Thyroid UK
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lab results / NDT dosing

hi, all. still trying to figure out my optimal NDT dose after months (years). labs look like this:

(after previous raises and lowerings and moving from NDT + T3 + T4 to just NDT):

i was on 2.5 grains NDT (raised from 2.25) for six weeks, and labs 16 october were:

Free t4 1.66 (0.82-1.77)

Free T3 4.7 (2.0-4.4)

i had some palpitations at this dose and so given the heart issues and the high result, i dropped to 2.25 grains again. decided to test after 3.5 weeks (although i know that's not really enough time--but one of my good doctors mentioned that it's okay to test after 2 weeks, even if not ideal).

results 19 november, after 3.5 weeks on 2.25, down from 2.5 grains =

Free T4 1.65 (0.82-1.77)

Free T3 4.5 (2.0-4.4)

the lab was the same and i fasted and had the blood draw first thing in the morning both times, so testing conditions were the same. i had also not taken any thyroid med for 18-24 hours prior to the test.

previously, in the summer, i had a much lower lab result on the same 2.25 grain dose, but that was in a different country / with a different lab. (but still with fasting and doing the labs in the early morning and having 18-24 hours without meds before the test). i'm really having trouble understanding. on 2.25 in august, i had the following result:

28 august:

Free t4 15.3 (10.0-28.0)

Free T3 6.2 (3.0-9.5)

maybe there's no point in looking at the august results, maybe the hashi's has been making my thyroid spit out different amounts at different times, maybe the variation in labs makes a difference....? i'm just really confused. why would 2.25 be a middle dose at one point and a high dose at another? leftover high levels of t4 in the system still from previous dosing months ago? more importantly, what do i do now? the 2.25 dose is definitely better for me than the 2.5 was, in terms of heart pounding, but i'm still tired often (and wasn't at 2.5) and my sleep at night is the pits now. i wake up after 4 or 5 hours. i thought i might need to go up again. instead, i can't tell if i need to go down. really, i'm thinking that i should just stay at this dose for a while longer and see how it goes, but it's very confusing. any enlightening details appreciated!

4 Replies

P.S. even with these results, temps are never normal and are always a bit low, which is why i thought i was underdosed. and my hands still get cold from time to time.


Julie11, retesting 3.5 weeks after reducing dose was premature. Levels were still dropping after the reduction. I'd stick with 2.25 grains and retest in 6-8 weeks before making any other adjustment. Symptoms may lag behind good biochemistry by a couple of months so fatigue may improve.

Temperature doesn't always recover when optimally dosed. I've been optimally dosed for a couple of years and no longer have hypo symptoms but I'm still sensitive to cold and usually have cold feet and hands.

Hypothyroid patients often have low ferritin, vitamin D, B12 and folate which can cause fatigue, musculoskeletal pain and low mood similar to hypothyroid symptoms. It's worth having levels checked and supplementing to correct low levels.

Because ranges are so different the only way to compare your Aug results with the more recent results is to calculate where in range your results are. If you were on the same dose your FT4 should be x percent through range in either. If dose changed the results will be different and won't be comparable.


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

thank you! will hold here for a few weeks and see how things go, then.

interesting that temp never recovers for some people. i manage normal (to above normal) temps during the second half of my cycle, but then once my period starts, they always drop back again to below normal, no matter what my thyroid dose is. i wonder if the temp might be related to lingering HPA/ adrenal issues.

the life-long cold hands went away with NDT, but i can't seem to get the overall body temp to go up. that said, i don't usually feel cold. before thyroid meds, the only time i had a normal temp was when i was ill and with fever ('normal' temp for me meant fever).

as a side note, vitamin d and ferritin/% saturation are good, b12 is high on normal blood tests but low on the type of blood tests that look at the past three months of cell activity. i supplement with a methylated b complex but it seems to make no difference. i also take 400 mcg folate (methylated) per day. should i be thinking about taking more? i get severe anxiety with higher doses of b12 no matter what form (i've tried them all).


Julie11, I wouldn't increase folate unless a blood test shows it is low. If serum B12 is high you do not need to supplement high doses.


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.


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