Estimated bio-availability of NDT

[Naomi8]

I grain of NDT usually contains 38mcgs T4 & 9 mcgs T3,but its bio-equivalent is usually stated on this forum as anything from 75mcgs to 100 mcgs of thyroxine,with its T3 content equivalent to 3,sometimes 4 times that amount of thyroxine.

Is this all anecdotal-hence the variation?

I'm still looking for my"sweet spot"having gone up from a 16 to an 18 dress size & am experiencing low energy reserves & a lot of fatigue.

I have been on NDT about a year.I worked up to 3 grains but my FT3 was over range,the highest its ever been,even higher than when I was on too much T3-only & lost SO much hair.

Why am I still gaining weight?Why the low energy reserves & constant fatigue?

All feedback is invaluable,especially other peoples' experiences.

[greygoose]

It's impossible to say exactly how much T4 x amount of T3 is equal to. They're not the same thing. And, if you can't convert the T4 it isn't equal to anything. They are just rough guesses to help people transit from one to the other, but don't have any scientific basis.

[Naomi8 in reply to greygoose]

Many thanks Greygoose.I gave up thyroxine-only after 16 years.I then had 2 years on T3-only.Energy levels were much improved,but hair thinning was extreme & mood was unstable,culminating in a second overnight crash into depression with extreme daily anxiety.

Its a long jounrey!Until my thyroid failed in 1998,I was a size 14.I was a 16 within the year,but stable.Now I'm an 18.I'm 5ft 9 so I don't look overweight,but I am actually 2 stone overweight.Its so difficult to get enough excercise when fatigue & poor energy reserves are a constant.If I have a day of good energy & make the most of it,it is followed by 3 days of debilitating fatigue.

[greygoose in reply to Naomi8]

If I were you, I would forget the exercise until your FT3 levels are greatly improved. It's not going to make you lose that weight, anyway.

[Hidden]

The pharmacy said roughly 1 grain NDT was equivalent to 75mcg levo.

[Naomi8 in reply to Hidden]

That's the measurement I use,just curious as to why some use 100mcgs.Having been on NDT for nearly a year,I would not say one grain is equivalent to 100mcgs

[helvella Administrator in reply to Naomi8]

I have said many times, I believe that the manufacturers (e.g. RLC/Nature-Throid) use 100 micrograms as a very cautious conversion. That is, if you change from levothyroxine to desiccated thyroid using that factor, you are almost certain not to over-dose. Then you can adjust as needed.

(However, it does mean that anyone converting from desiccated thyroid to levothyroxine could very easily end up taking too much levothyroxine!)

[Naomi8 in reply to helvella]

Good point!Never heard of that!I worked up to 3 grains very slowly,then tested.FT3 was in the sevens & I didn't want a repeat of the hairloss on T3-only

[Naomi8]

I agree

[ShinyB]

Have you looked into adrenal support? Dr P told me that the body has trouble using thyroid hormones properly if your adrenals are suffering. It's early days for me in terms of trying adrenal support, but just thought I'd mention it in case it helps