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Thyroid UK
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T3 Only

Hi, new to this group.

An alternative oncologist in NYC has recommended I transition from NDT to T3 only. I am thyroidectomy with thyroid cancer. This is based on evidence that T4 promotes growth of existing solid tumors.

I was on Naturethroid 1 grain three times daily. So far I have transitioned to Cytomel (generic) 25 mcg morning and Naturethroid 1 gr. afternoon.

Any advice on how to advance my T3 dose?

9 Replies

T3 usually best taken twice a day about 6-8 hrs apart. So maybe try replacing afternoon dose. Sorry I don’t know equivalent amounts to NDT


Welcome to the forum, Eoram25,

If you are happy on NatureThroid I would ask your oncologist to provide you links to that evidence rather than take it on face value. If oncologist is able to provide evidence I would appreciate you writing a new post to include it.

1 grain NatureThroid is equivalent to 25mcg T3.


Thanks! I have found a mountain of evidence to back up this suspicion about T4. I am in medicine and I did not know anything about it. Here is a summary article:




I can't access that link as I'm not a member of the Library.



You've had a thyroidectomy you no longer have thyroid tumours so why must you avoid T4?


Clutter is right when she suggests your Endo supply evidence of "This is based on evidence that T4 promotes growth of existing solid tumors."

When introducing T3 you can reduce NDT by 1/4 tablet and add 1/4 tablet of T3 (25mcg is approx equal, in its effect, to 100mcg of levo or 1gr of NDT). Every two weeks you can follow the same procedure and I hope you will feel much better with relief of all symptoms.

The following is a link by one of our Advisers (deceased) which you may find helpful. He would never prescribe levo - only NDT or T3.

The date of January 30, 2002 in particular and December 17, 1997



That is extremely helpful, many thanks. Here are a few articles on the T4/cancer connection:



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Hi - I have had a thyroidectomy for thyroid cancer which was already metastatic and has further metastasized. And its RAI-resistant. So I have to do anything and everything I can to keep it in check.

I'm sorry, that article seems to be behind a paywall. Here is the abstract:



Here is an abstract of the other article. This study shows that administering T3 instead of T4 results in solid tumor shrinkage and extended survival in cancer patients:



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