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Need advice regarding dosage and labs on NDT

Hello to everyone, this is my first post here.

I was diagnosed with micro papillary with follicular variant in April of 2007 and underwent a TT followed by 209 mCi RAI. I've been on various doses of synthroid for the past 10.5 years.

Most recently, I switched to NDT ERFA on August 11, 2017 from 175mcg Synthroid alternating with 162.5 every other day.

Back in late September my endo had lowered my dosage of ERFA from 90mg daily to 90 alternating with 60mg. I stayed on that dosage for a while but had a lot of issues being that low so I upped it myself to 90 alternating with 75mg. My to labs prior to lowering (on 90mg daily) were as follows:

FT3 5.8 Reference Range: 3.5-6.5

FT4 10.1 Reference Range: 9.0-23

TSH 0.03 Reference Range: 0.20-4.00

My endo insisted I lower my dosage even tho I told her I felt great. My latest labs are as follows:

FT3 4.4 Reference Range: 3.5-6.5

FT4 8.2 Reference Range: 9.0-23) I've been flagged as low

TSH 0.79 Reference Range: 0.20-4.00)

Thyroglobulin 0.2 (was 0.1 in January of 2017 when I was on Synthroid prior to switching to NDT ERFA)

Antithyroglobulin antibody less than 0.20 (ref less than 40)

My TSH has gone up a lot in a little over a months time and my FT4 is too low. My family doctor had the office phone after my labs came in and wants me to go back up to 90mg daily based on the latest labs. I met with my endo and she agreed with him and now I'm back on 90mg daily.

I've been feeling pretty awful; really depressed affect, no energy/stamina, sluggish digestion, etc.

I've tried dividing my dose into 45mg twice daily as well as 30 three times daily. Ive also tried taking 60mg in the am and 30 in the afternoon and visa versa. I've even tried to take 30mg in the middle of the night and the other two doses of 30mg at 8am and 2pm.

Nothing is helping me to feel appreciably better; to the contrary, I keep feeling worse as time goes by.

Another issue that is really bothering me is that of weight gain. I seem to be putting on weight since going on the NDT (was on Synthroid for over ten years) even though I'm eating/exercising the same as always. I don't want to give back and go back on Synthroid and could really use some advice.

Thank you.

12 Replies

Your doctors are just dosing by the TSH, aren't they. Always a mistake. They really don't know much about thyroid. You should not do alternate dosing with Erfa, because it contains T3, and the body needs a constant, regular dose of T3 if it is to heal. That just goes to show how little they know about it!

Also, when you are taking T3 or NDT, the FT4 is bound to be low. That doesn't matter. The most important number is the FT3. Yours could be higher. 90 mg is just one grain. You cannot expect someone without a thyroid to be well on just one grain. You need an increase in dose.

What is more, having had cancer, you need your TSH suppressed to minimise the possibility of any remaining thyroid cells regenerating, and with them, the cancer. I think you also need new doctors!


Hi Greygoose and thanks for your reply. I'm told that 30mg of ERFA is i/2 grain so I'm actually taking 1.5 grains daily (90mg). The end I see who is in charge of my care made a huge deal of my low TSH as did her two nurses who told me that I was setting myself up for a heart attack. That's why she insisted on lowering my dose 6 weeks after I began ERFA. Now that y numbers went up from alternating 90 and 75mg every other day she has me back up to 90 and wants to see me in one years time without doing any more labs whatsoever. She is expecting her first baby and told me my file would be handed over to another doctor while she's off on Mat leave. It is my understanding that there should always be follow up labs drawn after any dosage change; it seems very irresponsible for her to say they're not necessary. I feel that my care has been and continues to be suboptimal and am concerned that my concerns aren't even being heard. You mentioned that the Ft3 number could be higher; can you give me an idea of the optimal value? You also mentioned an increase in dose; wouldn't bother me to try that since I am and have been feeling hypo but what about the TSH that they're so alarmed about? Mine had been less than 0.03 on 90mg (1.5 grains) daily. Can I safely go lower than that? I am 64.5 years of age and I've heard it say that as we age we need less thyroid hormone. I'm in a tailspin and don't know what to do.


You're right. You should be retested six weeks after any dose change. And she is irresponsible. And she doesn't know very much about thyroid - nor do her nurses - because the TSH has absolutely nothing to do with the heart. Logically, how could the lack of a hormone that goes nowhere near the heart, cause you to have a heart attack? As long as your FT3 is in-range, you're ok.

The TSH has two jobs : a) it stimulates the thyroid to make more hormone, and when your thyroid can't respond, the TSH goes high, when you take thyroid hormone replacement, it goes down again; b) it stimulates conversion of T4 to T3, but as you're taking T3, you don't need it for that, either.

But, doctors do not understand the difference between a suppressed TSH caused by the high levels of FT3 in Grave's disease, and a suppressed TSH caused by taking the right amount of T3 exogenously. It's the long-term, very high FT3 in Grave's that increases the risk of heart problems, not the low TSH. The heart needs T3, but too much is dangerous and can over-stimulate the heart. Which is why I say, a suppressed TSH, when taking T3, is not a problem as long as the FT3 is in-range.

