Switching from NDT back to T3 only: Is something... - Thyroid UK

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Switching from NDT back to T3 only

Nipitiri profile image
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Is something like NDT (T4) withdrawal symptoms possible?

To be exact, if you are on T3 only but due to some circumstances have to take NDT for a couple of weeks as a replacement and then again can switch back to T3 only, then because of the longer half-life of T4 (up to 9 days I've read), can it become a little messy and you might feel kind of sick, until T4 has been metabolized completely? And in the context that usually T4 only or T4 from NDT is not metabolized/converted well in the individual.

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Nipitiri
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DippyDame profile image
DippyDame

It will definitely become"messy"!

You don't say how much T3-only you were taking or how much NDT you took in the 2 week interval before returning to your original T3 protocol but the sudden change in hormone level/ availability would upset the system.

If you do not convert well...which I assume is why you introduced T3...then the T4 in the NDT is unlikely to help much, and more significantly the T3 content may be much lower that that of your T3-only dose.....so for 2 weeks your T3 has been reduced.

You don't give us the dose levels taken, so we cannot work out the possble impact they might have.

Anyway...the body had the change to NDT to deal with first then suddenly, in the middle of all this, it all changed again back to T3 only!

You are just going to have to put up with "the messy" until T4 clears from your system and T3 level is optimised again.

You will be feel off colour/ undermedicated...and give your system time to settle down. It won't happen overnight so you will need to be patient until the returned t3 dose settles back into the system.

So to answer your question, "Is something like NDT (T4) withdrawal symptoms possible?"

Of course...

but I wouldn't refer to this as" withdrawal symptoms ". Here, the change is causing undermedication, which in turn results in related symptoms.

Hope you get back on track soon.

Good luck

RockyPath profile image
RockyPath

As a science experiment, and to mess with the mind of my nutty endocrinologist, I suspended NDT for a mere two days and my FT4 plunged over a cliff and I felt rubbishy and cold.

That nine-day half-life is merely a wild guess of clinical averages that are based on people with normal thyroid function. (Ooooops.) The healthy people are skewing the results and causing insanity in the clinical staff.

Yes, some people do not convert synthetic T4 properly. Usually, they can convert animal-sourced T4 much better. Sometimes neither serves a good end.

You're definitely in the experimental zone. Keep good records. Note how you feel. Watch your pulse. Do you melt into a puddle and fall asleep at odd times of the day, and not wake for two hours?

Good luck.

Nipitiri profile image
Nipitiri

Don't really want to bring you all my bothering symptoms and details but your answers have assisted me in putting it together. I assumed a mess is quite obvious to come but I rather needed a confirmation since I've done the same switching through before but this time the messy afterparty feels bigger. In my case I can also blame the imbalance in my sex hormone levels (second half of the cycle with pms and all) that can affect the whole picture.

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