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Thyroid UK
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switched from Armour to Erfa, not sure what to think

I have a question on NDT:

I was put on Armour in 2012 but, this summer, my doctor decided it was not working for me, and switched me to Erfa. On 5 grains of Armour daily, my labs (24 hours after latest dose) were:

TSH 0.0001

FT4 1.3 (ref 0.8-1.8)

FT3 2.9 (ref 1.8-3.8)

However, since those labs show my levels 24 h after latest dose, I wonder what they would have looked like if I had taken Armour before going to the lab...?!

Also, on 5.5 grains of Erfa (according to my doctor, the equivalent of 5 grains of Armour), my levels were:

TSH 0.0001

FT4 1.3 (ref 0.8-1.8)

FT3 3.7 (ref 1.8-3.8)

My doctor said this proves that Erfa is working better for me than Armour...however, since going on Erfa, I have just not felt right...some days, I feel really good, only to feel lousy the next, and I seem to go from hypo to hyper back to hypo, etc...

I always go to the lab 24 h after latest dose. Could my results on 5.5 grains of Erfa indicate that I am overmedicated on Erfa as my FT3 levels were at the very top of the range 24 h after taking it...?!

Also, since I never had thyroid labs before developing a thyroid problem, I have no idea what "ideal" thyroid labs are supposed to look like in an euthyroid (healthy) individual. Has someone had labs while healthy, and could post them here, just to give me an idea...?! I know you should not care about the TSH when on meds containing T3, but I would be interested in finding out what the free Ts are "supposed to" look like in a person without thyroid disease...

12 Replies

I think that's one of the problems, most of us have never had a thyroid hormone blood test whilst well.

Blood tests should only be used as a guide. This is the best way to treat us:-


Some people find different NDTs have different affects on them. So your GP is only going by the blood tests and doesn't seem to be listening to you. The problem is they don't understand why we are still complaining when our blood results seem 'perfect'.

Some patients on Erfa started complaining early this year and it was denied by the company that there had been any changes:-



I thought a T3 reading of a "healthy" person is 60-80% of range. I certainly feel best when my T3 is in this band. I've not felt well nearer to the top of the range and I have never been as close as you.


That is interesting, because I have been wondering lately if I am not overmedicated on my current dose of Erfa...I am losing a lot of hair, yet I still have some odd hypo symptoms, like fluid retention and problems losing weight...

I think I will go back to the Armour I still have left and see what happens...


How did you feel on Armour because your results look better on that?

Some of your "hypo" symptoms might not be related to the thyroid at all of course.


I felt great on Armour for the first six months (December 2011-June 2012), while taking smaller pills (up to 120 mg), then switched to 240 mg pills and started going downhill. Suspecting that the fillers and binders differ between strengths, I asked to be put back on 120 mg, but I have not had the same success with Armour since; I have no idea why. Maybe I should give it another try...? I have been kind of scared by the STTM Armour hysteria...

I read somewhere that a healthy thyroid gland produces roughly 100 mcg of T4 and 20 mcg of T3 daily, which would mean 2.5 grains of NDT. I tried that once, and felt more dead than alive after a few weeks. My TSH ends up suppressed the minute I add something containing T3, even if it's as little as 15 mg of NDT...

Before going on NDT, I was seeing a doctor who believed that thyroid patients only need T4. On the other hand, unlike most conventional doctors, he also believed that Hashimoto's patients like me need a suppressed TSH in order to keep the antibodies down. I have had a suppressed TSH for years (before going on NDT in late 2011, I was on 200 mcg of T4 for seven years, which kept my TSH between 0.05 and 0.1), and my anti-TPO levels in range (they were +6000 at the time of diagnosis). True, NDT suppresses it even more, but the fact remains: I have had a suppressed TSH for a decade. I never felt right when I first went on T4 drugs, and doctors tried to keep my TSH between 2 and 4. I was then told that my remaining symptoms had nothing to do with my thyroid...

It is of course possible that I have been getting so used to being (over)stimulated on Erfa that, when I compare it to Armour, I feel less affected, and so I conclude that Armour is not working...when, in fact, Erfa is overstimulating me. That did not occur to me until now...

Thanks to all for your valuable input!


Actually, assuming thyroid hormones have a normal distribution (I think they do, unlike TSH), then the average FT3 value for a healthy individual should be exactly in the middle of the range by definition.

The reference ranges are usually created by taking blood from a sample of (hopefully healthy) people and working out the range that 95% of people fall into (ie 2 standard deviations from the mean). Most people will fall in the middle of the bell curve of a normal distribution with fewer at either extreme.

If there were some people with thyroid disease in the sample population then I'd expect the true healthy average to be a little bit above the midpoint as hypo is more common than hyper.


What most people, and especially doctors, fail to understand is that the thyroid function tests are incapable of telling a individual what is optimum for them. The tests only know there is a ballpark, they have no idea where home plate is for any given individual. What is most important for fine tuning is how you feel. PR


Here is an interesting link which shows that everyone's set point is different and doesn't really change. Problem is we don't know ours so its a guessing game I'm afraid. :-(.


G x


The other thing is that supplemental hormones, even NDT are not the same as the ones you produce yourself, and aren't delivered in that nice steady stream you get naturally. So although NDT is the best available, its necessarily a compromise.

How are you taking your huge dose? Are you splitting it up through the day? Are you taking it an hour before and 3-4 hours after food? Are you taking any supplements, and if so when? Such an unusually high dose would suggest that you aren't absorbing them properly.


I take the whole dose in the morning (as directed by my physician), then wait 30-60 minutes before having breakfast. I have tried splitting the dose but, apart from that being impractical for me, I felt no different compared to taking the whole dose in the worming.

I take Biovea Women's Multivitamins (at night as it contains iron, so at least eight hours away from NDT).


Your TSH is hugely suppressed...on that basis your are likely feeling quite hyper. Sometimes hyper feelings can be similar to hypo feelings...but you're still hyper!


...also, 5 grains it's a very high dose for most a anyone.


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