People with no thyroid problems need less thyroid hormone as they age. But, people on thyroid hormone replacement cannot be compared to people who aren't. Nothing functions in the same way, anymore. This is one of the reasons that thyroid care is so abysmal, they are always trying to compare us with healthy people, and don't understand that we are different.

You need what you need. Not what some thyroid-illiterate diabetes specialist thinks you ought to need. I can't give you a figure of what your FT3 should be, I can only say that it should be in the place where it makes you well. And, if that's at the top of the range, so be it. Optimal is how you feel, not a number on a lab result. I just meant that there was plenty of room for an increase if you felt you need it, without your FT3 going over-range. :)

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Grey goose, beautifully stated and very informative. The issue is how do we get adequate care when the doctors we're assigned to don't know the first thing about how to treat thyroid cancer survivors. It's been an uphill battle every step of the way for me; I tell them one thing and they insist I do another, then when the lab results come in they tell me to go back to where I was. I'm exhausted and weary of trying to treat this situation while butting heads with idiots who think they know my body better than I do. If I were to increase my dose by 15mg would I need to do it daily and not fluctuat every other day? As well, the ERFA pills aren't scored so it's quite difficult to know what you're actually getting once you cut them in half or quarters and there's always some wastage in the form of crumbling/particles.



You looked to be optimally dosed on 90mg Erfa previously. Rather surprising because 90mg is a very small dose for someone without a thyroid. 175mcg Synthyroid is equivalent to around 180mg Erfa.

Your endo was probably faffing about TSH being suppressed at 0.03. I don't think you were overmedicated because FT3 was within range. I was advised to keep TSH suppressed <0.1 post thyCa to reduce chances of recurrence.

Thyroglobulin 0.2 and thyroglobulin antibodies <20 is good and indicates no recurrence. I was advised that recurrence is rare when thyroglobulin remains <6.0.

It's likely to take up to six weeks to feel the full impact of the increased dose. If your symptoms don't improve I would increase dose to 120mg and retest six weeks later to ensure FT3 remains within range.

Hypothyroid patients are often low/deficient in ferritin, vitamin D, B12 and folate so ask your GP to test. Write the results and ranges in a new post and members will advise.


Hi Clutter and thanks for your reply. Yes, you are spot on; the endo was losing it over the low TSH even tho I used to be even lower on Synthroid. How low can we go on TSH? Before my dosage change I was at less than 0.03 and went up to 0.79 when they reduced my dose.

In May of 2017, approximately 2.5 months before switching to ERFA I underwent Thyrogen protocol (two injections) and my Thyroglobulin which had been 0.1 went up to 0.8 and then went back down over a few months to 0.2. Should i be concerned?

Thank you for your advice.



My TSH has been <0.01 since 2012 except when I've been off thyroid meds. It can go lower but its not desirable to have very suppressed TSH.

I don't think you need to be concerned about Thyrogen raising thyroglobulin as it went back down afterwards.



This is what I'm sketchy on; when labs for TSH come back 'less than 0.03' are they actually able to measure lower values? I distinctly recall being less than 0.01 during the years I was on Synthroid. I'm thinking perhaps it just depends on the lab? In any event, I never knew it wasn't desirable to fluctuate doses of ERFA every other day. I was initially told to take 60mg one day and 90 the next. I tried that and wasn't feeling well. The endo also advised to take the entire 90mg dose once daily but I never tried that. I'm currently taking 90mg dosed as 30 mg three times daily. One of my doses is in the middle of the night and the other two are at 8am and 3pm. The endo has scheduled an appointment for in in one years time with no testing until then. If I do get labs done at the request of my family physician he will no doubt instruct me to once again lower my dose when he sees my low TSH. I feel I'm between a rock and a hard place. According to everything I've read I could probably use a bit of a higher dose; not much, just enough to actually feel as if I'm among the living.



I certainly had a TSH result <0.001 once. I think it depends which analysis machinery is used how low it can be measured. As <0.01 is seen as too low usually it doesn't really matter whether it gets measured as accurately as 0.00000000000001.

NDT or T3 should be taken in regular daily doses ie 75mg daily not 60mg/90mg alternate days because the T3 is out of the blood after 6-8 hours.

Most people will take low doses of NDT or T3 in one or two daily doses but if your 3 x daily suits there's no need to change it.

Is there any way you can order your own labs? In the UK if the patient is under the care of an endocrinologist it is not good form for the GP to interfere with the endo's treatment plan.


Clutter, I could have sworn that I was also less than 0.001 at some point during the ten years on Synthroid. That's why I don't understand why they're making such a big deal of it now that I'm on ERFA. I refuse to go back on Synthroid; I feel I gave it a good run at over ten years. Lots of nasty side effects; glad to be done with them. Unfortunately I'm unable to order my own labs; that would be ideal. As an American now living in Canada I've seen the worst of both sides of the health care issue on either side of the border. The health care here can be rather dismissive and the emphasis appears to be to curtail lab work and such whenever possible. The endo usually doesn't even want to order Thyroglobulin; neither does the family physician; my peace of mind means nothing and they see no need for it. In the US they're more than happy to order tests but those of us without good/comprehensive healthcare must then pay out of pocket for them at exorbitant prices that most cannot afford. My concern is splitting that ERFA pill; since it's not scored how do I know how much I'm actually getting?



You won't get exact halves/quarters but they will be close enough if you cut the tablets with a pill cutter.

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