Thyroid UK

Reverse T3

Reverse T3

Hi I just want to make sure I'm interpreting this correctly. I've been on NDT for a few years now- my FT3 is 3.77 pmol/l my reverse T3 is 12ng/ DL using the STTM site my ratio is 20.9 they say if it's >20 you don't have a RT3 problem...

The range for FT3 is (3.0 -5.9 pmol/l)

The range for RT3 is ( 8-25 ng/DL)..

My last 5 Ft3 results were

16/08/09 3.77

16/06/01 4.22

16/01/11 4.56

16/01/25 5.17

My T4 is always below range - in January my NDT was decreased from 120 mg to 90 mg in June it was increased back up to 120 mg but my T3 kept dropping despite B12, added iron selenium etc. Absolute clean diet.

Should I increase my NDT ? I've asked to be increased to 150-180 mg but maybe T3 added to NDT would be better? Any thoughts? I'm a bit concerned with my borderline t3/rt3


4 Replies

Hi Karen, so you are on two grains now? It takes a while for the body to adjust to a new dose. Why did they ever reduce your dose when you seemed to be doing well in Jan.

I wonder how you arrived at your ratio? I tried changing your 3.77 pmol to ng/dl and it came to .2929 ng/dl. since I couldn't seem to get your reverse T3 into pmol. I'm not sure that works either on the STTM calculator.


i seemed hyper because my tsh was too low 0.06 (range is 0.1 -4) I don't think when your on NDT that tsh or t4 mean anything.. I've been on 120 mg since May- beginning of June over 2 months but my T3 and T4 are still decreasing... Feel like complete shit and exhausted.. Depressed feel done and defeated it's fecked.. The NDT is increased as of today to 2.5 grains so 180 hoping that helps.. I have to be at my conversion charts to calculate how I did it.. Cheers


Sorry for the way you feel. It is dismal because so many factors have to come together. Maybe your increase will fix it. It's too bad the TSH caused him to change your dose especially when your FT3 was so great. I'm not sure what is happening but it doesn't seem your reverse is the problem since it is low in the range. One other thing which could cause a lower FT3 is your adrenal gland.


So the conversion is

FT3 = 3.77 pmol/L * 650.97349 g/mol = 2454.2 ng/L

2454.2/L x 1 L/10 dL = 245.42 ng/dL FT3

12 ng/dL RT3

Ratio: 20.5

STTM recommends a ratio of <20 but considering my ft3 is so low ie. Lower 25 percentile...raising my NDT could cause more issues? So I should possibly be adding T3 only?


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