low. Meaning that Rt3 is high



rT3 0.34 is mid range, it isn't high.


Clutter, so even if ratio is below 20 I should not worry?😊



No need to worry.


THx, Clutter! Final question. I worry mostly of my higher pulsrate. With every increase there was a faster Pulse. I go back one year and see that now Im 20 beats higher in Resting state than last year on the same dose(from 55 to now 75) . I dont know what to think. Sit it out and hope it settles lower?  


You may also like...