Blood tests on NDT: My recent blood test and I... - Thyroid UK

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Blood tests on NDT


My recent blood test and I switched from eltroxin to NDT March of this year.

Could I please ask the experience of the group to cast an eye over them and offer your experience.

T4 free - 10 (8-22)

TSH - <0.01 (0.35 - 4.94)

T3 free - 3.98 (2.89 - 4.88)

Vit D - 113 (50-125)

Vit B 12 - 375 (120-650)

Folate - 7.5 (3.1-19.9)

Ferritin - 32 (11-307)

11 Replies

B12 should be around 800, are you supplementing?

Your ferritin could be a little higher - vit c will help

Free t3 and free t4 need to be higher in the ranges

How do you feel? When had you last taken ndt prior to blood taken?

Jojo887 in reply to Chippysue

Not supplementing as my bloods in March were

B12 /1355

So I’d stopped.

I currently take 2 grains and before bloods were drawn I took last ndt at 15:00 previous day none on the morning of bloods?

Should I increase ndt would this help with free t4 and free t3?

I’m starting iron supplements 4 hrs away from ndt and starting b12 today along with selenium.

Thank you for your response it is very much appreciated.

Chippysue in reply to Jojo887

B12 - I take every day for a couple months and then just take once or twice a week to keep levels up.

Vitamin c - a good quality one will increase your iron. Iron supplements are not recommended - I would see a nutritionist. Do you have a good independent health shop nearby?

Yes if I were you I would increase ndt to bring your free t3 and free t4 up, I cannot advise for you to do that, this is just what I would do.



Hi Jojo887, most improtantly - how are you feeling? Do you have your original bloods from when you were diagnosed? What does of eltroxin were you on? What is the dose of NDT and type?

Vit D is great, B12 can be higher, folate and ferritin most definitely too.

How many hours exactly did you have between last NDT dose and testing - this is really important.

Jojo887 in reply to Hidden

My last ndt taken at 15:00 day previous and bloods were drawn at 10:30 am next morning so about approximately 18hrs apart.

I had bloods done on the 03/03/18

Magnesium 0.86(0.66/1.07)

Folate >20(3.9/26.8)

Free T3 10.13 (3.10/6.80)

Free T4 19.3(8.5/22.0)

Tsh 0.01(.27/4.20)

Ferritin 71(13/150)

I was on 75mg eltroxin every second day and 100mg alternate days

I made switch myself as doctor won’t supp ndt so I sourced thyroids myself and slowly built up to 2 grains

I’m feeling tired but have other autoimmune illness and immune suppressing meds for this. I have half thyroid removed in 1997 and 5mm nodules growing on the remaining thyroid which feel like my swallowing has been affected since 2016

Hidden in reply to Jojo887


Ok so you should have a gap of 8-12 hours between meds and testing, 18 hours is too long, so with your FT3 mid-range, you definitely don't need an increase.

So these were bloods on eltroxin, do you have bloods before any meds, the original bloods at time of diagnosis?

Do I see correctly that 75/100 mcg eltroxin your ft3 was over 10 on a scale up to 6.8? Why have you switched to NDT?

Jojo887 in reply to Hidden

No sorry those bloods in March were a month into Ndt previous bloods on eltroxin were

November 2017

T4 free /16 (8/22)

Tsh 0.51 (.35/4.94)

Free t3 3.92 (2.63/5.69)

Anti tpo <33.40

Anti thyroglobulin <244.0


I would not increase my ndt if I were you as your tsh indicates the body isn’t needing to produce thyroid hormones and your t4 and t3 levels are in line with not having taken the ndt for well over 12 hours so no need to increase those. Your ferritin is too low it should be closer to 90 so def supplement for a month or two along with vit c. B12 should be top end of normal range. The important thing is how are you feeling? Do you have more energy than when on eltroxin and are your hypo symptoms fading?

From my own experience with ndt, I would suggest that you give your body time to adjust and certainly your test results would not indicate a need to increase your dose but your iron levels need attention and this will help your body utilize the ndt properly.

I was very deficient in magnesium and found supplementing with it very helpful in alleviating anxiety and dealing with stress better - best forms glycinate, malware or taurate imo.

Best of luck


Jojo887 in reply to Finola

Hi Finola

Thank you very much. I’m definitely so much better going on ndt it’s just a shame your not monitored as much with dr but I’ve been plaguing them and now pay extra for blood tests so that I can keep an eye on them myself

I would definitely ask for an increase in dose. You are way to hypo. With your FT3 being where it is, that is showing that you are converting the T4. However, both levels are too low. Many people that use DTE/NDT fing that splitting the dose works better for them. Also, when did you take the pill and go for the blood work? I find that taking my 1/2 AM dose, go for BW 7 - 8 hours later, then take the PM dose is best in checking my FT3 level.

Also, it is common for the TSH to be more suppressed in people that use NDTs. As long as you are getting good, adequate doses of T4/T3, it is ok. I would not want it to drop lower, but base how you feel on the FTs, not the TSH (a pituitary hormone that regulates thyroid gland hormone) w/o a thyroid there is no regulating it.

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